Developed in the 1960s in Europe specifically for flat or low-slope roofs, modified bitumen is designed to withstand temperature fluctuations and foot traffic without tearing, lifting or cracking and can be installed over the top of an old roof if certain conditions are met, eliminating the tear-off step. The step-by-step installation process is as follows:
It must be noted that the following torch-down method of installation for modified bitumen roofing should only be performed by a qualified roofer, as the process can be dangerous.
- The roof is cleared of any debris or dirt build-up.
- Heavy roofing felt is nailed to the decking or insulation in preparation for the membrane.
- The drip edge and flashings are installed and primed with adhesive.
- Sheets of roofing membrane are rolled out and cut, with a few inches of overhang allowed to remain.
- The roofing membrane is adjusted to ensure the proper overhang as well as smoothing the membrane to a perfectly flat surface.
- The roofing membrane is then re-rolled tightly about halfway.
- Seams are sealed using a cold-applied adhesive (aka solvent-welding) and a squeegee is used to properly seal the adhered seams together.
- This process is repeated, overlapping the edges of the sheets.
- The new seam is pressed tight using a foot or gloved hand to ensure a tight seal.
- The process is repeated until the entire roof is covered and sealed.
- The roof must remain undisturbed for the duration of the setting process, as foot traffic could displace the adhesive and compromise the waterproof seals.
The cold-adhesive application method is outlined here, but modified bitumen can also be installed by using a self-adhering sheet, making the installation even easier for the roofers and saving you labor costs. Cold-process adhesive methods do not give off chemical fumes during or after application. In some areas at risk of experiencing high winds, mechanical fasteners are used to create the strongest wind resistance.
AKVM Roofing is dedicated to providing you with all the information you need to determine which type of roofing is best suited for your commercial building, and we guarantee our materials and workmanship so that you feel at ease with your business’ new roof. Questions about modified bitumen roofing?
Contact us today