awi/sma standard for wood stair, handrail, and guard systems · a) provides standards for the...

Wood Stair, Handrail, and Guard Systems

Architectural Woodwork Institute46179 Westlake Drive, Suite 120, Potomac Falls, VA 20165

Phone: 571-323-3636, Fax: 571-323-3630http://www.awinet.org

AWI/SMA Standard

DRAFT AWI SMA 0643-20XXRevised January 14, 2020 3:44 PM

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AW

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43-2

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for

DRAFT AWI SMA 0643-20XX - Wood Stair, Handrail, and Guard Systems

ii Revised January 14, 2020 3:44 PM

Table of Contents1.0 Purpose ......................................................................................................12.0 Scope .........................................................................................................1

2.1 Included ....................................................................................................................12.2 Not Included .............................................................................................................1

3.0 Requirements ............................................................................................................... 23.1 General .....................................................................................................................2

3.1.1 Measurements ...................................................................................................23.1.2 Special Requirements ........................................................................................23.1.3 Environmental Conditions .................................................................................33.1.4 Manufacturer/Supplier Requirements for Installation .........................................33.1.5 Default Grade Requirements .............................................................................3

3.2 Material .....................................................................................................................43.2.1 Stairs, Components ............................................................................................................... 43.2.2 Risers .................................................................................................................73.2.3 Platforms and Intermediate Landings ................................................................83.2.4 Winders .............................................................................................................83.2.5 Guard and Handrail Components .....................................................................83.2.6 Handrails .........................................................................................................103.2.7 Rail and Fitting Connections ............................................................................ 113.2.8 Tolerances ........................................................................................................ 113.2.9 Fittings .............................................................................................................. 113.2.10 Guard In-Fill .....................................................................................................123.2.11 Well-Hole Trim .................................................................................................13

3.3 Structural ..............................................................................................................143.3.1 Stairways, Handrails, and Guard Systems.......................................................14

3.4 Aesthetic ................................................................................................................143.4.1 Transparent Finish ...........................................................................................153.4.2 Opaque Finish ..................................................................................................153.4.3 Treads (Including Winders) ..............................................................................153.4.4 Risers ...............................................................................................................173.4.5 Guard and Handrail Components ....................................................................173.4.6 Fittings ..............................................................................................................173.4.7 Guard, In-Fill ...................................................................................................183.4.8 Metal In-Fill/Guards .........................................................................................193.4.9 Well-Hole Trim ..................................................................................................203.4.10 Nosing, Well-Hole ............................................................................................203.4.11 Staircase (Assembled Unit)..............................................................................21

3.5 Fabrication .............................................................................................................213.5.1 Fabrication, Shop Assembled Stairs ................................................................213.5.2 Fabrication, Field Assembled Stairs .................................................................23

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Revised January 14, 2020 3:44 PM

3.6 Installation ............................................................................................................233.6.1 Field Assembled Stair Components .................................................................243.6.2 Stairs, Shop Assembled ...................................................................................253.6.3 Guard and Handrail Installation........................................................................263.6.4 Fittings .............................................................................................................263.6.5 Guard, In-Fill ....................................................................................................27

4.0 Figures / Illustrations ..............................................................................30Figure 88 - Gap, Tread and String ................................................................................30Figure 89 - Hybrid Tread ...............................................................................................30Figure 90 - Maximum Angle, Cross Grain Prevention ..................................................31Figure 91 - Plan View, Curved Handrail, Solid Block ....................................................31Figure 92 - Grain Orientation, Handrail Easing.............................................................32Figure 93 - Grain Orientation, Fitting Miter ...................................................................32Figure 94 - Grain Orientation, Fitting/Rail Joint ............................................................33Figure 95 - Grain Orientation, Volute/Turnout ...............................................................33Figure 96 - Grain Orientation, Easing Glue Lines .........................................................34Figure 97.......................................................................................................................34Figure 98 - Grain Orientation, Spiral Treads .................................................................35Figure 99.......................................................................................................................35Figure 100 - Concept ....................................................................................................36

5.0 Supplemental Information ......................................................................375.1 Exceptions to Material Requirements .................................................................37

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PurposeRevised January 14, 2020 3:44 PM

1.0 Purposea) Provide standards and tolerances for the quality fabrication and field installation of wood stair,

handrail, and guard systems (henceforth referred to as “Product”).

b) Establish minimum aesthetic and performance requirements intended to provide a well-defined degree of control over a project’s quality of materials, workmanship, and/or fabrication.

2.0 Scopea) Provides standards for the manufacture and installation of wood stair, handrail, and guard

systems for residential and commercial applications, as well as guard in-fill system components of metal, glass, and cable.

2.1 Includeda) 06 43 00 Wood Stairs and Railings

2.2 Not Includeda) Substructures of materials other than wood

b) Product as specified under CSI MasterFormat Division:

• 05 00 00 Metals

• 06 50 00 Structural Plastics

• 09 65 00 Resilient Flooring

c) Welding, polishing, grinding, machining, and finishing of metal components

d) Structural components, grounds, in-wall blocking, backing, furring, support brackets, strapping, mechanical systems in the stairwell or immediate vicinity, or other anchorage that becomes an integral part of the building’s walls, floor systems, or ceilings are not furnished or installed under the scope of this standard’s requirements.

e) Installation of Product items not specifically identified in itemized scope of work within the contract documents.

f) Providing and installing electrical related items, light fixtures, network cables, grommets and wire management systems, computer equipment, or mechanical equipment.

g) Correction of existing jobsite conditions that are required for the installation of the Product.

h) All site-applied primers, stains, or other finish coatings for non-factory finished Product.

i) Filling nail or screw holes in unfinished or primed Product.

j) Caulking to fill voids between Product and pre-existing surfaces.


2 RequirementsRevised January 14, 2020 3:44 PM

3.0 Requirements3.1 General

a) Submittals shall be in accordance with AWI 100 – Submittals.

b) The following requirements shall govern unless a project’s contract documents require otherwise.

c) Should a conflict be discovered within this standard, the least restrictive requirement shall prevail.

d) Where required by contract documents, manufacturer/supplier shall verify field measurements and fabricate Product accordingly.

e) Structural components, including (but not limited to) blocking, grounds, backing, furring, brackets, or other anchorage shall be an integral part of the building’s structure and designed to support the required live loads. Such components that are required for the installation of Product are not furnished or installed by the Product manufacturer/supplier or installer. However, manufacturer/supplier shall provide drawings indicating location of anchorage/blocking as outlined in the AWI 100 - Submittals Standard.

f) For the purposes of this standard, inconspicuous shall be defined as not readily visible without careful inspection at a distance of:

Premium Custom Economy610mm [24”] 1219mm [48”] 1829mm [72”]

3.1.1 Measurementsa) This standard is written with the metric system of measurement followed by the U.S.

Customary System of measurement in brackets.

b) The system of measurement used in the project’s original contract documents and architectural drawings will dictate which system of measurement within these standards is used for verification of compliance.

c) The U.S. Customary measurement is typically a “soft” conversion of the metric measurement. In order to make the metric number more conceptually coherent and consistent, most conversions for less than 152.4mm [6”] in dimension are “soft” converted to the nearest 0.1 mm. For measurements above 152.4mm [6”], the “soft” value is converted to the nearest 1 mm.

d) Should a conflict be discovered within this standard, the least restrictive requirement shall prevail.

e) Gaps and flushness between adjacent, exposed components shall be tested with a feeler gauge at points where components are required to contact as indicated within this standard.

3.1.2 Special Requirementsa) The authority having jurisdiction for enforcement of the applicable building code shall

be stated in contract documents by the design professional. (See applicable SMA Visual Interpretations)

b) Where special physical and/or environmental construction requirements (e.g. seismic, flood, and/or high velocity wind) are required, such requirements and details shall

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Requirements, GeneralRevised January 14, 2020 3:44 PM

be clearly stated in the contract documents. Requirements for Product, such as preservative treated, moisture resistant, or fire retardant materials, shall be specified by the design professional.

c) If preservative treatment, chemical resistance, fire retardancy, or moisture resistance is required, fasteners shall be stainless steel.

