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Under One Roof

Canadian Roofing Reference Manual

7.2.8 Installation Precautions

Job Site Considerations

  • Asphalt, coal tar based, oil based and plastic roof cements, and re-saturated roof products are not to be used in direct contact with rubber-based components of the thermoset system.
  • Protect all components of the thermoset system from discharges, such as petroleum products, greases, oils (mineral and vegetable), and animal fats.
  • Protect the thermoset system from direct contact with steam or heat sources when the in-service temperature is in excess of 82°C (180ºF).
  • Consider the effect of loads on the structure/decking due to the staging of materials as a part of system installation.
  • During installation, appropriate measures shall be taken to assure that fumes from adhesive solvents are not drawn into the building through rooftop air intakes.
  • Protect the roof system during installation from damage by other trades.

Special Considerations for Re-roofing & Recover Applications

  • The effect of moisture present in the existing roof system on the performance of the new system may be significant depending upon the components selected. Therefore, a moisture survey should be conducted to determine the moisture content of the existing roof system components. Any wet or unsound portions of the existing roof must be removed and replaced with new materials prior to the installation of the thermoset system.
  • Confirm compatibility of new components with existing roof type (i.e. some manufacturers recommend against placing certain types of insulation in contact with coal tar built-up roofs).
  • If nailers are reused, confirm the structural integrity of the nailer and nailer attachment. Existing blocking surfaces that will be in contact with the thermoset membrane and that are contaminated with incompatible materials will have to be covered or the blocking removed and replaced with new materials.
  • Substrates must be clean, dry, smooth, free of sharp edges, fins, loose or foreign materials, oil, grease and other materials which may damage the membrane.
  • All rough surfaces which could damage the membrane shall be prepared as required by membrane manufacturer to provide a smooth substrate.
  • All surface voids greater than 6 mm (1/4 in) wide shall be properly filled with an acceptable fill material.

Precautions – Adhesives, Sealants and Cleaners

  • These products are highly flammable. Keep away from fire and open flames. Do not smoke when using.
  • Avoid prolonged contact with skin. Gloves should be worn.
  • Use solvent-borne materials only in well ventilated areas.
  • Keep adhesives, sealants and cleaners away from fire and ignition sources during storage and installation.
  • Use of heat guns during cold weather will improve workability of flashing, but a wide nozzle should be used and care should be taken not to localize heat as a hole in the flashing can result.
  • These products may contain lead or other harmful components. Always wash hands after using. Wash hands before eating or drinking.
  • Store these products in original unopened cartons at temperatures between 16 to 27°C (60 to 80°F) until ready for use.
  • During hot weather, do not expose to sunlight/elevated temperatures until use.
  • Rotate your stock to insure stored material will not go beyond the shelf life printed by the manufacturer. Shelf life will be shortened if exposed to elevated temperatures.

Splices & Seams

  • Position the membrane to overlap the distance specified along the entire length of the splice.
  • Allow the membrane to relax a minimum of 30 minutes prior to attachment.
  • Fold the top sheet back to allow for cleaning of both surfaces that are to be spliced.
  • Clean the dry mating surfaces using clean cotton cloths with the specified splice cleaner. Allow to dry. Additional cleaning may be required to assure that the membrane is completely cleaned.
  • Caution: more attention should be given to cleaning the areas at factory seams.
  • Cotton cloths must be discarded as they become dirty and replaced with clean ones to assure proper cleaning. Proper cleaning has been achieved when the membrane surface is dark grey in colour and no streaking is evident.
  • Apply the splice adhesive with a brush or a roller in a thick, even smooth coat with long painting type strokes such that brush marks bleed out, yielding a smooth, glossy adhesive surface. Both mating surfaces shall have splice adhesive applied at about the same time so as to allow approximately the same flash-off time. Use rollers that are specified for this type of product (paint rollers may not be appropriate). Do not use spray equipment, or mechanical equipment for the application of splice adhesive or apply splice adhesive with a brush attached to a long handle.
  • Allow the solvents in the splice adhesive to flash off. Touch the adhesive surface in the middle of the area to be spliced with a clean, dry finger to be certain that the adhesive does not stick or string. As you are touching the adhesive, pushing straight down to check for stringing, also push forward on the adhesive at an angle to ensure that the adhesive is ready throughout its thickness. If either motion exposes wet or stringy adhesive when the finger is lifted, then it is not ready for mating and the seam should not be closed. Flash off time will vary depending on ambient air conditions.
  • Roll the top sheet toward the lap area until the adhesive-coated area nearly touches the adhesive on the bottom sheet along the entire length of the lap. Allow the top sheet to fall freely onto the bottom sheet so as not to stretch or wrinkle the membrane. Apply pressure along the entire length of the splice by hand to completely mate the two surfaces. Roll the entire lap splice using a hand roller with positive pressure towards the outside edge of the lap, then along the entire length of the lap, being careful not to damage the membrane.
  • Review Safety Data Sheet prior to use.
  • After a can has been opened once and closed, use remainder of adhesive within one week.
  • Cover cans when not in use. When applying adhesive, work out of small pails with a cover to avoid skimming over of adhesive.
  • When exposed to lower temperatures, restore to room temperature prior to use.
  • Do not attempt to thin or otherwise adulterate these materials.

Recommended guidelines for applications of roofing adhesives on occupied buildings

  • When at all possible, the air intake system should be completely shut down if the intakes are on the roof. Air intakes should also be blocked to prevent fumes from seeping into the air system and collecting in low areas.
  • In order to minimize the concern or any possible discomfort of the building’s occupants, consideration should be given to applying the roof when the building is empty or occupancy is at a minimum.
  • Resumption of air circulation should occur only after the roof has been closed and the fumes have dissipated. If possible, the building should be well aired before occupants return. This will reduce any lingering odours and any possible cause for concern on the part of the occupants.
  • If static (passive) air vents are employed on the roof, these should be sealed as well as possible to prevent fumes from entering the building. They should be unsealed only after the roof has been closed and the solvent fumes have dissipated.
  • If it is not practical to shut down or seal off the ventilation system, attempts should be made to work as fast as possible around air vents with a minimum amount of adhesive coated roof exposed. If multiple vents are used, it may be possible to seal off only the vent or vents nearest the portion of roof where adhesive is being applied.