0

The roofing company I hired finished applying Polyfresko bitumen on my garage, and instead of welding the beginning and end of new layers at the edges, they overlapped one layer over another by about 6 inches, resulting in a “hump” of overlapping layers.

Is this normal? I thought the membrane would be completely flat. First example:

enter image description here

The overlap can be seen from the driveway:

enter image description here

Where one sheet ends, they overlapped the new sheet by about 6 inches instead of welding at the edge of the sheet:

enter image description here

2

No, it’s not normal for the edges to be loose.

Poly glass is a self sealing modified bitumen roofing product. See here:

http://www.polyglass.com/public/COM/products/POLYFRESKO_G_SA.pdf

As you can see in Item #6 of the installation instructions, the seams are to be lapped 6” and side lapped 4”.

I think it’s installed correctly.

If there are loose edges you could have leaks, blow-off, etc. AND your warranty is void.

| improve this answer | |
  • 1
    Op is not stating that the seams are loose. He is asking if the edge should overlap 6" verse edge against edge butt seams. I have no experience with the material under discussion, but I would guess that the overlaying makes a more water-tight seams. like installing shingles on a roof. – Programmer66 Jun 13 at 21:20
  • 1
    @Programmer66 Oops...you’re right. See changes in my answer. – Lee Sam Jun 13 at 22:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.