3.1.3 Environmental Conditionsa) Requirements of this standard are contingent upon maintaining proper interior

environmental controls prior to, during, and after installation. See the AWI 200 – Care & Storage Standard.

b) This standard does not establish grade requirements for joint flushness and gap tolerances for Product installed in a non-climate-controlled environment.

c) Prior to installation, the flushness and gap tolerances of Products intended for non-climate-controlled environments shall meet the test requirements herein.

3.1.4 Manufacturer/Supplier Requirements for Installationa) Manufacturer/supplier shall fabricate/construct wood stair, handrail, and guard

systems to meet the project specifications and the architectural drawings. Where field measurements are required, manufacturer/supplier shall fabricate/construct wood stair, handrail, and guard systems to fit within the opening provided. However, where floor, wall, ceiling, and/or opening variations occur in excess of 6.4mm [.250”] in 2438 mm [96”] of being plumb, level, flat, straight, square, or of the correct size, such are not acceptable for the installation of Product. It is not the responsibility of the installer to scribe or fit to walls, ceilings, floors, or openings whose plumb, level, flat, straight, or square values exceed tolerances specified in contract documents.

b) The wood stair, handrail, and guard system manufacturer/supplier is responsible for coordinating with the flooring manufacturer/supplier. Unless otherwise specified, flooring manufacturer/supplier is responsible for furnishing and installing floor materials at landings and floors necessary for proper setting of landing treads and nosing.

c) Manufacturer/supplier shall provide the installer with written guidelines and/or shop drawings for the proper installation of their product, including anchorage method and fastening. Guidelines and/or shop drawings shall include fastener details.

d) Responsibility for materials and installation of platforms and intermediate landings shall be specified in contract documents. In the absence of specification, verification of responsibility for materials and installation of platforms and intermediate landings shall be obtained in writing prior to the commencement of work.

e) Location and size of platforms and intermediate landings shall be determined to conform with adjoining flights, as specified in manufacturer/supplier’s approved shop drawings.

3.1.5 Default Grade Requirementsa) If not otherwise specified or indicated, all wood stair, handrail, and guard systems shall

be custom grade.


4 Requirements, MaterialRevised January 14, 2020 3:44 PM

3.2 Materiala) Materials used for construction of Product covered within the scope of this standard shall

adhere to the requirements set forth in the AWI 300 - Materials Standard.

b) Sapwood and other characteristics are permitted where specified.

c) For all materials selected for the manufacture of wood stair, handrail, and guard systems:Premium Custom Economy

Sapwood, spot-worm holes, and knots are not permitted

Spot-worm holes not exceeding 1.6 mm [.063”] in diameter are permitted at a maximum of one per linear 305 mm [12”]

Spot-worm holes not exceeding 1.6 mm [.063”] in diameter are permitted at a maximum of two per linear 305 mm [12”]

Worm holes, knots, and similar imperfections shall be filled and sanded

Flaws and defects shall be kept to a minimum and shall be filled and sanded prior to finishing

A maximum of two streaks are permitted in any tread provided they do not exceed 152.4 mm [6”] in the aggregate

Streaks and bright sapwood are permitted

Slightly chipped grain, streaks, and bright sapwood are permitted

A maximum of one sound-tight knot not exceeding 6.4 mm [.250”] in diameter is permitted per linear 914 mm [36”]

A maximum of one sound-tight knot not exceeding 6.4 mm [.250”] in diameter is permitted per linear 305 mm [12”]

Material shall be well-matched for color and grain

Material shall be compatible for color and grain

Material shall be at the option of the manufacturer/supplier

d) Materials used for the same purpose, within the scope of this standard, shall be consistent throughout a project.

e) Concealed surfaces shall permit aesthetic defects.

f) Blocking, fillers, and shim stock shall be of sound material.

g) Sealants and/or adhesives shall be compatible in color to adjacent surfaces. Sealants and/or adhesives shall be used in accordance with manufacturer/supplier’s documented instructions.

h) All glue seams shall be tight and surface residue shall be completely removed.

i) The number of knots and imperfections may vary when trying to match “rustic” styles or finishes and/or reclaimed materials. Where matching of “rustic” styles or finishes and/or reclaimed materials is specified, number of permitted imperfections shall be as agreed upon between buyer and seller.

3.2.1 Stairs, Components

3.2.1.1 Exposed Stringers and Skirtboardsa) Stringers shall be a minimum of 19.1 mm [.750”] thick.

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Requirements, MaterialRevised January 14, 2020 3:44 PM

b) At stringers exceeding 4.27 meters [14’] long, joining for length is permitted. For exceptions, see 5.1 Exceptions to Material Requirements.

c) Wood selected to make up stringers shall be joined and glued in a manner that eliminates visible glue lines.

d) Individual staves shall have a maximum of one end joint per 7.315 meters [24’] and, at edge-glued stock (For exceptions, see 5.1 Exceptions to Material Requirements):

Premium Custom EconomyThere shall be no more than three staves per 305 mm [12”] in width

There shall be no more than five staves per 305 mm [12”] in width

Stringers shall be made up of staves no less than 50.8 mm [2”] in width

Individual staves shall be well-matched for color and grain

Individual staves shall be compatible for color and grain

Individual staves shall be at the option of the manufacturer/supplier

e) At edge-glued stock, staves shall be lap jointed, finger jointed, doweled, or splined to achieve desired length. End joints in staves shall be staggered. At laminated stringers, face butt joints in exposed laminations are permitted.

f) Stringers shall be structurally sound, without splits or checks, and without knots within 50.8 mm [2”] of the edges. This requirement does not apply to non-structural skirtboards.

3.2.1.2 Stringers, Concealeda) The following materials are permitted:

Premium Custom EconomyEngineered Material – glued laminated timber (Glulam), laminated veneer lumber (LVL), parallel strand lumber (PSL)

Engineered Material – glued laminated timber (Glulam), laminated veneer lumber (LVL), parallel strand lumber (PSL)

#1 common structural, fir, hem-fir, southern yellow pine (SYP) with no knots within 152.4 mm [6”] of bottom edge

3.2.1.3 Treads, Wooda) Shall be a minimum of 19.1 mm [.750”] thick.

b) At glued-up stock:Premium Custom Economy

Each tread shall consist of no more than three staves per 305 mm [12”] in width

Each tread shall consist of no more than five staves per 305 mm [12”] in width

Number of staves shall be at the option of the manufacturer/supplier

Individual staves shall be well-matched for color and grain

Individual staves shall be compatible for color and grain

Individual staves shall be compatible for color

c) When joined and glued, shall have no visible glue lines.

3.2.1.4 Treads, Hybrida) Are typically made of a solid wood of an economical species, joined by finger

joints to a more expensive wood end and return. Use of hybrid treads at stairs with a runner or similar detail is permitted.



b) Finger joints in hybrid treads are permitted, provided enough “finish” material remains on exposed end to thoroughly conceal joint.

c) Exposed tread material shall adhere to “Custom Grade” material guidelines.

3.2.1.5 Treads, Engineered (Veneered)a) Shall have balanced veneer faces with an engineered substrate and a minimum

thickness of 25.4 mm [1”].

b) Nosing edge shall be solid material a minimum of 31.75 mm [1.250”] wide and of the same species as veneer.

c) Exposed ends shall be returned with the same species as veneer in order to completely conceal the substrate.

3.2.1.6 Treads, Plank (Slab)a) Are defined as any tread 38.1mm [1.500”] or thicker

b) Sapwood and knots are not permitted at exposed faces of treads.

c) Exposed laminations used to make plank treads shall be a minimum of 19.1 mm [.750”] thick and consist of staves joined and edge-glued with no visible glue lines.

d) Laminations shall be of similar thickness throughout stair.

e) Order/thickness of laminations shall be consistent throughout stair.

f) Exposed end grain is permitted.

g) Vertical laminations or horizontal laminations are permitted as specified.

3.2.1.7 Treads, Carpet Gradea) All treads that do not fall under the scope of 3.2.1.3 through 3.2.1.6 are considered

carpet grade.

b) Shall have a minimum thickness of 19.1 mm [.750”].

c) Shall be of a sub-floor grade material or solid wood that is structurally sound or designed specifically for carpeted applications.

d) OSB treads are permitted, however, their use shall adhere to their intended manufacturing specification (e.g. indoor or outdoor applications).

e) Up to four sound knots, not exceeding 38.1 mm [1.500”] in diameter are permitted at solid wood treads, provided they are not within 50.8 mm [2”] of the nosing edge.

f) Finger joints are permitted.

