Torching over aluminum coated roof?


#1

Recently came across an old brae roof that has been previously coated with aluminum fibered coating.
Customer has inquired about torching a modified bitumen 250 cap sheet granular surface over the old roof rather than coating it again with another layer of aluminum fibered paint.
I myself have never done this, and would think that there is a good chance that it would blister in the future.


#2

Hmmm, my guess would be to torch the surface of the existing roof to “burn off” as much of the aluminum coating as you can while doing your best not to overheat the membrane or catch the place on fire (use a quick back and forth motion with your torch so you just start to heat up the membrane surface). After you have “torch primed” the membrane you will likely have to prime it with an asphalt based primer. Then you should be able to torch a new sheet overtop, but I’d do a test area first.


#3

Install a base sheet first.


#4

Just make sure you don’t breathe that stuff in…yuck


#5

Fix blisters, prime, torch.


#6

Axiom,do you think just priming it will work?I know that torching the paint will make it flake,not allowing the cap sheet to bond.Just asking if the primer will secure this bond?


#7

I would install a base sheet. It is simpler, faster, and more secure.


#8

Yes primer will work if the old membrane is in decent shape to begin with.

AaronB’s solution is the better one though.


#9

i agree install a base sheet to be safe
http://www.texaseliteroofing.com


#10

Cold Mb adhesive over a sound older modbit is ok and wont poke a billion holes in the existing roof. Other wise if you must torch to it then id do a few test areas and see how it looks and peels up first.
The base would be a safe bet I just hate pokin holes.