NAVFAC Design-Build Model Request for Proposal - Test

B30 GENERAL SYSTEM DESCRIPTION

Roof systems shall be watertight and compatible with facility function, construction, and service conditions.  Provide complete roof system design and construction services for the entire new facility roof system, including all ancillary and incidental work necessary for a complete, new, watertight roof system installation.

Submittal Requirements: Components of a minimum roof submittal shall include the roof plan, method of drainage, standard details and details unique to the project, wind load calculations and requirements.

NOTE:  The minimum roof live load will be not less than 20 psf (960 Pa).  Specify here if a greater load is required.

Built-in gutter systems where drainage passes through an interior space or is concealed in the exterior cavity wall shall be prohibited.

Refer to UFC 3-110-03, Roofing, and UFC 3-100-10N, Architecture, for additional roofing requirements.

[The project is an addition to an existing building, and the roof system of the addition shall match the roof of the existing building, which is ______.]

B3010 ROOF COVERINGS

B301001 STEEP SLOPE ROOFING SYSTEMS

Steep slope roofing systems are preferred over low slope roofing systems, where practical.  Steep slope roofing systems that are acceptable include [metal], [slate], [concrete tiles], [clay tiles], and [asphalt shingles].

The roof system shall be designed and attached to resist wind uplift pressures calculated in accordance with ASCE 7.  Uplift resistance shall be validated by applicable Factory Mutual (FM), Underwriters Laboratories (UL) or ASTM uplift resistance test procedures. [Steel panels shall be zinc-coated steel conforming to ASTM A 653/A 653M; aluminum-zinc alloy coated steel conforming to ASTM A 792/A 792M, AZ [55] [50] coating; or aluminum-coated steel.]

[Sub-purlins for the Structural Metal Roof System shall be [galvanized] [shop painted].]

NOTE: For Structural Standing Seam Metal Roofing Systems, specify here the 5-year or the 5-year plus 20-year warranties.

[SSSMRS Warranty Certificate.  At the completion of the project the Contractor shall furnish signed copies of the 5-year Warranty for Structural Standing Seam Metal Roof (SSSMR) System, a sample copy of which is attached to the PTS section [, and the 20-year Manufacturer's Material Warranties, and the manufacturer's 20-year system weather-tightness warranty].

NOTE:  Few manufacturers regularly produce prefinished panels meeting these low gloss requirements and such sheets are available only in limited colors.  Standard 70 percent PVF2 finish, for example, has a medium gloss.  Low gloss paint formulations result in reduced weathering properties.  The project program shall dentify individual facilities requiring low gloss finish.
For roof of structures at airfields where glare would be objectionable and may be an operational hazard, the specular gloss value should be limited to 10 or less at an angle of 85 degrees.

[Specular Gloss of Finished roof surfaces for [_____] shall have a specular gloss value of [10 or less at an angle of 85 degrees] [30 plus or minus [_____] at 60 degrees] when measured in accordance with ASTM D 523.]

B301002 LOW SLOPE ROOFING SYSTEMS

Wind Uplift - The complete roof covering assembly shall be rated Class 1- 60,75,90,105,120,135 or appropriate in accordance with FM P7825, capable of withstanding an uplift pressure of [60] [75] [90] [105[120][135][___]pounds per square foot (with a safety factor of 2) ([1.44] [2.15] [5.8] [__] kPa), and FM I-49 for perimeter and flashing attachment.

NOTE: Specify Class B option only when Class A may not be attainable such as membrane system application directly to wood deck. Provide justification/rationale for Class B option with design submission

 [Fire Safety - Complete roof covering assembly shall:

1. Be [Class [A] [B] rated in accordance with ASTM E 108] [or] [FM 4470] [or] [UL 790]; and 
   
2. Be listed as [part of Fire-Classified roof deck construction in UL RMSD] [or] [Class I roof deck construction in FM P7825c].]

[A three ply modified system consisting of modified base sheet, modified bitumen interply sheet, and modified bitumen cap sheet is the system of choice for new low sloped roofing.]

[Use a ventilating base sheet over any materials which may contain moisture which may need to transpire out of the building.]

Low slope roofing systems that are acceptable include [aggregate surfaced four-ply built-up roofing], [three-ply built-up roofing systems with modified bitumen cap sheet surfacing] [or] [three-ply modified bitumen roofing] [or] [EPDM].

NOTE: Specify the polyester reinforced cap sheet where roof traffic or the other requirements below warrant its use.

[Provide polyester reinforced cap sheet on Modified Bitumen roofs expected to experience high levels of traffic, on roofs with congested equipment, where equipment is expected to receive regular service or high maintenance, and where other service conditions warrant.]

B301003 ROOF INSULATION AND FILL

For fastening roof insulation on low-slope membrane roofs, fasteners shall be place to withstand and obtain an uplift pressure of [60] [75] [90] [105[120][135][___]pounds per square foot (with a safety factor of 2) ([1.44] [2.15] [5.8] [__] kPa) in the field of the roof and FM LPDS 1-49 for perimeter component and flashing attachment. 

B301004 FLASHINGS AND TRIM

Flashing and sheet metal work shall include scuppers, splash pans, and sheet metal roofing.  Flashings shall be [copper, sheet and strip - ASTM B 370, cold-rolled temper] [Lead-Coated Copper Sheet - ASTM B 101] [Lead Sheet - Minimum weight .19 kPa (4 pounds per square foot)] [Steel Sheet, Zinc-Coated (Galvanized) - ASTM A 653/ A 653M.] [Galvanized steel items shall have a baked-on, factory applied finish of polyvinylidene fluoride or an equivalent fluorocarbon coating] [Stainless Steel - ASTM A 167, Type 302 or 304] [Aluminum Alloy Sheet and Plate - ASTM B 209] [Pre-Finished Aluminum. Finish shall be baked-on factory applied color coating of polyvinylidene fluoride (PVF2) or other equivalent fluorocarbon coating with a minimum thickness of 0.8 to 1.3 mils].

B301005 GUTTERS AND DOWNSPOUTS

Provide gutters and downspouts compatible with roofing material and finish. Concealed (interior) gutters and downspouts are prohibited.

NOTE:  Provide roof hatches where required by OSHA, and/or as access to roof when roof mounted equipment is used or other routine roof maintenance is required  Provide skylights or other glazed roof openings only to supplement interior lighting levels. (generally in steep slope or vertical applications), and otherwise, are discouraged from use.  Proper detailing is critical, and shall be scrutinized closely to minimize the likelihood of future leaks at these locations.  Provide guards or rails where required by OSHA or the building code.

B301006 ROOF OPENINGS AND SUPPORTS

Provide [insulated roof hatch] [and] [skylights] [____ glazed roof openings] [and] [rails or guards].

B301090 OTHER ROOFING

[Provide lightning protection, without penetrating the roof membrane or flashing components]

[Reuse existing roof drains with new, compatible flashing materials, a new drain clamping ring and new bolts for anchorage] [Provide new roof drains and accessories] 

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