3.2.1.8 Treads, Landinga) Unless otherwise specified, landing treads shall be made of the same species as

the adjacent treads.

b) Nosing of landing tread, at the exit of a flight, shall be made to match the thickness, profile, and projection of the treads throughout stair.

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c) At the exit of a flight, shall be set so that the top surface is flush with flooring and is securely fastened.

d) Curved landing tread shall curve no greater than 45 degrees in a single section.

e) Curved landing tread shall be furnished in such sections as to avoid pronounced cross grain and reduce joints to a minimum.

f) Material for landing tread shall be:Premium Custom Economy

Well-matched for color and grain to adjacent treads and landing flooring

Compatible for color and grain to adjacent treads and landing flooring

At the option of manufacturer/supplier

3.2.1.9 Treads, Returned Endsa) At treads, ends shall:

Premium Custom EconomyBe returned to match the leading edge of the tread and conceal all exposed end grain, including end grain of the return

Be returned to match the leading edge of the tread and conceal end grain of the tread

Have profiled ends match the leading edge of the tread

b) At winders in curved stairways shall have:Premium Custom Economy

Both edges concentric with curve of stair

Both edges concentric with curve of stair

Returns at the option of the manufacturer/supplier

3.2.1.10 Treads, Curved (Bowed) and Starting Stepsa) Exposed end grain is permitted. Nosing profile shall be consistent.

b) Grain shall be oriented to minimize end grain exposure at the path of travel.

3.2.2 Risersa) Shall be a minimum of:

Premium Custom Economy19.1 mm [.750”] thick 19.1 mm [.750”] thick 12.7 mm [.500”] thick

3.2.2.1 Risers, Transparent Finisha) At transparent finish risers:

Premium Custom EconomyThere shall be no more than two staves per riser. Individual staves shall be well-matched for color and grain and grain riser shall be well-matched for color and grain to adjacent tread.

There shall be no more than three staves per riser. Individual staves shall be compatible for color and grain to adjacent tread.

There shall be no more than four staves per riser. Staves shall be compatible for color.

b) When joined and glued, shall have no visible glue lines.



3.2.2.2 Risers, Opaque Finisha) Edge gluing and finger joints are permitted.

b) Filling and sanding of defects is permitted.

3.2.2.3 Risers, Curved (Bowed) or Starting Stepsa) Species shall match adjacent risers in the stair at transparent finish.

b) Risers at curved or starting steps shall be:Premium Custom Economy

Solid kerfed stock with backer or solid form to maintain radius

Solid kerfed stock or kerfed veneered plywood stock with backer or solid form to maintain radius

Kerfed or bending plywood backer or solid form to maintain radius

3.2.3 Platforms and Intermediate Landingsa) Unless otherwise specified, flooring manufacturer/supplier is responsible for furnishing

and installing floor materials at landings and floors necessary for proper setting of landing treads and nosing.

b) Plank (slab) platforms shall be constructed with allowances for expansion and contraction and:

• Are defined as 38.1mm [1.500”] or thicker

• Sapwood and knots are not permitted at exposed faces.

• Exposed laminations used to make slabs shall be a minimum of 19.1 mm [.750”] thick and consist of staves joined and edge-glued with no visible glue lines.

• Laminations shall be of similar thickness throughout stair.

• Order/thickness of laminations shall be consistent throughout stair.

• Exposed end grain is permitted.

• Vertical laminations or horizontal laminations are permitted as specified.

c) Flooring materials used on platforms and intermediate landings shall permit expansion and contraction.

3.2.4 Windersa) Grain shall run parallel to leading edge.

b) Shall be of the same material and nosing profile as adjacent treads.

3.2.5 Guard and Handrail Components3.2.5.1 Newels, Transparent Finish

a) Veneered faces are permitted.

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b) At solid newels:Premium Custom Economy

Laminations a minimum of 25.4 mm [1”] thick and of the same species are required

Laminations a minimum of 19.1 mm [.750”] thick and of the same species are required at newels 101.6 mm [4”] or less Laminations a minimum

of 19.1 mm [.750”] thick and of the same species are required

Laminations shall be a minimum of 31.8 mm [1.25”] at newels exceeding 95.3 mm [3.75”] in diameter and be of similar thickness

Laminations shall be a minimum of 25.4 mm [1”] at newels exceeding 101.6 mm [4”] in diameter

Edge gluing is not permitted

Edge gluing is permitted at center laminations, provided color remains compatible after turning

Edge gluing is permitted at laminations, provided color remains compatible after turning

Components shall be well-matched for color and grain

Components shall be compatible for color and grain

Components shall be compatible for color

c) At box (hollow) newels:Premium Custom Economy

Edge gluing of faces is permitted at a maximum of two staves per 203.2 mm [8”] or wider.

Edge gluing of faces is permitted at a maximum of three staves per 152.4 mm [6”] or wider.

Edge gluing of faces is permitted

Staves and sides shall be well-matched for color and grain

Staves and sides shall be compatible for color and grain

Staves and sides shall be compatible for color

Corners shall be mitered Corners shall be miteredCorners shall be mitered or butted at the option of the manufacturer/supplier

d) Finger joints are not permitted.

e) Solid squares are permitted if the surface and core moisture content are equal.

f) Stile and rail construction of box newel sides with panels is permitted.

3.2.5.2 Newels, Opaque Finisha) At opaque finish newels:

Premium Custom EconomyEdge gluing and finger joints are not permitted

Edge gluing and finger joints are permitted.

Edge gluing and finger joints are permitted.

Filling and sanding of defects is not permitted

Filling and sanding of defects is not permitted

Filling and sanding of defects is permitted

b) Solid squares are permitted if the surface and core moisture content are equal.

c) Stile and rail construction of box newel sides with panels is permitted.



3.2.6 Handrails3.2.6.1 Handrails, Straight

a) Shall be laminated to ensure straightness.

b) Glue lines from horizontal laminations shall not be visible from the top view of the rail.

c) All visible laminations shall be of the same species and grade.

d) At straight handrails:Premium Custom Economy

Rails not exceeding 4.72 meters [15’6”] long shall be all solid laminations

The top rail lamination not exceeding 3.56 meters [11’8”] long shall be all solid

Finger joints are permitted in the top rail lamination at intervals equal to or exceeding 914.4 mm [36”] long

One staggered joint is permitted at the top rail lamination exceeding 4.72 meters [15’6”] long

One staggered joint is permitted at the top rail lamination exceeding 3.56 meters [11’8”] long

Staggered joints at top rail laminations at the option of the manufacturer/supplier

Finger joints and edge gluing are not permitted

Finger joints are permitted at lower laminations

Finger joints are permitted at lower laminations

Laminations shall be well-matched in color

Laminations shall be compatible in color

Color of laminations shall be at the option of the manufacturer/supplier

e) For individual material lengths by species, see 5.1 Exceptions to Material Requirements.

3.2.6.2 Curved Handrails, Bendinga) Bending rails composed of vertical or horizontal laminations are permitted.

Number of laminations is dependent on the radius, height, and width of the rail.

b) Material shall be:Premium Custom Economy

Well-matched for color and grain

Compatible for color and grain Compatible for color

c) Lamination prior to resawing and profiling is permitted.

d) Finger joints are permitted:Premium Custom Economy

At vertical laminations exceeding 4.72 meters [15’6”] long

At vertical laminations exceeding 3.56 meters [11’8”] long

At the option of the manufacturer/supplierAt a maximum of one

per each lamination exceeding 4.72 meters [15’6”] long

At a maximum of one per each lamination exceeding 3.56 meters [11’8”] long

e) For individual material lengths by species, see 5.1 Exceptions to Material Requirements.

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f) At outside vertical laminations exceeding 4.72 meters [15’6”] long, scarf joints are permitted.

3.2.6.3 Curved Handrails, Cut from Solid Blocksa) Curved level rail shall be laminated with a minimum of 19.1 mm [.750”] thick

laminations.

b) Individual segments that make up curved level rail segments shall be 45 degrees or less (See Figure 91).

c) Solid stock or block lamination components shall be furnished in such sections as to avoid pronounced cross grain and reduce joints to a minimum.

d) Curved rake rail shall have minimum of 34.9 mm [1.375”] thick laminations. No more than four laminations are permitted to be visible on a section of rail.

