0-9 SPECS 07416.doc

IDC Base Roof Repair

DIVISION 7 – THERMAL & MOISTURE PROTECTION

SECTION 07550 - MODIFIED BITUMINOUS MEMBRANE ROOFING

PART 1 - GENERAL

1.01 REFERENCES: The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

A. American Society for Testing and Materials (ASTM)

ASTM D 41

(1994) Asphalt Primer Used in Roofing, Dampproofing, and Waterproofing

ASTM D 226

(1995) Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing

ASTM D 312

(1995; Rev. A) Asphalt Used in Roofing

ASTM D 1863

(1993) Mineral Aggregate Used on Built-Up Roofs

ASTM D 2170

(1995) Kinematic Viscosity of Asphalts (Bitumens)

ASTM D 4402

(1987; R 1991) Viscosity Determinations of Unfilled Asphalts Using the Brookfield Thermosel Apparatus

ASTM D 4586

(1993) Asphalt Roof Cement, Asbestos-Free

ASTM D 4601

(1995) Asphalt-Coated Glass Fiber Base Sheet Used in Roofing

ASTM D 4897

(1995) Asphalt-Coated Glass-Fiber Venting Base Sheet Used in Roofing

ASTM E 108

(1995) Fire Tests of Roof Coverings

B. Factory Mutual Engineering and Research Corporation (FM)

FM A/S4470

(1986; R 1992) Class I Roof Covers

FM P7825

(1997) Approval Guide

C. Underwriters Laboratories, Inc. (UL)

UL RMSD

(1997) Roofing Materials and Systems Directory

UL 790

(1995) Fire Resistance of Roof Covering Materials

1.02 SUBMITTALS: Submit the following in accordance with Section 01330, "Submittal Procedures."

A. SD-02 Manufacturer's Catalog Data

1. Modified bitumen sheet G [2. Asphalt]

3. Felts

4. Primer

5. Asphalt roof cement

6. Fasteners

7. Coating

8. Sample warranty certificate G

B. SD-06 Instructions

1. Torches

2. Modified bitumen sheet [3. Asphalt]

4. Felts

5. Primer

6. Asphalt roof cement

7. Fasteners

8. Coating

9. Flashings

10. Cold weather installation

Include detailed application instructions and standard drawings altered as required by these specifications. Explicitly identify in writing, differences between manufacturer's instructions and the specified requirements.

C. SD-08 Statements

1. Qualification of manufacturer

2. Qualification of applicator [3. Bill of lading]

Certify that the manufacturer of the modified bitumen membrane meets requirements specified under paragraph entitled "Qualification of Manufacturer." Show evidence that products used within this specification are manufactured in the United States. Certify that the applicator meets requirements specified under paragraph entitled "Qualification of Applicator." [Submit bill of lading when labels of asphalt containers do not bear the flash point (FP), finished blowing temperature (FBT), and equiviscous temperature (EVT).]

D. SD-18 Records

1. Information card

2. Instructions to Government personnel

a. Written Instructions to Government Personnel: Submit instructions meeting the requirements of paragraph entitled "Instructions to Government Personnel" and include copies of Material Safety Data Sheets for maintenance/repair materials.

1.03

QUALITY ASSURANCE

A. Qualification of Manufacturer: Modified bitumen sheet roofing system manufacturer shall have a minimum of 5 years experience in manufacturing modified bitumen roofing products.

B. Qualification of Applicator: Roofing system applicator shall be approved, authorized, or licensed in writing by the modified bitumen sheet roofing system manufacturer and shall have a minimum of three years experience as an approved, authorized, or licensed applicator with that manufacturer and be approved at a level capable of providing the specified warranty. The applicator shall supply the names and locations of 5 projects of similar size and scope that he has constructed using the manufacturer's roofing products submitted for this project within the previous three years.

C. Fire Safety: Complete roof covering assembly shall:

1. Have ASTM E 108 Class 1A or UL 790, Class A classification; and

2. Be listed as part of Fire-Classified roof deck construction in UL RMSD, or Class I roof deck construction in FM P7825.

3. UL approved components of the roof covering assembly shall bear the UL label.

D. Wind Uplift: Complete roof covering assembly shall be rated Class I- [90] in accordance with FM P7825 capable of withstanding an uplift pressure of [90] psf.

