WARNINGFailure to complete items below prior to inspection may result in a re-inspection fee.

NOT ALLOWED As of January 1, 2008, per CBC 2509.2 all paperbacked gypsum board products such as “Green board”, “Purple board”, & “Mold Resistance board” is prohibited in shower & tub compartments & shall not be used as a backer for tile lath or concrete.

Water-Resistant gypsum board shall NOT be used in the following locations. CBC 2509.3

1. Over vapor retarder. 2. In shower or bathtub compartments. 3. In areas subject to continuous high humidity, such as saunas, steam or gang showers. 4. On ceilings where frame spacing exceeds 12” on center for 1⁄2” wall board & more than 16” on center for 5/8” water-resistant drywall. (NOTE: Per OMC Section 15.04.678 as backing board for glue-on thinset tile.)

ALLOWAbLE INsTALLATIONs pER OMC sECTION 15.04.678The following typical installations for walls in showers & water closets are acceptable pursuant to this section. All of the following finishes shall extend a minimum of 70 in. above the adjacent tub or shower drain. Joint & nail treatment & installa-tion shall be pursuant to specific manufacturer’s installation instructions.

1. Marble Finisha. No building paper on stud face.b. Water-resistant gypsum backing board with nailing inspection required.c. Glued-on marble or marble equivalent

2. Thinset & Glue-on Tilea. Building paper on stud face.b. Cementitious backer unit (CBU) installed in accordance with manufacturer’s instructions. Instructions on jobsite

at time of inspection.c. Tile (thinset or glue-on).d. Finish grout.

3. Tilea. No building paper on stud face.b. Water-resistant gypsum backer board (greenboard).c. Paper/lath with inspection requiredd. Scratch coate. Tile installationf. Finish grout

4. Fiberglass kits (does not include solid one-piece units) which have been approved by I.A.P.M.O. (or other approved testing & listing agency) for use in tub/shower walls

a. No building paper on stud face.b. Water-resistant gypsum backer board (greenboard) with inspection required.c. Fiberglass kit installation per manufacturer’s instructions with instructions available to inspector on the jobsite.

shower Wall Guidelines

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sHOWER & TUb COMpARTMENT AppROVED TILE bACKER METHODs

Method 1. Fiberglass Mat Backer Board (DensShield®, GlasRoc® Tile Backer) Do not install a water-resistive vapor barrier behind Fiberglass Mat Backer Board. Joints shall be sealed with flexible sealant.

Method 2. Cement & Fiber-cement Backer Boards (HardieBacker® 500, Durock®) A water-resistive vapor barrier is required behind cement board (min. Grade B paper) Joints shall be taped (follow manufacturers’ instructions.

Method 3. Mortar backed (lath & plaster) A water-resistive vapor barrier is required behind lath (min. Grade B paper)

REQUIRED INspECTIONs1. Screw inspection for tile backer board

2. Water barrier & lath inspection When possible combine shower pan inspection with tile lath Inspection.

TILE LATH INspECTION☐ Showers in all occupancies shall be finished to a height of not less than 70” above the drain inlet. CBC 1115 B.2

☐ Shower & tub compartment tile backer shall be installed in accordance with manufacturer recommendations CBC 2509.2

☐ Water-resistive barriers shall include a minimum one layer of Grade B paper & shall be applied horizontally, with the upper layer lapped over the lower layer not less than 2”. Where vertical joints occur, felt or paper shall be lapped not less than 6”. Surfaces exceeding 45 degrees from vertical shall have barriers of class B or better. We recommend products similar to ice & water shield in these areas as they are frequently leakage points. CBC 2506.4, 1402.1

Lath (20 gage), Lath Fasteners, & Attachments

☐ Lath (20 gage), lath fasteners, & attachments shall be corrosion resistant materials. CBC 2510.4

☐ Fasteners such as Durock screws or hot dipped galvanized screws shall be used per manufacturer’s specifications. CBC 2507.1 Note: NOT for Lath

☐ Lath fasteners shall be 11 gage furring nails &/or waferhead screws

☐ Attachments shall be made at framing members. CBC 2510.5.1 Lath fasteners to wood framing members shall be verti-cally spaced 8” & horizontally spaced 16” min. Staples 8” on center may be used with self furring lath only.

☐ Showers: Materials other than structural elements used in such walls shall be of a type that is not adversely affected by moisture. Metal or wire Lath shall be applied with the long dimension of the sheets perpendicular to supports.

☐ Metal Lath shall be lapped not less than 1⁄2” at sides & 1” at ends.

☐ Wire lath shall be lapped not less than one mesh at sides & ends, but not less than 1”. Overlap round corners 12”. CBC 2505.3

☐ Metal & wire lath shall be furred out away from vertical supports at least 1⁄4”. Self furring lath shall meet furring requirements.

☐ Caulk or foam seal around plumbing fixture penetrations. We recommend caulking at transition between bathtub & shower pan. Verify that windows less than 60” inches above drain shall be tempered glass, not wood. Exception: Glass blocks. ORC R308.4 Page 2 of 3

shower Wall Guidelines

shower Wall Guidelines

Fix for green/purple/mold resistant board in shower & tub compartment:

1. Remove non compliant materials & replace with approved materials

OR

2. Apply approved liquid membrane i.e. RedGard®, HTM 4000, etc... over non compliant board.

3. Pay the re-inspection fee & schedule inspection.

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