3.2.7 Rail and Fitting Connectionsa) Rail to rail and rail to fitting joints shall be joined with glue and concealed hardware.

3.2.8 Tolerancesa) Factory machining tolerances for profiles of mating components shall not exceed .8

mm [.031”].

3.2.9 Fittingsa) Finger joints are:

Premium Custom Economy

Not permitted Not permittedPermitted at lower laminations of vertical drops of goosenecks

b) Materials shall be furnished in such sections as to avoid pronounced cross grain and reduce joints to a minimum (See Figure 90).

c) Grain shall be no greater than 45 degrees perpendicular to adjoining rails (See Figure 94).

d) At fittings turning over 45 degrees, miter joints are permitted (See Figure 93).

e) At volutes and turnouts, grain orientation of center laminations shall be rotated relative to top and bottom laminations to minimize short grain instability (See Figure 95).

f) Easings shall have a lamination thickness which prevents exposure of glue lines at the top of the rail (See Figure 96).

g) Wreathed transitions shall have minimum of 34.9 mm [1.375”] thick laminations.



3.2.10 Guard In-Fill3.2.10.1 Wood Balusters, Transparent Finish

a) At transparent finish wood balusters:Premium Custom Economy

Components shall be composed of one solid piece where not exceeding 57.2 mm [2.250”] thick



Turned and flat sections shall be sanded prior to finishing


Sanding shall be at the option of the manufacturer/supplier

3.2.10.2 Wood Balusters, Opaque Finisha) Laminated squares are permitted and:


Finger joints are not permitted

Staggered finger joints are permitted at laminated squares

Staggered finger joints are permitted at laminated squares



Sanding shall be at the option of the manufacturer/supplier

3.2.10.3 Wood, Other Wood In-Filla) Wood in-fill shall be compatible with other components within guard and stair

system. Species specification shall be in accordance with AWI 300 – Materials Standard.

3.2.10.4 Balusters, Metala) Shall be:

Premium Custom EconomySolid bar construction or a hollow tube with wall thickness of a minimum of 1.2 mm [.047”]

Solid bar construction or a hollow tube with wall thickness of a minimum of 1.2 mm [.047”]

Hollow bar construction with wall thickness between 1.2 mm [.047”] and .8 mm [.031”]

3.2.10.5 Cable Rail Systemsa) Components shall be of material appropriate to their intended application (i.e. of

the correct material or alloy):

• At exterior applications, if stainless steel is used as a part of cable rail systems, a minimum of type 316 is required

• At interior applications, if stainless steel is used as a part of cable rail systems, a minimum of type 304 is required

• Cable shall be a minimum of type 316 stainless steel

b) Components in direct contact with one another shall be of the same material to prevent galvanic corrosion, especially around fittings.

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• If this is unachievable, the components in question shall be of compatible material to keep corrosion to a minimum.

c) The parts and materials in the cable rail system shall be consistent throughout the product to ensure proper adherence to mechanical and aesthetic tolerances.

d) Cable strand count and configuration shall allow for manufacturer recommended tensioning without undue stretching and sagging.

e) All pre-manufactured cable components and/or hardware shall be installed in accordance with manufacturer/supplier’s documented instructions for assembly and installation.

3.2.10.6 Glass In-Filla) Glass used for in-fill shall be in accordance with ANSI Z97.1 (Latest Edition) and

ASTM C1036 (Latest Edition) Standard Specification for Flat Glass.

b) All glass in a stair system shall be made using the same manufacturing process and from the same batch, whenever possible, to prevent differences in color and clarity.

c) All edge treatments and polishing of glass panels shall be consistent throughout the stair system.

d) Glass mounting systems using metal to metal connections (i.e. glass clamps with metal posts) shall be of the same material to prevent galvanic corrosion.

e) Material used for mounting glass panels shall be appropriate for the intended application (i.e. indoor vs outdoor or wood mount vs concrete)

f) All pre-manufactured glass components and/or hardware shall be installed in accordance with manufacturer/supplier’s documented instructions for assembly and installation.

3.2.10.7 Metal In-Filla) Shall be compatible with other components within the guard system.

b) Within the guard system, shall be fabricated in accordance with current NAAMM/NOMMA AMP 555.

3.2.11 Well-Hole Trima) Material, such as nosing, fascia, scotia, curbing, caps, and shoe rail shall be

compatible with other materials used in the stair and guard systems.

3.2.11.1 Nosing, Well-Holea) Unless otherwise specified, well-hole nosing shall be made of the same species

as the adjacent treads, and/or landing tread.

b) Unless otherwise specified, well-hole nosing shall be made to match the thickness, profile, and projection of the treads and/or landing tread throughout the stair.

c) Curved well-hole nosing shall curve no greater than 45 degrees in a single section.


14 Requirements, StructuralRevised January 14, 2020 3:44 PM

d) Curved well-hole nosing shall be furnished in such sections as to avoid pronounced cross grain and reduce joints to a minimum.

e) Material for well-hole nosing shall be:Premium Custom Economy

Well-matched for color and grain to adjacent treads and landing tread

Compatible for color and grain to adjacent treads and landing tread

At the option of manufacturer/supplier

3.3 Structural3.3.1 Stairways, Handrails, and Guard Systems

3.3.1.1 Residential – (One or Two Family Homes of No More than Three Stories with Separate Means of Egress)

a) Stairways, Handrails, and Guard Systems in this type of residence shall be built as designed by the engineer of record or in accordance with the design approved by the authority having jurisdiction to enforce the applicable code of the jurisdiction. Where no code exists and/or is enforced, the design shall comply with the live load requirements specified of the most current edition of International Residential Code as published by the International Code Council.

3.3.1.2 Other Residential Stairways and Stairways in All Other Occupanciesa) Stairways, Handrails, and Guard Systems in these occupancies shall be built as

designed by the engineer of record or in accordance with the design approved by the authority having jurisdiction to enforce the applicable code of the jurisdiction. Where no code exists and/or is enforced the design shall comply with the live load requirements of the most current edition of International Building Code as published by the International Code Council.

3.4 Aesthetica) Number of permitted knots and imperfections may vary when trying to match “rustic” styles

or finishes and reclaimed materials, if specified.

b) Tolerances for imperfections or defects shall be in accordance with AWI 300 - Materials Standard.

c) Exposed surfaces shall be free of tooling and chatter marks.

d) Residual marks, including adhesive and filler residue, on exposed and semi-exposed surfaces shall be removed.

e) Fasteners, except nails, shall be:Premium Custom Economy

Concealed Concealed Concealed at the option of the manufacturer/supplier

f) When nails are used, they shall be properly set. Nail holes shall be filled by the finisher. Filler material shall be compatible with Product finish.

15


Requirements, AestheticRevised January 14, 2020 3:44 PM

g) Exposed surfaces of all materials shall be sanded:Premium Custom Economy

To a minimum of 120-150-grit finish

To a minimum of 120-grit finish Where specified

h) Wood selected to make up components shall be joined and glued in a manner that eliminates voids and visible glue lines.

i) Reveals shall be consistent between like parts throughout the system.

j) Profiles used for the same purpose, within the scope of this standard, shall be consistent throughout a project.

k) Glue or filler shall be inconspicuous and match the adjacent surface.

l) Materials used for the same purpose, within the scope of this standard, shall be consistent throughout a project.

m) Telegraphing is not permitted.

3.4.1 Transparent Finisha) Unless otherwise specified, Product shall be finished with a finishing technology (See

AWI Finishing Standard, Current Edition) of the manufacturer/supplier’s choice.b) Exposed faces:

Premium Custom EconomyDefects and imperfections shall be inconspicuous after sanding

Defects and imperfections shall be inconspicuous after sanding

Permit defects at the option of the manufacturer/ supplier

Shall be well-matched for color and grain between like and adjacent components of the same material

Shall be compatible for color and grain between like and adjacent components of the same material

Shall be compatible for color between like and adjacent components of the same material

3.4.2 Opaque Finisha) Unless otherwise specified, Product shall be finished with a finishing technology (See

AWI Finishing Standard, Current Edition) of the manufacturer/supplier’s choice.

b) All imperfections in exposed faces shall be repaired, filled, and sanded before painting.