1.04

DELIVERY, STORAGE, AND HANDLING

A. Delivery: Deliver materials in manufacturers' original unopened containers and rolls with labels intact and legible. Mark and remove wet or damaged materials from the site. Where materials are covered by a referenced specification, the container shall bear the specification number, type, and class, as applicable. [Labels or bill of lading for roofing asphalt shall indicate asphalt type, FP, FBT, and EVT, that is, the temperature at which the viscosity is either 125 centistokes when tested in accordance with ASTM D 2170 or 75 centipoise when tested in accordance with ASTM D 4402.] Deliver materials in sufficient quantity to allow work to proceed without interruption.

B. Storage: Protect materials against moisture absorption. Store roll materials on end on clean raised platforms or pallets one level high in dry locations with adequate ventilation, such as an enclosed building or closed trailer. Do not store roll materials in buildings under construction until concrete, mortar, and plaster work is finished and dry. Maintain roll materials at temperatures above 50 degrees F for 24 hours immediately before application. Do not store materials outdoors unless approved by the Contracting Officer. Completely cover felts stored outdoors, on and off roof, with waterproof canvas protective covering. Do not use polyethylene sheet as a covering. Tie covering securely to pallets to make completely weatherproof and yet provide sufficient ventilation to prevent condensation. Do not store more materials on roof than can be installed the same day and remove unused materials at end of each days work. Distribute materials temporarily stored on roof to stay within live load limits of the roof construction.

C. Handling: Select and operate material handling equipment so as not to damage applied roofing. Prevent damage to edges and ends of roll materials.

1.05 ENVIRONMENTAL REQUIREMENTS: Do not install roofing system when air temperature is below 40 degrees f, during any form of precipitation, including fog, or when there is ice, frost, moisture, or any other visible dampness on the roof deck. Provide manufacturer's printed directions for installation during cold weather conditions.

1.06 SEQUENCING: coordinate the work with other trades to ensure that components which are to be secured to or stripped into the roofing system are available and that flashing and counter flashing are installed as the work progresses.

1.07 WARRANTY: furnish the modified bitumen sheet roofing system manufacturer's "no-dollar-limit" warranty for the roofing system, including insulation, flashing, and accessories. The warranty shall run directly to the government. In no event shall the warranty period be less than 20 years from the date of the government's acceptance of the work, notwithstanding roofing applicator's or manufacturer's unpaid invoices for installation, supplies, or service. The warranty shall state that:

A. When within the warranty period the roofing system becomes nonwatertight, splits, tears, blisters, or separates at the seams or shows any other evidence of excessive weathering, because of defective materials or workmanship, the repair or replacement of defective materials and correction of defective workmanship shall be the responsibility of the manufacturer;

B. When the manufacturer or the manufacturer's approved applicator fail to perform repairs within 72 hours of notification, emergency repairs performed by others will not void the warranty; and

C. Damage to the roofing system caused by sustained winds having a velocity of [75] mph or less is covered by the warranty.

part 2 - PRODUCTS

2.01

DESCRIPTION OF ROOFING SYSTEM

A. [[SBS] [APP] Modified Bitumen Sheet on Nailable Substrate

[Substrate: [Wood] [Plywood]

Components:

Quantity:

Base Sheet (GB)

1 ply

Mechanical Fasteners

See subpara. "a" below

Type III or IV Asphalt

25 lbs/100 sq. ft.

SBS Modified Bitumen Base Sheet (MB) 1 ply

Type III or IV Asphalt

25 lbs/100 sq. ft.

SBS Modified Bitumen Cap Sheet (RSS) 1 ply]

a. Quantity and spacing of fasteners shall be in conformance with modified bitumen sheet manufacturer's requirements.]

[Substrate: [Wood] [Plywood]

[Insulation

See subpara. "a" below

Base Sheet (GB)

1 ply

Mechanical Fasteners

See subpara. "b" below

APP Modified Bitumen Sheet (RSA)

Top Surfacing

a. Roof insulation shall conform to the requirements specified in Section 07220, "Roof and Deck Insulation."

b. Quantity and spacing of fasteners shall be in conformance with modified bitumen sheet manufacturer's requirements.

c. Protective coating shall be in conformance with modified bitumen sheet manufacturer's requirements.

