ROOF SYSTEMSMoisture Protection

Prepared by: Novee Ralph A. EdictoBSCE V

ANSWER:

Roof

•It is the covering on the uppermost part of a building or shelter.•It provides protection from animals and weather.

Roof Slopes

1. Sloping Roof-  A roof having one or more

surfaces with a slope of atleast 3:12

Types of Sloping Roof

Low-Slope 3:12Medium to High-Slope 4:12 to 12:12

2. Flat Roof- A nearly horizontal roof pitched

for water drainage only.

Parts of a Sloping Roof

Parts of a Sloping Roof

1. Ridge – The highest area of the roof the joins two slopes.2. Flashing – Pieces of metal that is used to prevent the seepage of water at roof intersections.3. Roofing Underlayment –  Roofing underlayment is an additional layer of waterproofing protection.4. Decking/Sheathing – The decking are the wooden panels that cover the rafters and which the roofing materials are attached.5. Valley – The intersection of to sloping roofing panels.6. Joist – Horizontal supporting member of a roof.

7. Gutter – A narrow channel which collects and diverts rainwater away from the roof edge9. Shingles/Cover – roof covering consisting of individual overlapping elements.9. Fascia – Wood used to cover the end of the rafters on the edge of the roof.

Moisture Protection- Most building materials are subject to some degradation by

exposure to moisture. Building systems must be designed to resist the transfer of moisture to the inside of the structure.

- The most common way for moisture to enter a building is in its liquid form. Leaks may occur that allow rain or groundwater to infiltrate the building envelope.

1. Deck- Panels that cover the rafters and to which the roofing material are attached.

2. Underlayment- Provides temporary protection until a roof covering is installed and provides

a secondary weatherproofing barrier. Types of Underlayment

•Asphalt-saturated Felt•Rubberized Asphalt•Non-bitumen Synthetic

3. Roof Cover- The roof covering is the external water-shedding material. Types of Roof Cover

•Wood Shingles and Shakes•Composite Shingles•Tile Roofing•Slate Shingles•Metal Roofs•Corrugated Roof

Sloping Roof System

Types of Underlayment

1. Asphalt-Saturated Felt- One of the most

common types of underlayment.

- Felt underlayment may be made from either organic or fiberglass substrate.

2. Rubberized Asphalt- These typically have

adhesive on one side, which is protected by a peel-off membrane,

making them self-adhering.

3. Non-bitumen Synthetics- Non-bitumen synthetic

underlayments are made from polypropylene or

polyethylene.- Synthetics are

resistant to fungal growth and are wrinkle-

free, since they don’t absorb moisture.

1. Wood Shingles and Wood Shakes- Wood shingles and shakes are

normally cut from red cedar.- Wood shakes are formed by

splitting a short log into a number of tapered radial sections.

- Wood shingles are sawn. - Helps to insulate the attic. - Demands proper maintenance

and repair.- Requires spray-on fire retardants

or pressure treatment to resist fire.

Types of Roof Cover

2. Composite Shingles- Composition shingles have either

an inorganic fiberglass base or an organic felt base surfaced on with colored mineral or

ceramic granules- They are relatively easy to install,

and in some applications can be nailed in place over an existing roof.

- They require low maintenance and can be walked on without damaging the material.

- They can blow off in high winds.

3. Tile Roofing- Tile roofing consists of clay or

concrete units that overlap or interlock to create a strong textural pattern.

- Roofing tiles are fire-resistant, durable, and require little maintenance.

- They are also heavy and require roof framing that is strong enough to carry the weight of the tiles.

- Generally they all have a long lifespan, require low maintenance, offer good fire protection and are resistant to rot and

insects. - Concrete is more expensive than

some roofing materials.

4. Slate Shingles- A fine-grained rock formed by the

metamorphosis of clay, shale, etc., that tends to split along parallel cleavage planes.

- Slate is an extremely durable, fire-resistant, and low maintenance roofing material.

- Have a very long lifespan, good fire protection, low maintenance, and an invulnerably to rot and insects.

- Like tile, slate can be very heavy, sometimes requiring expensive extra support.

- It is breakable enough that walking on it.

- Expensive.

5. Metal Roofing- A sheet metal roof is

characterized by a strong visual pattern of interlocking seams.

- The metal sheets may be of copper, zinc alloy, galvanized steel, or terne metal, a

stainless steel plated with an alloy of tin and lead.

- Metal roofing can be installed over existing roofs.

- Installing some metal roofing can be an intricate process best done by a

professional, and the initial cost of a metal roof is higher than most other roofing materials.

6. Corrugated Roofs- Corrugated or ribbed roofing

panels span between roof beams or purlins running across the slope. The roofing panels may be of:

•Aluminum•Galvanized steel•Fiberglass or reinforced plastic•Corrugated structural glass

- Steel corrugated roofing materials can be quite long lasting. They are also pretty lightweight and easy to handle.

- Corrugated roofing materials that uses fiberglass are very translucent which can provide natural lighting to the house.

1. Build-Up Flat Roofs- A built-up roof, most of the time

referred to as BUR, is a time-tested roofing system typically comprised of roofing felt, hot tar and gravel.

- It is also a very strong roofing system which allows it to be more useful as it can handle more foot traffic and other structures on the roof surface.

Flat Roof Assemblies

2. Modified Bitumen Flat Roofs- Modified Bitumen roofs are single

ply systems that are most often roll-applied to the roof surface.

- Many times, Modified Bitumen roofs are installed by rolling out the roofing material after it has been heated with a blow torch.

3. PVC Roofing System- PVC is a type of single-ply

membrane system. This roofing system is highly reflective and very durable.

- PVC is one of the top flat roof options because it is easy to install and lacks water permeability, meaning it can resist water ponding.

4. EPDM Flat Roofs- EPDM, which stands for Ethylene

Propylene Diene Monomer, is a synthetic rubber derived from oil and natural gas.

- It is a single-ply system that is very similar to PVC, but it is rubber while PVC is plastic.

- Most common single-ply system because of the ease of application and its low cost.

5. Spray-Applied Roof Coating- Specifically, silicone roof coating

systems. - These are the roofing systems

that we apply, and we believe they are the best because of their seamless application (sprayed on), ability to resist ponding water, and reflective

properties.

Roof Drains- Roof drains is a type of drain

installed to receive water collecting on the surface of a roof and to discharge it into a leader,

downspout, or conductor.

For Sloping Roofs  

- Rainwater shed by sloping roofs should be caught by gutters along the eave to prevent ground erosion.

Drainage

For Flat Roofs  

- Flat roofs should be pitched to roof drains that are located at the low points and that connect to the storm drain system of the building. A system of Scuppers or overflow

drains may also be required with the inlet flow 2" above the low points of the roof.

Flashing- Flashing refers to thin

continuous pieces of sheet metal or other impervious

material installed to prevent the passage of water into a structure from an angle or

joint. - Flashing may be exposed or

concealed and may be a sheet metal or water proofing membrane.

Flashing

Thank You!