3.4.2.1 Stringers, Laminateda) Exposed laminations within stringers shall be of similar thickness.

b) Face laminations shall be consistent between like parts within the stair.

c) Butt joints of laminations in a stringer shall be staggered.

d) Laminations of stringers shall be glued and clamped to provide tight and flush joints.

3.4.3 Treads (Including Winders)a) Nosing projections and profiles shall be consistent throughout the stairway.

b) Grain shall run parallel to the leading edge of the tread.


16 Requirements, AestheticRevised January 14, 2020 3:44 PM

3.4.3.1 Treads, Returneda) Tread ends shall:

Premium Custom EconomyBe returned to match the leading edge of the tread and conceal all exposed end grain, including end grain of the return

Be returned to match the leading edge of the tread and conceal end grain of the tread

Have profiled ends match the leading edge of the tread

b) Shall be fastened to ensure a tight fit to the end of the tread.

c) Shared surfaces of tread and return shall be sanded flush.

d) Grain orientation of curved returns shall:Premium Custom Economy

Minimize exposed end grain on the edge

Minimize exposed end grain on the edge

Be at the option of the manufacturer or supplier

e) Returned ends of winders in curved stairways shall:Premium Custom Economy

Have both edges of the return concentric with curve of stair

Have both edges of the return concentric with curve of stair

Be at the option of the manufacturer or supplier

3.4.3.2 Treads, Spiral (Unsupported By Riser)a) Grain direction shall (See Figure 98):

Premium Custom EconomyRun parallel to the leading and trailing edge of the tread

Be at the option of the manufacturer/supplier

Be at the option of the manufacturer/supplier

3.4.3.3 Treads, Plank (Slab)a) Are defined as any tread 38.1mm [1.500”] or thicker

b) Sapwood and knots are not permitted at exposed faces of treads.

c) Sapwood and other characteristics are permitted where specified.

d) Exposed laminations used to make plank treads shall consist of staves joined and edge-glued in a manner that ensures no visible glue lines.

e) Laminations shall be in accordance with section 3.2.1.6 Treads, Plank (Slab).

f) Order/thickness of laminations shall be consistent throughout stair.

g) Exposed end grain is permitted.

17



3.4.4 Risersa) Shall be a minimum of:

Premium Custom Economy19.1 mm [.750”] thick 19.1 mm [.750”] thick 12.7 mm [.500”] thick

3.4.4.1 Risers, Curved (Bowed) or Starting Stepsa) Telegraphing caused by kerfing is not permitted.

b) Where available material lengths require construction to be of multiple components; joints in face material shall be kept to a minimum. Joints shall be placed in inconspicuous locations, where possible.

3.4.5 Guard and Handrail Components3.4.5.1 Newels

a) At connections to stair components other than rails, gaps shall not exceed:Premium Custom Economy

.8 mm [.031”] .8 mm [.031”] 1.6 mm [.063”]

3.4.5.2 Handrailsa) All rail to rail and rail to fitting joints shall be sanded and/or sculpted for seamless

profile alignment to the following flushness tolerances:Premium Custom Economy

.4 mm [.016”] .4 mm [.016”] .8 mm [.031”]

b) At rail to newel, rail to rail, and rail to fitting, gaps shall not exceed 20 percent of the joint perimeter and shall not exceed:

Premium Custom Economy.4 mm [.016”] .4 mm [.016”] .8 mm [.031”]

c) Plugs at joints are permitted provided they are sanded flush and of compatible color, grain, and grain direction.

3.4.6 Fittings3.4.6.1 Fittings, Transparent Finish

a) Grain and color shall match as specified and, if not specified:Premium Custom Economy

Grain and color shall be well-matched

Grain and color shall be compatible Color shall be compatible

b) Finger joints are:Premium Custom Economy


c) Flush plugs at joints are permitted where grain and color are matched to the adjacent surface and sanded flush.



d) Visible fasteners are not permitted unless specified.

e) Countersunk metal splines are permitted, provided the slots have been filled and sanded flush.

3.4.6.2 Fittings, Opaque Finisha) Shall be close-grained wood.

b) Flush plugs at joints are permitted where sanded flush.

c) Visible fasteners are not permitted unless specified.

d) Countersunk metal splines are permitted, provided the slots have been filled and sanded flush.

3.4.7 Guard, In-Fill3.4.7.1 Wood Balusters and Wood In-Fill Joinery, Transparent and Opaque

Finisha) At round end (no shoulder) in drilled holes, gaps shall not exceed:

Premium Custom Economy.4 mm [.016”] .8 mm [.031”] 1.6 mm [.063”]

b) At round or square end (with shoulder), where not in plow, gaps shall not exceed:Premium Custom Economy

.4 mm [.016”] .8 mm [.031”] .8 mm [.031”]

c) At square end in plow with fillet, gaps shall not exceed:Premium Custom Economy

.8 mm [.031”] .8 mm [.031”] 1.6 mm [.063”]

d) All joints in wood in-fill panels and panel systems shall be smooth and flush.

3.4.7.2 Balusters and Newels, Metala) Where applicable, finish shall be complete over the specified area. Slight surface

or edge contour irregularity is acceptable with no evidence of grinding or gouging, and:

Premium Custom EconomyNicks and blemishes are not permitted

Nicks and blemishes are not permitted

Minimal nicks or blemishes are permitted

b) (Compare to NAAMM/NOMMA AMP 500-2008 Metal Finishing Manual)

c) Metal balusters and newels with shoes shall have:Premium Custom Economy

Epoxy shoe centered on baluster or newel and fit to match pitch of stair


Shoes at the option of the manufacturer/supplier

Set screws not permitted Set screws not permitted Set screw at the option of the manufacturer/supplier

d) Metal balusters and newels without shoes shall be:

19



Premium Custom EconomyMortised to fit end of baluster or newel

Mortised to fit end of baluster or newel

At the option of the manufacturer/supplier

3.4.7.3 Cable In-Filla) All fitting and hardware components shall have compatible finish.

b) Exposed cable ends are not permitted.

c) All sections of cable in-fill shall be tensioned equally.

d) Where cables pass through wood posts at vertical or horizontal transitions, post protectors shall be used.

e) Spreader bars shall be spaced equally and securely fastened.

f) Bushings shall be used to isolate reactive materials and prevent electrolysis.

3.4.7.4 Glass In-Fill/Guardsa) All hardware components shall have compatible finish.

b) All glass shall be compatible in appearance.

c) All exposed edge treatment of glass panels shall be consistent throughout the system.

3.4.8 Metal In-Fill/Guardsa) See NAAMM/NOMMA AMP 555 and AMP 500-2008 Metal Finishing Manual

b) At round end in drilled holes, gaps shall not exceed:Premium Custom Economy

.8 mm [.031”] .8 mm [.031”] 1.6 mm [.063”]

c) Where not in plow and without shoes, gaps shall not exceed:Premium Custom Economy

1.6 mm [.063”] 1.6 mm [.063”] 2.4 mm [.094”]

d) Where in plow, gaps shall not exceed:Premium Custom Economy

1.6 mm [.063”] 1.6 mm [.063”] 2.4 mm [.094”]

e) Where applicable, powder coating or paint coverage shall be complete over the specified area. Slight surface or edge contour irregularity is acceptable with no evidence of grinding or gouging, and:



Premium Custom EconomyNicks and blemishes are not permitted

Nicks and blemishes are not permitted

Minimal nicks or blemishes are permitted

f) Metal in-fill balusters with shoes shall have:Premium Custom Economy





g) Metal in-fill balusters without shoes shall be:Premium Custom Economy

Mortised to fit ends Mortised to fit ends At the option of the manufacturer/supplier

3.4.9 Well-Hole Trima) Outside corners shall be mitered.

b) Moulded components at inside corners shall be:Premium Custom Economy

Coped Coped Mitered or coped

c) S4S at inside corners shall be butted.

d) Joinery of well-hole trim requires:Premium Custom Economy

Exposed trimmed ends shall be miter returned

Exposed trimmed ends shall be profiled or miter returned

Exposed trimmed ends at the option of the installer

Multiple joints in running trim shall not be within 1219 mm [48”] of another joint in the run, including corners



e) Fasteners and fastening include the use of finish nails, trim screws, staples, pins, and/or construction adhesive for inconspicuous fastening. Staples with a crown exceeding 4.8 mm [.188”] wide are not permitted.

f) Exposed fasteners shall be inconspicuous.

g) Exposed fasteners shall be countersunk through the exposed material surface, kept to a minimum, and shall be:

Premium Custom EconomySet in quirks and reliefs where possible

Set in quirks and reliefs where possible

Fastened in placement at the option of the installer

3.4.10 Nosing, Well-Holea) Nosing of landing tread, at the exit of a flight, shall be made to match the thickness,

profile, and projection of the treads throughout stair.