[Substrate: Metal Deck

Insulation

1 per 2 sq. ft.

Type III or IV Asphalt

25 lbs/100 sq. ft.

SBS Modified Bitumen Base Sheet (MB)

SBS Modified Bitumen Cap Sheet (RSS) 1 ply

[Substrate: Metal Deck

Insulation

1 per 2 sq. ft.

See subpara. "c" below

a. Roof insulation shall conform to the requirements specified in Section 07220, "Roof and Deck Insulation."

b. Quantity of asphalt shall be in accordance with modified bitumen sheet manufacturer's requirements.]

c. Protective coating shall be in conformance with modified bitumen sheet manufacturer's requirements.]

B. [APP] [SBS] Modified Bitumen Sheet on Non-Nailable Substrate

[Substrate: Poured-in-Place Concrete

Asphalt Primer

3/4 gal/100 sq.ft.

Spot-mop

Ventilating Base Sheet (VB)

a. Protective coating shall be in conformance with modified bitumen sheet manufacturer's requirements.]

[Substrate: Poured-in-Place Concrete

Asphalt Primer

3/4 gal/100 sq. ft.

SBS Modified Base Sheet (MB)

SBS Modified Bitumen Cap Sheet (RSS) 1 ply]

2.02

MATERIALS

A. Asphalt: ASTM D 312, Type III or IV.]

B. Modified Bitumen Sheet, Felts:

Designation Use Felt Impregnant Coating Specification

GB Base Sheet Glass Asphalt Asphalt

ASTM D 4601,

Type II, without perforations

MB SBS Modified Fiber- SBS Modified SBS Modified See subpara.

Base Sheet glass Bitumen Bitumen "a" below and/or

Poly-ester

VB Ventilating Glass Modified Modified

ASTM D 4897,

Base Sheet

Bitumen Type II

RSA APP

Fiber-

APP

APP

Modified

"b" below

Sheet

Roofing Poly-ester

RSS SBS

Fiber-

SBS

SBS

Bitumen Cap

Modified Bitumen/ "c" below

Sheet Roofing

Granules

Polyester

a. Modified bitumen base sheet shall be a prefabricated styrene butadiene styrene (SBS) modified bitumen sheet, 75 mil thick minimum, weighing 50 pounds per 100 sq. ft.

minimum, with a layer of fiberglass and/or polyester sheet reinforcement, and fire rated.

b.

Modified bitumen sheet shall be a prefabricated atactic polypropylene (APP) modified bitumen sheet, 150 mil thick minimum, weighing 88 pounds per 100 sq. ft. minimum, monolithic polymer modified matrix containing bitumen, polypropylene, and other resins, with a layer of fiberglass and/or polyester sheet reinforcement. The membrane shall contain a built-in adhesive on the underside so that the membrane and lapped joints are capable of being tack-applied.

c. Modified bitumen shall be a prefabricated styrene butadiene styrene (SBS) modified bitumen sheet, 112.5 mil thick minimum, weighing 100 pounds per 100 sq. ft. minimum, with a layer of fiberglass and/or polyester sheet reinforcement, and fire rated.

C. Top Surfacing: Protect modified bitumen roofing system from direct exposure to the weather with one of the following surfacings as recommended by the modified bitumen roofing system manufacturer.

1. Mineral Roofing Granules: Factory applied, requiring no further coating.

2. Protective Coating: The membrane manufacturer's standard protective coating applied in accordance with the roofing membrane manufacturer's printed application instructions.

3. Gravel: Aggregate surfacing material conforming to ASTM D 1863, sized and of the quantity recommended by the modified bitumen roofing system manufacturer.

D. Primer: ASTM D 41.

E. Asphalt Roof Cement: ASTM D 4586, Type II for vertical surfaces, Type I for horizontal surfaces.

F. Fasteners: Provide noncorrosive fasteners as recommended by the modified bitumen sheet manufacturer's printed instructions and meeting the requirements of FM A/S4470. For felts, provide fasteners driven through metal discs, or one piece composite fasteners with heads not less than one inch in diameter or one inch square with rounded or 45 degree tapered corners.

