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Under One Roof

Canadian Roofing Reference Manual

7.1.5 General Installation Precautions

Thermoplastic membranes require care and skill to install. The following is a list of precautions that you should be aware of that will help avoid problems during and after the membrane’s installation.

  • Handle the rolls of membrane carefully. By throwing them around or dropping them, you could create a puncture in the membrane which will pierce many layers of material.
  • Stack single ply rolls over a sturdy supporting beam on the structure being roofed. The rolls are heavy and too many piled in the wrong spot on a roof could cause a collapse.
  • Try to arrange the roof top storage of rolls to the areas you will be working on. This will result in less movement of the material during installation, reducing the possibility of membrane damage.
  • Keep rolls covered to prevent water absorption. If the membrane absorbs any water, it will be difficult to weld.
  • Check rolls as they are being rolled out to make sure a puncture hasn’t occurred in the membrane by the roll dropping on a stone or some object falling on the roll.
  • When using large prefabricated sheets, inspect and document the condition and location of the factory welds. This eliminates any argument if a factory weld fails after installation. You should not be held responsible for the integrity of factory welds.
  • Plan the job so that you are always working away from the new roof area and not crossing over it to get to unfinished areas.
  • When installing a membrane in retrofit jobs, use one set of boots and tools for the tear off procedure and different boots and tools for the application procedure. This will prevent any contaminants from the old roof from coming in contact with the new membrane.
  • Upon returning from a break before stepping on the membrane, quickly wipe the bottom of each boot with your hand to assure that metal chips or small nails are not embedded in the sole. The few seconds it takes to do this can save many hours of searching for penetrations and replacing a new membrane that has been damaged.
  • When using adhesive on adhered systems, follow the manufacturer’s instructions regarding adhesive application and setting prior to membrane placement.
  • Install membrane perimeter fixation at all membrane edges in accordance with the membrane system manufacturer’s current requirements.
  • Do not spill adhesives or solvents on the membranes. This may alter the physical structure of the membrane and cause a failure at a later date.
  • Do not weld rolls when their edges are wet or dirty. This can trap moisture in the membrane, contaminate the weld, and lead to premature failure of the weld.
  • Do not use contaminated, dirty or aged material. Old material oxidizes and seams will not weld properly. Make sure all debris is washed away from the repair area and the membrane is properly cleaned and prepared before attempting a repair.
  • Do not use sharp gravel as ballast directly on the membrane. If rounded stone aggregate (stones with more than a 60º edge) is not available, consider using a different attachment method or put down an approved protection mat over the membrane prior to installing the ballast.
  • Do not lay out large areas of material that are unsecured. In some instances, bags filled with gravel are used to temporarily weigh down the membrane edge to keep the wind from lifting the membrane during construction. When the job is finished, the bags can simply be emptied out and the ballast left on the roof.