21


Requirements, FabricationRevised January 14, 2020 3:44 PM

3.4.11 Staircase (Assembled Unit)3.4.11.1 Stairs, Open-Cut Stringer

a) Stairs at open-cut stringers shall:Premium Custom Economy

Be mitered to risers. Be mitered to risers. Attachment of risers at the option of the manufacturer/supplier

Have tread return nosing applied with no visible fastener

Have tread return nosing applied

Have application of tread nosing at the option of the manufacturer/supplier

Have end of tread return returned with no end grain visible

Have end of tread return profiled. End grain is permitted

Have profile or return of tread at the option of the manufacturer/supplier

b) Brackets at open-cut stringers shall be mitered to risers.

c) Tread returns shall be cut to eliminate end grain at the front edge.

3.4.11.2 Stairs, Open-Closed Stringera) At closed stringers:

Premium Custom EconomyTreads and risers shall be mortised into stringers

Treads and risers shall be mortised into stringers Butt joints are permitted

b) Knee walls shall be capped.

3.4.11.3 Stairs, Closeda) At closed stringers:

Premium Custom EconomyTreads and risers shall be mortised into stringers

Treads and risers shall be mortised into stringers Butt joints are permitted

3.5 Fabrication3.5.1 Fabrication, Shop Assembled Stairs

a) Mechanical fasteners, except for nails, at exposed faces shall be concealed.

3.5.1.1 Stringers, Mortiseda) Mortise depth shall be a minimum of 6.1 mm [.250”] to facilitate securing of the

wedge, tread, and/or riser, as applicable (See Figure 97-A).

b) At open mortised (wedged) stringers, tread/riser/stringer joint gap shall be a maximum of .4 mm [.016”]. Gaps shall not exceed 20 percent of the joint perimeter (See Figure 97-B).

c) At nosing, joint gap shall be a maximum of .8 mm [.031”] (See Figure 97-C).

d) Treads and risers that are mortised into open mortised stringers shall be secured with wedges, glue, and/or mechanical fasteners (See Figure 97-D).


22 Requirements, FabricationRevised January 14, 2020 3:44 PM

e) At closed mortise (no wedge) stringers, tread/riser/stringer joint gap shall be (See Figure 97-E):

Premium Custom EconomyA maximum of .4 mm [.016”]

A maximum of .8 mm [.031”]

A maximum of 1.2 mm [.047”]

f) Treads and risers that are mortised into closed mortised stringers shall be secured with glue and mechanical fasteners (See Figure 88).

3.5.1.2 Stringers, Open Cuta) Shall be fastened to underside of treads with glue blocks and/or pocket screws.

b) Shall be mitered to risers with no visible end grain and no gap in the miter joints.

c) At risers with transparent finish, miter joints shall be glued and fasteners shall be concealed whenever possible.

3.5.1.3 Laminated Stringersa) At transparent finish, all visible laminations shall be of matching species or

covered with matching veneer.

3.5.1.4 Stringer Transitionsa) Shall allow for continuation, return, or termination of base cap (See Figure 100).

3.5.1.5 Risersa) At transparent finish, all visible laminations shall be of matching species or


b) Tread/top and bottom of riser joint gap shall be:Premium Custom Economy

Not permitted A maximum of .4 mm [.016”]


c) Where scotia is used, gap tolerance shall be measured between tread and scotia.

d) Shall be secured to the trailing of the tread with mechanical fasteners.

e) Shall be secured to the leading edge of the tread with mechanical fasteners and/or glue blocks.

3.5.1.6 Treadsa) At open cut stringers, tread ends shall be returned in accordance with section

3.4.11.1 Stairs, Open-Cut Stringer.

b) At open rise stairs, plank treads shall be in accordance with section 3.4.3.3 Treads, Plank (Slab).

c) Shall be secured to stringers and risers with mechanical fasteners, wedges, and/or glue blocks.

3.5.1.7 Stair carriages (concealed stringers)a) Where required shall be securely fastened to the staircase assembly.

23


Requirements, Installation Revised January 14, 2020 3:44 PM

b) Shall have a scribe allowance for direct attachment to the structure.

3.5.2 Fabrication, Field Assembled Stairsa) Field assembled stairs shall be fabricated and assembled to meet all of the material

and structural requirements set forth within this standard.

b) Aesthetic tolerances and installation requirements for field assembled stairs shall be as indicated in section 3.6.1 Field Assembled Stair Components.

3.6 Installation a) The following requirements shall govern unless a project’s contract documents require

otherwise.

b) Installer shall obtain, review, and comply with manufacturer/supplier’s documented instructions for installation. Product and components shall be installed per manufacturer/supplier’s documented instructions. When contract documents conflict with documented instructions, installer shall obtain written directives from appropriate parties prior to proceeding with installation.

c) Prior to commencement of installation, installer shall confirm the presence of wood blocking or metal strapping as indicated in contract documents. Installer shall confirm that field conditions and dimensions, including the elevation of landings and floors, are as indicated in the contract documents. If documented conditions are not met, installer shall obtain written directives from appropriate parties prior to proceeding with installation.

d) It is not the responsibility of the installer to scribe or fit to walls, ceilings, floors, or openings whose plumb, level, flat, straight, or square values exceed tolerances specified in contract documents. Where not specified in contract documents, tolerances stated in section 3.1.4 A) Manufacturer/Supplier Requirements for Installation shall apply.

e) The types of joinery used shall be consistent throughout the project.

f) Drywall and bugle head screws are not permitted for the installation of Product.

g) Installation shall comply with the Product’s aesthetic grade as specified in the contract documents.

h) Product shall be installed plumb and level within 3.2 mm [.125”] in 2438 mm [96”].

i) When factory-finished Product is cut or modified to facilitate installation, the resulting unfinished core shall be sealed prior to installation.

j) Tolerances listed for gaps and flushness apply to Product as installed.

k) Unless otherwise indicated within this standard, Product shall be installed free of open joints, visible machine marks, cross sanding, tear-outs, nicks, chips, scratches, layout lines, pencil lines, and/or natural defects exceeding the quantity and/or size limits defined in the AWI 300 - Materials Standard.

l) Residual marks, including adhesive and filler residue on exposed or semi-exposed faces, shall be removed.

m) Areas of installation shall be left broom clean. Debris shall be removed and disposed of in containers provided by the contractor or construction manager.


24 Requirements, Installation Revised January 14, 2020 3:44 PM

n) Plank (slab) platforms shall be in accordance with 3.2.3 and installed in such a way as to permit expansion and contraction.

o) Tolerances for running trim not specified below shall be in accordance with the general tolerances indicated in AWI 0620 - Finish Carpentry/Installation.

3.6.1 Field Assembled Stair Componentsa) Gap tolerances between exposed skirtboards, treads, and risers shall not exceed:

Premium Custom Economy.8 mm [.031”] 1.2 mm [.047”] 1.6 mm [.063”]

b) Concealed stringer fasteners to wall shall be located no less than 50.8 mm [2”] from the bottom edge and no more than 610 mm [24”] on center measured horizontally.

3.6.1.1 Routed Stringers, Field Assembleda) Shall be securely fastened to the building structure with fasteners that are not

subject to withdrawal.

b) Where fastened to wall, shall be fastened to wall no more than 610 mm [24”] on center measured horizontally.

c) Treads and risers that are mortised into stringers shall be secured with wedges, glue, and/or mechanical fasteners.

d) At open mortised (wedged) stringers, tread/riser/stringer joint gap shall be a maximum of .4 mm [.016”].

e) At nosing, joint gap shall be a maximum of .8 mm [.031”].

f) Mortise depth shall be a minimum of 6.1 mm [.250”] to facilitate securing of the wedge, tread, and riser.

g) At closed mortise (no wedge) stringers, tread/riser/stringer joint gap shall be (See Figure 88):

Premium Custom EconomyA maximum of .4 mm

[.016”]A maximum of .8 mm

[.031”]A maximum of 1.2 mm

[.047”]

3.6.1.2 Open Cut Stringersa) Shall be fastened to underside of treads with glue blocks and/or pocket screws.

b) Shall be mitered to risers with no visible end grain and no gap in the miter joints.

c) At risers with transparent finish, miter joints shall be glued and fasteners shall be concealed whenever possible.