1. [Masonry] [or] [Concrete] Walls and Vertical Surfaces: Provide hardened steel nails with flat heads, diamond shaped points, and mechanically deformed shanks not less than one inch long for securing felts, modified bitumen sheets, and metal Items to [masonry] [or] [concrete] walls and vertical surfaces. Use power-driven fasteners only when approved in writing.

G. Metal Discs (Tin Caps): Flat noncorrosive fasteners as recommended by the modified bitumen sheet manufacturer's printed instructions and meeting the requirements of FM A/S4470; not less than inches in diameter, when using screw type fasteners. Discs shall be formed to prevent dishing or cupping.

H. Roof Insulation Below Modified Bitumen Membrane System: Insulation shall be compatible with the membrane as recommended in modified bitumen manufacturer's printed instructions [and as specified in Section 07220, "Roof and Deck Insulation".

PART 3 - EXECUTION

3.01 vERIFICATION OF CONDITIONS: Ensure that the following conditions exist prior to application of the roofing materials:

A. [Drains,] [curbs,] [cants,] [control joints,] [expansion joints,] [perimeter walls,] [roof penetrating components,] [and] [equipment supports] are in place.

B. Surfaces are rigid, dry, smooth, and free from cracks, holes, and sharp changes in elevation. Joints in the substrate are sealed to prevent dripping of bitumen into building or down exterior walls.

C. The plane of the substrate does not vary more than 1/4 inch within an area 10 by 10 feet when checked with a 10 foot straight edge placed anywhere on the substrate.

D. Substrate is sloped as indicated to provide positive drainage.

E. Walls and vertical surfaces are constructed to receive counter flashing, and will permit nailing of the base flashing materials.

F. Treated wood nailers are fastened in place at eaves, gable ends, openings, and intersections with vertical surfaces for securing of felts, edging strips, gravel stops, and roof fixtures.

G. Cants are securely fastened in place in the angles formed by walls and other vertical surfaces. The angle of the cant is 45 degrees and the height of the vertical leg is not less than nominal 4 inches. Cants are constructed of [treated wood] [wood fiberboard roof insulation].

H. Venting is provided in accordance with the following:

1. [Edge Venting: Perimeter nailers are kerfed across the width of the nailers to permit escape of gaseous pressure at roof edges.]

2. [Underside Venting: Vent openings are provided in steel form decking for cast-in-place concrete substrate.]

3. [Moisture release vents: Holes equal to the outside diameter of vents are provided through the insulation where vents are required.]

I. [Insulation boards are installed smoothly and evenly, and are not broken, cracked, or curled. Insulation is being roofed over on the same day the insulation is installed.]

J. [Cast-in-place substrates have been allowed to cure and the surface dryness requirements specified under paragraph entitled "Field Quality Control" have been met.]

K. [Joints between precast concrete deck units are grouted and leveled.]

3.02

PREPARATION

A. Protection of Property

1. Protective Coverings: Install protective coverings at paving and building walls adjacent to hoist [and kettles] prior to starting the work. Lap protective coverings not less than six inches, secure against wind, and vent to prevent collection of moisture on covered surfaces. Keep protective coverings in place for the duration of the roofing work.

2. Flame-Heated Equipment: Do not place flame-heated equipment on roof. Provide and maintain a fire extinguisher adjacent to flame-heated equipment and on the roof.

3. Open Flame Application Equipment: Torches and other open flame equipment shall be specifically designated for use in application of modified bitumen and approved by the modified bitumen sheet manufacturer. Open flame equipment shall not be ignited (burning) when left unattended. Provide and maintain a fire extinguisher adjacent to open flame equipment on the roof.] [Apply a base sheet, in accordance with modified bitumen sheet manufacturer's recommendations, to combustible substrates prior to torch-application of modified bitumen membrane.] [Specific requirements for fire watches and burn permits exist. These requirements will be outlined at the preroofing conference.]

4. Electric-Heated Equipment: Provide adequate electrical service as required by manufacturer of electrical equipment to ensure against damage to equipment and property and to ensure proper application of roofing materials.

B. Priming of Surfaces: Prime surfaces at the rate of 0.75 gallon per 100 sq. ft. or as recommended by modified bitumen sheet manufacturer's printed instructions and allow to dry.

