|
|
Johns Manville
Commerical Industrial Roofing Systems\Built-Up Roofing
Built-Up Roofing - Page 4
Commerical Industrial Roofing Systems\Built-Up Roofing
 |
Built-Up Roofing Specifications |
All safety guidelines applicable to standard asphalt should also be applied to the use of PermaMop modified asphalt. See Section 1.9 for more information.
6.8.4 Equiviscous Temperature
The Equiviscous Temperature of PermaMop asphalt is between
6.9.1 JM’s cold asphaltic cements and coatings are asbestos-free and are designed especially for use in asphaltic built-up roofing systems. They are used for priming various surfaces to improve bonding of membranes and flashings, as coatings for smooth-surface fiber glass roofs, for roof repair, for adhering flashings, or for sealing metal and other materials. JM also has cold cements which are designed to bond layers of fiber glass felts together to form a roof membrane without the use of hot asphalt.
6.9.2 Handling and Application
Cutback materials contain flammable solvents. Do not expose them to flame or high temperatures. Take all routine fire and safety
precautions. Do not heat these materials in closed containers or in open containers above
their flash point. Do not heat these materials under any circumstances with an open flame.
Do not apply any solvent-containing material in a confined space. Do not combine or dilute any of these materials.
6.9.3 Coverage and Selection of Roof Coatings and Surfacings6.9.3.1 The type and quantity of roof surfacing is dictated by the following: the specification selected, incline of the roof structure, and Underwriters Laboratories Classification required.
6.9.3.2 The following is a list of the surfacings available and typical application rates per square:
6.9.3.3 Refer to individual product information sheets for more detailed application instructions.
6.9.3.4 When final surfacing is not possible following application of the membrane, JM recommends, as good practice, that a glaze coat of hot asphalt (10-15 lbs. per square [0.49-0.73 kg/m2]) be mop or squeegee applied. To accommodate job conditions, the membrane may be left uncoated for a period of up to six months. Low spots and valleys should, however, be glazed to protect these areas of the roof. Following such delay, an appropriate repair must be made to all damaged areas and the entire roof surface cleaned and primed prior to final surfacing.
6.9.4 Topgard Type A or B
Store and apply Topgard Type A or B at temperatures above 40°F (4°C). Do not use if it
has frozen. Do not apply when rain or freezing temperatures are expected within 24 hours.
Apply Topgard Type A or B only to surfaces that are clean, dry, and free of dust and dirt. If the surface is not clean, dry, and free of dust or dirt, it must be primed with Concrete Primer prior to the applica-tion of the coating. Allow Topgard Type B to dry for at least 72 hours before installing any other coating over it. See the appropriate product data sheet for more complete application directions.
6.9.5 Fibrated Aluminum Roof
Coating
Asphalt surfacings, especially low softening point asphalts, continue to flex and flow
after they are applied, therefore, it is not recommended that Fibrated Aluminum Roof
Coating be applied over Type I and Type II asphalts. Higher softening point asphalts
should weather at least one summer prior to the application of Fibrated Aluminum Roof
Coating. If the Fibrated Aluminum Roof Coating must be applied right away, coat the roof
with Topgard Type B which has been allowed to dry for at least 72 hours, and then apply
the Fibrated Aluminum Roof Coating. Fibrated Aluminum Roof Coating must be thoroughly
mixed to a smooth consistency and uniform silver color prior to using.
No roof coating will resist standing water. Light-colored coatings such as Fibrated Aluminum Roof Coating are particularly susceptible to erosion and discoloration by ponded water. Valleys and low spots should be poured with asphalt and surfaced with gravel or a reflective aggregate such as marble chips.