3.6.1.3 Laminated Stringersa) At transparent finish, all visible laminations shall be of matching species or


3.6.1.4 Stringer Transitionsa) Shall allow for continuation, return, or termination of base cap (See Figure 100).

25



3.6.1.5 Risersa) At transparent finish, all visible laminations shall be of matching species or


b) Tread/top and bottom of riser joint gap shall be:Premium Custom Economy

Not permitted A maximum of .4 mm [.016”]


c) Gap tolerance shall be measured between tread and scotia when scotia is used.

d) Shall be secured to the trailing of the tread with mechanical fasteners.

e) Risers shall be secured to the leading edge of the tread with mechanical fasteners and/or glue blocks.

3.6.1.6 Treadsa) At open Cut Stringers, ends shall be returned in accordance with section 3.4.11.1

Stairs, Open-Cut Stringer.

b) At Open Rise Stairs, plank treads shall be in accordance with section 3.4.3.3 Treads, Plank (Slab).

c) Shall be secured to stringers and risers with mechanical fasteners, wedges, and/or glue blocks.

3.6.1.7 Stair carriages (concealed stringers)a) Where required, stair carriages shall be securely fastened to the staircase

assembly.

b) Shall have a scribe allowance for direct attachment to the structure.

3.6.2 Stairs, Shop Assembleda) Stair units shall be wrapped to protect stringer, riser, and tread exposed surfaces

from handling and jobsite traffic when installation prior to application of wall finish is required.

b) Temporary stairs shall be provided as contracted when shop fabricated stair units are installed with the finish trim.

3.6.2.1 Attachment to the Structure/Stringers, Concealeda) Stringers shall be securely fastened to the building structure with fasteners that

are not subject to withdrawal. When installed prior to wall finish, stringers shall be shimmed off the framing as required.

b) Fasteners to wall shall be located no less than 50.8 mm [2”] from the bottom edge no more than every 610 mm [24”] on center measured horizontally. Fasteners at exposed faces shall be concealed.

c) Ends of stringers shall be supported by the floor structure so as to prevent splitting using ledgers and/or mechanical connectors as necessary. The ends of stringers not supported by walls shall be connected to prevent rotation at the connection.



d) The top and bottom riser of the flight shall be positioned to be the same height as the other risers of the flight with the landing tread flush with the finished floor at the top of the flight.

e) Multiple flights in a stairway shall be positioned to align with the structure and any guard and/or handrail requirements in accordance with the shop drawings.

3.6.3 Guard and Handrail Installationa) Product shall be installed in accordance with structural and aesthetic requirements set

forth within this standard. (See section 3.3 Structural through section 3.4.11.3 Stairs, Closed)

b) Guards or handrails shall be fastened to remain secure and prevent compression of wall finish material (e.g. gypsum wallboard, drywall, etc.)(See Figure 99).

3.6.3.1 Newelsa) At connections to stair components other than rails, gaps shall not exceed:


b) At newel to rail, gaps shall not exceed 20 percent of the joint perimeter and shall not exceed:


3.6.3.2 Handrailsa) All rail to rail and rail to fitting joints shall be sanded and/or sculpted for seamless

profile alignment to the following flushness tolerances:Premium Custom Economy

.4 mm [.016”] .4 mm [.016”] .8 mm [.031”]

b) At rail to newel (or rosette, or wall), rail to rail, rail to fitting, gaps shall not exceed 20 percent of the joint perimeter and shall not exceed:


c) Plugs at joints are permitted provided they are sanded flush and of compatible color, grain, and grain direction.

3.6.4 Fittings3.6.4.1 Fittings, Transparent Finish

a) Grain and color shall match as specified and, if not specified:Premium Custom Economy

Grain and color shall be well-matched

Grain and color shall be compatible Color shall be compatible

27



b) Finger joints are:Premium Custom Economy


c) Flush plugs at joints are permitted where grain and color are matched to the adjacent surface and sanded flush.

d) Visible fasteners are not permitted unless specified.

e) Countersunk metal splines are permitted, provided the slots have been filled and sanded flush.

3.6.4.2 Fittings, Opaque Finisha) At opaque finish, fittings shall be close-grained wood.

b) Flush plugs at joints are permitted where sanded flush.

c) Visible fasteners are not permitted unless specified.

d) Countersunk metal splines are permitted, provided the slots have been filled and sanded flush.

3.6.5 Guard, In-Fill3.6.5.1 Wood Balusters and Wood In-Fill Joinery, Transparent and Opaque

Finisha) At round end (no shoulder) in drilled holes, gaps shall not exceed:


b) At round or square end (with shoulder), where not in plow, gaps shall not exceed:Premium Custom Economy

.4 mm [.016”] .8 mm [.031”] .8 mm [.031”]

c) At square end in plow with fillet, gaps shall not exceed:Premium Custom Economy

.8 mm [.031”] .8 mm [.031”] 1.6 mm [.063”]

d) All joints in wood in-fill panels and panel systems shall be smooth and flush.

3.6.5.2 Balusters and Newels, Metala) (Shall be in accordance with NAAMM/NOMMA AMP 555 and AMP 500-2008 Metal

Finishing Manual)

b) Metal balusters and newels with shoes shall have:Premium Custom Economy








c) Metal balusters and newels without shoes shall be:Premium Custom Economy




3.6.5.3 Cable In-Filla) Exposed cable ends are not permitted.

b) All sections of cable in-fill shall be tensioned equally.

c) Where cables pass through wood posts at vertical or horizontal transitions, post protectors shall be used.

d) Spreader bars shall be spaced equally and securely fastened.

e) Bushings shall be used to isolate reactive materials and prevent electrolysis.

3.6.5.4 Glass In-Fill/Guardsa) Hardware and glass for glass infill/guards shall be installed per manufacturer/

supplier’s specifications.

b) Glass used for in-fill shall be in accordance with ANSI Z97.1 (Latest Edition) and ASTM C1036 (Latest Edition) Standard Specification for Flat Glass.

3.6.5.5 Metal In-Fill/Guardsa) (Shall be in accordance with NAAMM/NOMMA AMP 555 and AMP 500-2008 Metal

Finishing Manual)b) At round end in drilled holes, gaps shall not exceed:


c) Where not in plow and without shoes, gaps shall not exceed:Premium Custom Economy

1.6 mm [.063”] 1.6 mm [.063”] 2.4 mm [.094”]

d) Where in plow, gaps shall not exceed:Premium Custom Economy

1.6 mm [.063”] 1.6 mm [.063”] 2.4 mm [.094”]

e) Metal in-fill balusters with shoes shall have:Premium Custom Economy




29





f) Metal in-fill balusters without shoes shall be:Premium Custom Economy




3.6.5.6 Well-Hole Trima) Outside corners shall be mitered.

b) Moulded components at inside corners shall be:Premium Custom Economy

Coped Coped Mitered or coped

c) S4S at inside corners shall be butted.

d) Joinery of well-hole trim requires:Premium Custom Economy

Exposed trimmed ends shall be miter returned

Exposed trimmed ends shall be profiled or miter returned

Exposed trimmed ends at the option of the installer




e) Fasteners and fastening include the use of finish nails, trim screws, staples, pins, and/or construction adhesive for inconspicuous fastening. Staples with a crown exceeding 4.8 mm [.188”] wide are not permitted.

f) Exposed fasteners shall be inconspicuous.

g) Exposed fasteners shall be countersunk through the exposed material surface, kept to a minimum, and shall be:

Premium Custom EconomySet in quirks and reliefs where possible

Set in quirks and reliefs where possible

Fastened in placement at the option of the installer

3.6.5.7 Nosing, Well-Holea) Landing tread shall be installed flush with flooring at all flight exits.

b) Shall be installed in accordance with approved shop drawings.