1. Priming of Concrete and Masonry Surfaces: After surface dryness requirements have been met, coat concrete and masonry surfaces which are to receive base sheet and roofing materials uniformly with asphalt primer. Allow primer to dry prior to application of base sheet, roofing, and flashing.

2. Priming of Metal Surfaces: Prime flanges of metal edging strips, prior to stripping into roofing system in accordance with modified bitumen manufacturer's printed instructions and allow to dry.

C. Heating of Asphalt: Break up solid asphalt on a surface free of dirt and debris. Heat asphalt in kettle designed to prevent contact of flame with surfaces in contact with the asphalt. Kettles shall have visible thermometer and thermostatic controls set to the temperature limits specified herein. Keep controls in working order and calibrated. Use immersion thermometer, accurate within a tolerance of plus or minus 2 degrees F, to check temperatures of the asphalt frequently. When temperatures exceed maximums specified, remove asphalt from the site. Do no permit cutting back, adulterating, or fluxing of asphalt.

3.03 APPLICATION: apply roofing materials as specified herein unless specified or recommended otherwise by manufacturer's printed application instructions. Keep roofing materials dry before and during application. Do not permit phased construction. Complete application of roofing in a continuous operation. begin and apply only as much roofing in one day as can be completed that same day. Maintain specified temperatures for asphalt. Modified bitumen base sheet shall not remain exposed prior to application of the modified bitumen cap sheet unless approved by the contracting officer and supported by the manufacturer's standard written application instructions. [Provide temporary roofing and flashing as specified herein prior to application of permanent roofing system.]

A. Temporary Roofing and Flashing: Provide temporary roofing and flashing where considerable work by other trades, such as installing [cooling towers,] [antennas,] [pipes,] [ducts,] is to be performed on the roof or where construction scheduling or weather conditions require protection of the building's interior before permanent roofing system can be installed. Do not install temporary roofing over permanently installed insulation. Provide rigid pads for traffic over temporary roofing.

1. Temporary Roofing Membrane: Install 2 plies of ply felt in accordance with the application procedures specified [; except spot mop the first ply on cast-in-place concrete decks by brooming felts into 2 inch diameter spots of asphalt spaced 18 inches o.c].

2. Temporary Flashing: Install temporary flashing consisting of one ply of ply felt. Place ply felt in a trowel coat of asphalt roof cement and cover with a trowel coat of asphalt roof cement.

3. Removal: Completely remove temporary roofing and flashing before continuing with application of the permanent roofing system.]

B. Bitumen Stops: Provide bitumen stops at roof edges, openings, and vertical projections before hot mopped application of the roofing membrane (base sheet and modified bitumen). Do not provide sheet metal bitumen stops. Form bitumen stops of two 18 inch wide strips of organic felt conforming to ASTM D 226. ply felts. Attach nine inches of the width to the roof surface and extend 9 inches beyond the edge. Apply first strip in a 9 inch wide layer of asphalt roof cement and, where nailers are provided, nail on 6 inch spacing 1/2 inch from the edge. Apply second strip in a 9 inch wide mopping of asphalt. Protect the free portion of each strip from damage throughout the roofing period. After the roofing plies are in place, fold the free portion of each strip over the roofing membrane and embed in a continuous coating of asphalt roof cement and secure with fasteners 3 inches o.c.

C. Ventilating Base Sheets: Apply ventilating base sheets in accordance with manufacturer's printed application instructions.

D. Base Sheet: Apply base sheets in shingle fashion [in hot mopping of asphalt]. [On nailable substrates, mechanically fasten base sheet in conformance with FM requirements and membrane manufacturer's printed instructions. Where applicable, base sheet may be mechanically fastened in conjunction with insulation to the substrate, in accordance with membrane manufacturers printed instructions.] Apply sheets in a continuous operation. Apply sheets with side laps at a minimum of 2 inches unless greater side lap is recommended by the manufacturer's standard written application instructions. Provide end laps of not less than 6 inches and staggered a minimum of 36 inches. Apply sheets [at right angles to the roof slope so that the direction of water flow is over and not against the laps] [parallel to the roof slope so that prevailing winds are over and not against the laps] [so that plies of sheets extend from eave line on one side of the barrel-type roof and 18 inches over the center line of the crown of the roof. Apply sheets on the other side in the same manner, resulting in twice the normal amount of roofing sheets and asphalt at the crown]. Extend sheets approximately 2 inches above the top of cant strips at vertical surfaces and to the top of cant strips elsewhere. Trim felt to a neat fit around vent pipes, roof drains, and other projections through the roof. Application shall be free of ridges, wrinkles, and buckles.

