7A.30.2 When the installation of the cap sheet is delayed for any reason, the following procedures should be followed:

A. Low spots and valleys must be glazed with Type III or IV asphalt at the rate of 10 - 15 pounds per square (0.49 - 0.73 kg/m2).

B. Prior to the application of the modified bitumen cap sheet, the surface of the membrane must be examined thoroughly for the presence of any moisture. If moisture is present, the application of the cap sheet is not to proceed until the moisture has been removed or evaporated and the surface is dry. If frothing or bubbling of the hot asphalt occurs, construction must stop immediately.

C. The surface of the membrane must be properly cleaned and primed if contaminated by dirt, dust, or debris. The primer must be completely dry prior to installation of the modified bitumen cap sheet.

D. Caution must also be exercised to avoid traffic over the newly installed modified bitumen cap sheet while the asphalt is still fluid. This can also contribute to the formation of voids.

7A.30.3 Under no circumstances shall the installation of the modified bitumen cap sheet be delayed more than 5 days after completion of the intermediate plies of the roofing system.

7A.30.4 Only multiple felt systems (two or three felts with modified cap sheet) or DynaBase, DynaPly and DynaLastic 180 S should be considered as the base felt(s) for the delay in application of the modified bitumen cap sheet. Single ply felt or base felt systems must receive the modified bitumen cap sheet on the same day.

7A.31 Cold Weather Application

7A.31.1 SBS modified bitumens require special application techniques when they are being installed in cold weather. The following precautions shall be taken when the ambient temperature drops below 50°F (10°C), and are mandatory below 40°F (4°C):

A. Modified bitumen products shall be kept warm, or warmed prior to installation. Store these materials indoors or in heated storage units or warming boxes. If these facilities are not available, placing the materials in direct sunlight may help. Make certain that modified bitumen rolls are stored on end only; do not store rolls on their side.

B. The mopping asphalt must have an EVT which will accommodate a minimum mop temperature of 400°F (204°C), however, 425°F (218°C) is preferred. This will improve the likelihood of fluxing the back coating on the sheet and the probability of an adequate bond.

C. When the rolling or scrolling techniques are used, the asphalt must be mopped in front of the roll no more than 4 feet (1.22 m), and the asphalt must not be allowed to cool before the sheet is laid into it. In cold temperatures, asphalt will "skin over" rapidly, which will prevent adhesion of the membrane.

D. When the conditions are extreme (below 40°F [4°C]) these precautions may prove to be inadequate to achieve a smooth installation. If prevailing conditions demand that the job continue, the rolls must be heated or completely unwound and allowed to warm for 12 to 15 minutes or until there are no apparent "waves" in the sheet. This shall be done with the darker side of the sheet up. The sheet may then be installed using rolled, scrolled or "mop and flop" techniques.

Note: The "mop and flop" technique has proven to be very effective  in cold weather situations, when short lengths of material are set in asphalt applied with a mechanical spreader. Polyester reinforced SBS modified bitumen may not be installed in this manner.

7A.32 Temporary Roof Coverings

7A.32.1 At times, an owner or general contractor may require the building to be closed in at a time when the weather is not conducive to good roof construction, or the roof area may have to be used as a work platform during construction. Historically, this situation has led to phase construction, which has resulted in premature roof failure.

7A.32.2 When the complete roof cannot be installed in one operation, the following procedures are recommended:

A. Nailable Decks:

1. Apply one layer of an approved JM base felt, lapping the felt 2" (51 mm), and nailing 9" (229 mm) o.c. along the lap and 12" (305 mm) o.c. through the center of the sheet. (Sheathing paper should first be installed on wood board decks.)

2. Mop one ply of an approved JM ply felt in ASTM D 312, Type III asphalt and apply a glaze coat of 10 - 15 lbs. per square (0.49 - 0.73 kg/m²) of Type III asphalt.

3. When the permanent roof is to be installed, inspect the roof and remove all damaged and blistered areas. Apply a layer of approved JM base felt nailed through the temporary roof and into the deck as the first layer of the roofing system. As an alternate, a layer of approved JM roof insulation may be mechanically fastened (with appropriate fasteners) through the temporary roof into the deck.

4. Proceed with installing the appropriate permanent roof specification.

B. Steel Decks:

1. Apply a minimum layer of Fesco Board or Fiber Glass Roof Insulation of adequate thickness to the steel deck using appropriate length UltraFast fasteners.

2. Install a ply of a JM ply or base felt and an additional ply of fiber glass felt, both in hot steep asphalt.

3. Finish with an 10 - 15 lbs. per square (0.49 - 0.73 kg/m²) glaze coat of hot steep asphalt.

4. When the permanent roof is to be applied, inspect the roof area. If the insulation has not been damaged and is dry, remove any blistered or damaged felt. Prime the temporary roof with JM Concrete Primer at the rate of 1 gal./sq. (0.4 liters/m²) and then solid mop a layer of insulation board to the temporary roof with hot asphalt. Then apply the permanent roof system. In some regions of the country a JM base felt may be machine spot-mopped directly to the sound temporary roof, followed by the roofing membrane. Consult a JM Technical Services Specialist for acceptability.

5. If the membrane and/or roof insulation has been excessively damaged, remove all unusable material and replace.