Section 1519 High-Velocity Hurricane Zones—Roof Coverings With Slopes Less Than 2:12

All adhered roofing components shall be bonded to the various types of substrates in compliance with the requirements set forth in the roofing assembly product approval and the following minimum requirements. The authority having jurisdiction may adopt RAS 150 as the means of complying with the requirements listed in this section.

All packaged asphalt shall have the following data printed on the carton wrapper:

ASTM designation and type;

Flash point as determined by ASTM D92, Flash and Fire Point by Cleveland Open Cup; and

Equiviscous temperature (EVT) at which the asphalt attains a viscosity of 125 centipoise (25 centipoise for coal tar) as determined by ASTM D4402, Viscosity Determinations of Unfilled Asphalt Using the Brookfield Thermoset Apparatus.

Back nailing of interply sheets shall not be required when using ASTM D312 Type IV asphalt on slopes less than 3:12.

All mechanically attached roofing components shall be attached to the various types of substrates in compliance with the requirements set forth in the roofing assembly product approval and the following minimum requirements.

Nails shall be minimum 12 gage, annular ring shank nails having not less than 20 rings per inch; heads not less than ³/₈ inch (9.5 mm) in diameter; and lengths sufficient to penetrate through the thickness of plywood panel or wood plank decking not less than ³/₁₆ inch (5 mm), or to penetrate into a 1-inch (25.4 mm), or greater, thickness of lumber not less than 1 inch (25.4 mm). Nails shall be hot dipped; electro- or mechanically galvanized to a thickness sufficient to resist corrosion in compliance with Appendix E of TAS 114. All nails shall have product approval. All nail cartons or carton labels shall be labeled to note compliance with the corrosion-resistance requirements. No roofing material shall be fully or partially adhered, unless otherwise noted in the roof assembly product approval directly to a nailable deck.

Where the architectural appearance of the underside is to be preserved, a base sheet may be secured in an alternate method of attachment prepared, signed, and sealed by a Florida-registered architect or engineer, or in buildings where the mean roof height does not exceed 15 feet (4.6 m), a base sheet may be secured with 1¹/₄-inch (32 mm) fasteners on supporting members, with a minimum of ¹/₂-inch (12.7 mm) fasteners between the supporting members, all of which shall be secured through tin caps and nailed 6 inches (152 mm) o.c. in all directions.

All lightweight insulating concrete shall be vented per roofing system manufacturer recommendations.

The mechanical attachment of roofing components to other nailable decks shall be governed by the roofing assembly product approval.

Cast-in-place and precast structural concrete decks are considered nonnailable. Concrete decks shall be clean, dry and fully primed with ASTM D41 or ASTM D43, as required, primer applied at a rate of not less than 1 gallon (3.8 L) per square. Hot asphalt or cold adhesive shall not be applied until the primer has fully dried.

Steel decks shall be covered with a roof insulation panel having its own product approval and listed in the roofing assembly product approval. Insulation panels shall be mechanically fastened in compliance with the mechanical attachment patterns listed in the roofing assembly product approval and in accordance with the provisions of RAS 117.

If the deck thickness on an existing steel deck is less than 22 gage, a field fastener withdrawal-resistance test shall be conducted in compliance with TAS 105 to confirm compliance with the wind load requirements of Chapter 16 (High-Velocity Hurricane Zones). Test results shall be submitted with the uniform roofing permit application for review prior to issuance of the roofing permit. The field fastener withdrawal-resistance test shall be carried out by an approved testing laboratory.

Steel decks shall be welded or mechanically attached to the structure in compliance with the design pressure requirements set forth in Chapter 16 (HighVelocity Hurricane Zones).

Composite wood and insulation panels shall be mechanically attached to steel decks in compliance with the attachment requirements enumerated in the insulation roofing component product approval. The composite wood insulation panel shall be in compliance with the minimum sheathing requirements of this code.

All flashing shall be installed according to the roof assembly manufacturer's published details and literature and in accordance with RAS 111.

Valleys in BUR shall be installed according to the roof assembly manufacturer's published literature for high wind areas and in compliance with the applicable detail described in the product approval.

All parapet wall details shall be installed in accordance with the roofing system product approval, manufacturer's published details and literature and in accordance with approved methods detailed in RAS 111.

Roof insulation shall be applied in compliance with the roofing system product approval and RAS 117.

Roofing assemblies shall be surfaced in compliance with the product approval. Surfacing shall be in sufficient quantity to comply with the required fire classification. Aggregate surfacing shall not be used on slopes greater than 3:12. Aggregate shall be embedded in a flood coat of bitumen applied over a prepared top ply.

On slopes of 3:12 or less, not less than 400 pound (182 kg) of roofing gravel or 300 pounds (145 kg) of slag per square shall be applied. A minimum of 50 percent of the total aggregate shall be embedded in the flood coat of bitumen. Aggregate shall be dry and free from dirt and shall be in compliance with the sizing requirements set forth in ASTM D1863. A building official may request a test to confirm compliance with these requirements.

On inclines greater than 3:12, a smooth surface coating shall be applied.

Mineral surfaced cap sheet applications shall not require any additional surfacing unless required with the particular assembly for a fire classification.

All smooth surface applications shall be coated with an aluminized or emulsion coating, having a valid and current product approval and shall be in compliance with the application instructions in said product approval. Coating quantity shall be in compliance with the required fire rating classification for the structure.

All edge metal and terminations shall be installed according to manufacturer's published literature, provided it meets the minimum requirements as set forth in RAS 111 and Chapter 16 (HighVelocity Hurricane Zones).

Expansion joint covers and expansion joint components shall be constructed and installed in accordance with the roofing assembly manufacturer's published literature.

All roof assemblies shall be applied to a dry substrate. Vapor retarders shall be installed, where applicable, to reduce moisture vapor flow into insulation from the warm, humid building interior, leading to internal condensation. Vents shall be installed to assist in the expulsion of moisture vapor where such vapor may enter the roofing assembly or moisture, as defined in Section 1521.12. Venting units shall not allow vapor to enter the roofing assembly when the high vapor pressure side is above the roofing membrane.

Waterproofing systems may be installed in lieu of an approved roof system over sloped or horizontal decks specifically designed for pedestrian and/or vehicular traffic, whether the deck is above occupied or unoccupied space. In new construction the minimum deck slope shall be ¹/₄:12.

The waterproofing system must possess a current and valid product approval.

If an overburden or wearing surface is not to be installed, the waterproofing system must be approved by the manufacturer for use in vehicular and/or pedestrian traffic locations.

If any portion of the waterproofing membrane is to remain exposed, the waterproofing system shall be ultra-violet resistant.

Flashings must be installed in accordance with the waterproofing manufacturer's published specifications and in compliance with the material and attachment standards of RAS 111.

The waterproofing system shall be flood tested in accordance with ASTM D5957.