E. Hot-Mopping of Base Sheets: Provide hot asphalt for embedding of base sheets [, including modified bitumen base sheet,] to the [insulation] [substrate]. Apply base sheets immediately following application of hot asphalt. Do not work ahead with asphalt. Asphalt shall be completely fluid, with mop temperatures within the specified EVT range, at the instant base sheets come into contact with asphalt. Application of bitumen between plies shall be such as to provide full, continuous, uniform coverage and complete penetration of asphalt into the sheet above and below. Embed sheets in asphalt. As sheets are being rolled into hot asphalt, immediately and thoroughly squeegee, roll, or broom down to eliminate trapped air and to provide tight, smooth laminations without wrinkles, buckles, kinks, and fish mouths. Completed system shall be free of air pockets and blisters.

1. Temperature Limitations for Asphalt: Heat and apply asphalt at the temperatures specified below unless specified otherwise by manufacturer's printed application instructions. Use thermometer to check temperature during heating and application. Have kettle attended constantly during heating process to ensure specified temperatures are maintained. Do not heat asphalt above its FBT. Do not heat asphalt between 500 and 525 degrees F for longer than four consecutive hours. Do not heat asphalt to the flash point (FP). Apply asphalt and embed base sheets when temperature of asphalt is within plus or minus 25 degrees F of the equiviscous temperature (EVT). Before heating and application of asphalt refer to the asphalt manufacturer's label or bill of lading for FP, FBT, and EVT of the asphalt used.

F. Modified Bitumen Sheets: Sheets shall be watertight and visually free of pinholes, particles of foreign matter, undispersed raw material, or other manufacturing defects that might affect serviceability. Edges of seams shall be straight and flat so that they may be seamed to one another without forming fish mouths or wrinkles.

1. APP Modified Bitumen Sheets: Torch-on or electric heat-apply fully adhered sheets. Unroll sheets, set in place with 3 inch side laps and 6 inch end laps. Apply heat to underside of roll and 3 inch side lap of preceding roll and fully adhere membrane to the substrate by unrolling the heated portion of the roll onto the substrate. Ensure a minimum flow of modified bitumen of at least 3/8 inch, not to exceed one inch, on side and end laps as the membrane is rolled forward and adhered to the substrate. Care shall be taken so as not to overheat the top surface of the roll. After membrane has been adhered to substrate, check laps with a hot trowel to ensure laps are fully adhered. At areas where full adhesion of the laps are not obtained, reheat and trowel into place so that adhesion of the entire lap is accomplished.

2. SBS Modified Bitumen Sheets: Solid mop top surface of base sheet with hot asphalt at the rate of 25 pounds per 100 sq. ft. and embed one layer of roofing membrane into hot asphalt. Roll modified bitumen roofing membrane into place with a flow of hot asphalt out of side and end laps. Side laps shall be 4 inches and end laps shall be 6 inches. Stagger end laps a minimum of 36 inches. Back mop end laps. Apply roofing in a continuous application. Start installation at the low point of the roof and progress to the high point. Provide tight, smooth laminations without wrinkles, ridges, buckles, kinks, and fishmouths. Completed system shall be free of air pockets, blisters, ridges, fishmouths, and open laps.

G. Flashings: Apply modified bitumen sheet flashing in the angles formed where the roof deck abuts walls, curbs, ventilators, pipes, and other vertical surfaces, in accordance with membrane manufacturer's printed application instructions and where necessary to make the work watertight. Metal flashing collars and cap flashings are specified under Section 07600, "Flashing and Sheet Metal." Do not set metal flashing in hot asphalt.