30 Figures / IllustrationsRevised January 14, 2020 3:44 PM

Figure 88 - Gap, Tread and String

Figure 89 - Hybrid Tread

4.0 Figures / Illustrations

AB

CD

31


Figures / IllustrationsRevised January 14, 2020 3:44 PM

Figure 90 - Maximum Angle, Cross Grain Prevention

Figure 91 - Plan View, Curved Handrail, Solid Block



Figure 92 - Grain Orientation, Handrail Easing

Figure 93 - Grain Orientation, Fitting Miter

Level Quarterturn

Quarterturn Cap

33



Figure 94 - Grain Orientation, Fitting/Rail Joint

Figure 95 - Grain Orientation, Volute/Turnout



Figure 96 - Grain Orientation, Easing Glue Lines

Figure 97

B

Gap B

Gap B

Gap C

35



Figure 99

blocking

studsame thicknessas wall surface

Figure 98 - Grain Orientation, Spiral Treads

Premium / Custom Custom / Economy



Figure 100 - Concept

37


Supplemental InformationRevised January 14, 2020 3:44 PM

5.0 Supplemental Information5.1 Exceptions to Material Requirements

a) The following species are subject to the requirements of sections 3.2 through 3.2.11.1 unless otherwise indicated in the tables below: Alder (Red), Anigre, Ash (White), Basswood, Beech (American), Beech (European), Birch (Yellow – natural), Birch (Yellow - select red), Birch (Yellow - select white), Cedar (Western Red), Cherry (American Black), Fir (Douglas - flat grain), Fir (Douglas - vertical grain), Hickory (True Group), Mahogany (African - plain sawn), Mahogany (African - quarter sawn), Mahogany (American), Makore, Maple (Hard – natural), Maple (Hard - select white), Maple (Soft – natural), Oak (English Brown), Oak (Red - plain sawn), Oak (Red - rift sawn), Oak (Red - quarter sawn), Oak (White - plain sawn), Oak (White - rift sawn), Oak (White - quarter sawn), Pecan Group (Hickory), Pine (Eastern or Northern White), Pine (Ponderosa), Pine (Southern Yellow), Pine (Sugar), Poplar (Yellow), Redwood (flat grain heartwood), Redwood (vertical grain heartwood), Teak, Jatoba, Sapele, and Walnut (American Black).

WOOD SPECIES EXPOSED STRINGERS & SKIRT BOARDSMaximum Number of Staves

Per 12” WidthPremium Custom Economy

Cherry, American Black 4 S SOak, English Brown 4 S SOak, Red - rift sawn 4 S SOak, Red - quarter sawn 4 S SOak, White - rift sawn 4 S SOak, White - quarter sawn 4 S SPecan Group, Hickory 4 S SWalnut, American Black 4 S S*S - Requirements set forth in AWI/SMA 0643 - Wood Stair, Handrail, and Guard Systems (Current Edition) shall apply

WOOD SPECIES EXPOSED STRINGERS AND SKIRTBOARDS

Number of Linear Splices in Staves up to 14’

Minimum Length

of Stave Where

One-Piece Stave is Required

Premium Custom Economy All GradesAlder, Red 1 1 Unlimited 10’Anigre 1 1 Unlimited 12’Ash, White 1 1 Unlimited 12’Basswood 1 1 Unlimited 10’Beech, American 1 1 Unlimited 12’Beech, European 0 0 Unlimited 15’6”Birch, Yellow - natural 1 1 Unlimited 12’Birch, Yellow - select red 1 1 Unlimited 11’


38 Supplemental InformationRevised January 14, 2020 3:44 PM

WOOD SPECIES EXPOSED STRINGERS AND SKIRTBOARDS

Number of Linear Splices in Staves up to 14’

Minimum Length

of Stave Where

One-Piece Stave is Required

Premium Custom Economy All GradesBirch, Yellow - select white 1 1 Unlimited 11’Cedar, Western Red 0 0 Unlimited 15’6”Cherry, American Black 1 2 Unlimited 7’Fir, Douglas - flat grain 0 0 Unlimited 15’6”Fir, Douglas - vertical grain 0 0 Unlimited 15’6”Hickory, True Group 1 1 Unlimited 12’Mahogany, African - plain sawn 0 0 Unlimited 15’Mahogany, African - quarter sawn 0 0 Unlimited 15’

WOOD SPECIES RAILMinimum Length of Rail where

Solid Top Cap is RequiredPremium Custom Economy

Alder, Red 10’ 8’ SAnigre 12’ 10’ SAsh, White 12’ 10’ SBasswood 12’ 10’ SBeech, American 12’ 10’ SBeech, European 15’6” 14’ SBirch, Yellow - natural 12’ 10’ SBirch, Yellow - select red 11’ 10’ SBirch, Yellow - select white 11’ 10’ SCedar, Western Red 15’6” 14’ SCherry, American Black 8’ 6’ 4’Hickory, True Group 12’ 10’ 8’Makore 12’ 10’ 8’Oak, English Brown 8’ 6’ 4’Oak, Red - rift sawn 10’ 8’ 4’Oak, Red - quarter sawn 10’ 8’ 4’Oak, White - rift sawn 10’ 8’ SOak, White - quarter sawn 10’ 8’ STeak 10’ 8’ 4’Walnut, American Black 8’ 6’ 4’*S - Requirements set forth in AWI/SMA 0643 - Wood Stair, Handrail, and Guard Systems (Current Edition) shall apply

39


Supplemental InformationRevised January 14, 2020 3:44 PM

WOOD SPECIES RAILMaximum Permitted Joints in Top Laminate of

Rail Per 15’ - 6” LengthPremium Custom Economy

Alder, Red 1 1 SAnigre 1 1 SAsh, White 0 1 SBasswood 0 1 SBeech, American 0 1 SBeech, European 0 1 SBirch, Yellow - natural 0 0 SBirch, Yellow - select red 0 0 SBirch, Yellow - select white 0 0 SCedar, Western Red 0 0 SCherry, American Black 1 1 SFir, Douglas - flat grain 0 0 SFir, Douglas - vertical grain 0 0 SHickory, True Group 1 1 SMahogany, African - plain sawn 0 1 SMahogany, African - quarter sawn 0 1 SMahogany, American 0 0 SMakore 1 2 SMaple, Hard - natural 0 1 SMaple, Hard - select white 0 1 SMaple, Soft - natural 0 1 SOak, English Brown 1 1 SOak, Red - plain sawn 0 1 SOak, Red - rift sawn 1 1 SOak, Red - quarter sawn 1 1 SOak, White - plain sawn 0 1 SOak, White - rift sawn 1 2 SOak, White - quarter sawn 1 2 SPecan Group, Hickory 1 2 SPine, Eastern or Northern White 0 1 SPine, Ponderosa 0 1 SPine, Southern Yellow 0 1 SPine, Sugar 0 1 SPoplar, Yellow 0 1 SRedwood, flat grain heartwood 0 0 SRedwood, vert. grain heartwood 0 0 STeak 0 1 SJatoba S S SSapele S S S


40 Supplemental InformationRevised January 14, 2020 3:44 PM

WOOD SPECIES RAILMaximum Permitted Joints in Top Laminate of

Rail Per 15’ - 6” LengthPremium Custom Economy

Walnut, American Black 1 2 S*S - Requirements set forth in AWI/SMA 0643 - Wood Stair, Handrail, and Guard Systems (Current Edition) shall apply

WOOD SPECIES TREADMaximum Number of Staves

Per 12” DepthPremium Custom Economy

Oak, Red - rift sawn 4 5 SOak, Red - quarter sawn 4 5 SOak, White - plain sawn S S SOak, White - rift sawn 4 5 SOak, White - quarter sawn 4 5 STeak 4 5 SWalnut, American Black S 5 S*S - Requirements set forth in AWI/SMA 0643 - Wood Stair, Handrail, and Guard Systems (Current Edition) shall apply

WOOD SPECIES RISERNumber of Staves Per 7.75” Height

Premium Custom EconomyOak, English Brown 3 3 SWalnut, American Black 3 3 S*S - Requirements set forth in AWI/SMA 0643 - Wood Stair, Handrail, and Guard Systems (Current Edition) shall apply

awi/sma standard for wood stair, handrail, and guard systems · a) provides standards for the...

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