APP Modified Bitumen Torch Grade Membrane for Smooth Roof Installation

app modified bitumen collage

Copyright: Auremar

APP modified bitumen membranes came to the United States from Europe in the late 1970s. This technology and its installation method have been around in the construction industry for over 30 years. When Ridge Top Exteriors of Madison installs this type of roofing system there are basic safety measures taken before we get started.

APP modified bitumen torch grade membranes are not installed without careful review and implementation of all applicable safety and fire watch requirements.

Our crews are fully familiar of Propane Gas Equipment Storage and Handling guideline and Workers’ Safety Precautions learned in their extensive training is followed throughout the process.

As with all installation of a roofing system, safety is a key element. Ridge Top Exteriors will remove all potentially flammable articles from the work area for fire prevention.

Step 1: Ridge Top Exteriors Preparation

The surface over which the membrane is to be installed will be cleaned, smoothed and dried, and prepared in accordance with the USP 160 specification manual.

Suitable torching substrates are:
structural concrete
self-adhered/mechanically fastened/asphalt-adhered base sheets and ply sheets
Gypsum cover boards.

Substrates not suitable for torching are:
Insulation boards such as polisocyanurate, perlite and wood fibre.
Fresh asphalt glazes or flood coats
Solvent-based cold adhesives or mastics

Other flammable substrates such as wood, plywood and oriented strand boards APP membranes cannot be applied during adverse weather or without precautionary measures and temperatures below 45 degrees Fahrenheit. There is also a reference on the cold weather precautions section of the USP 160 specifications manual.

For slopes less than 3 inches per foot, Ridge Top Exteriors installs cap sheets perpendicular to the slope. For slopes 3 inches and over, APP torch grade membranes will run vertically or parallel to the roof slope. All laps are parallel or perpendicular to the slope above the roof so that water is never running against the lap edge.

Step 2: Using the Propane Torch

flat roof app torch grade membrane

Copyright: Dmitry Kalinovsky


Our flat roof installation crew has read and understands all information on the torch equipment operation manual for safe torch ignition. They will only proceed after verifying that the torch is properly connected and that the hoses are in good working condition. They check all fittings and equipment for leakage by using soapy water to detect gas leaks.

Step 3: Roll Alignment

After the crew members remove the tape from the roll, the cold APP membrane will be unrolled approximately 10 feet, aligned, and then rerolled to apply. When they come across a slope or uneven substrate, they will unroll the membrane completely and give it time to relax then work out any wrinkles that would cause misalignment or cause the membrane to curve downslope. Our guys work as a team with one person standing on one end of the roll while another person shifts the membrane at the other end from side to side to help the membrane lie flat. This is to ensure that the membrane is aligned properly without wrinkles.

Ridge Top Exteriors commercial roof installation crews are thoroughly familiar with the importance of all of the safety precautions when installing APP modified bitumen torch grade roof felt to prevent accidents or property damage. Our proper handling results in a hassle-free installation for a leak-free roof.