1. Flashing at Roof Drain: Roof drains are specified under Section 15400, "Plumbing Systems." Flashing for roof drains, are specified under Section 07600, "Flashing and Sheet Metal." Extend [base sheet and] modified bitumen sheets to edge of drain bowl opening at the roof drain deck flange in accordance with membrane manufacturer's printed application instructions. Securely clamp base sheet, modified bitumen sheets, and metal roof drain flashing and strip flashing in the flashing clamping ring. Secure clamps so that sheets and metal flashing are free from wrinkles and folds.

H. Roof Walkways: Install precast concrete paver block or asphalt plank roof walkways, where indicated, for traffic areas and for access to mechanical equipment, in accordance with the modified bitumen sheet roofing manufacturer's printed instructions. Provide an additional cap sheet under precast concrete paver blocks to protect the roofing.

I. Moisture Release Vents: Set vents in a uniform pattern and at a minimum rate of one for each 1000 square feet of roof area. Install in strict accordance with manufacturer's instructions.]

J. Fire Watch: Provide fire watch during torch application and continue for one hour after completion of torch application. Provide at least two 2 1/2 gallon containers of water and two 15 pound CO2 extinguishers for use during the fire watch.

K. Clean Up: Remove debris, scraps, containers and other rubbish and trash resulting from installation of the roofing system from job site each day.

L. Protection of Applied Roofing Against Moisture Absorption: At the end of the day's work and when precipitation is imminent, protect applied modified bitumen roofing system as follows.

1. Water Cutoffs: Straighten insulation line using loose-laid cut insulation sheets and seal the terminated edge of modified bitumen roofing system with two full width strips of roofing felt set in and coated with asphalt roof cement. One-half width of the strips shall extend up and over the finished roofing and the other half-width extended out onto the bare deck unless recommended otherwise in membrane manufacturer's printed application instructions. [Seal off flutes in metal decking along the cutoff edge.] Pull membrane free or cut to expose the insulation when resuming work, and remove the insulation sheets used for fill-in.

2. Temporary Flashing for Permanent Roofing: Provide temporary flashing at drains, curbs, walls and other penetrations and terminations of roofing sheets until permanent flashings can be applied. Temporary flashings shall consist of one ply of ply felt applied in a trowel coat of asphalt roof cement applied to a primed surface, and finished with a surface coat of asphalt roof cement. Remove temporary flashing before applying permanent flashing.

3. Temporary Walkways, Runways, and Platforms: Do not permit storing, walking, wheeling, and trucking directly on applied roofing materials. Provide temporary walkways, runways, and platforms of smooth clean boards or planks as necessary to avoid damage to applied roofing materials, and to distribute weight to conform to indicated live load limits of roof construction. Use rubber-tired equipment for roofing work.

3.04 FIELD QUALITY CONTROL: Perform field tests in the presence of the contracting officer. Notify the contracting officer one day before performing tests.

A. Test for Surface Dryness: Before application of base sheets and starting work on the area to be roofed, perform test for surface dryness in accordance with the following:

1. Foaming: When poured on the surface to which felts are to be applied, one pint of asphalt when heated in the range of 350 to 400 degrees F, shall not foam upon contact.

b. Strippability: After asphalt used in the foaming test application has cooled to ambient temperatures, test coating for adherence. Should a portion of the sample be readily stripped clean from the surface, do not consider the surface to be dry and do not start application. Should rain occur during application, stop work and do not resume until surface has been tested by the method above and found dry.

B. Roof Drain Test: After completing roofing but prior to Government acceptance, perform the following test for watertightness. Plug [primary] roof drains and fill with water to edge of drain sump for 24 hours. [Do not plug secondary overflow drains.] To ensure some drainage from roof, do not test all drains at same time. Measure water at beginning and end of the 24-hour period. When precipitation occurs during test period, repeat test. When water level falls, remove water, thoroughly dry, and inspect installation; repair or replace roofing at drain. Repeat test until there is no water leakage.

C. Instructions to Government Personnel: Furnish written and verbal instructions on proper maintenance procedures to designated Government personnel. Furnish instructions by a competent representative of the modified bitumen membrane manufacturer and include a minimum of 4 hours on maintenance and emergency repair of the membrane. Include a demonstration of membrane repair, and give sources of required special tools. Furnish information on safety requirements during maintenance and emergency repair operations.

-- End of Section--

SECTION 07550 PAGE 1