I am installing 2 layer torch on roofing on my new plywood carport. I am using IKO-TP-180-FF-Base modified bitumen membrane and the IKO torhflex.SBS for the final layer. My question is… Can I torch the IKO base directly to new plywood?? Or do I nail down a layer of something to the new plywood first? Thanks in advance for any info.
I know of people that prime the deck and torch directly to it, I wouldn’t.
We use 1" round steel cap nails to secure a 75# fiberglass base sheet, then torch to that.
It would be safer to use Armorbond 180 peel and stick base sheet.
Prime plywood with self adhesive membrane primer first.
Tumpline - He is using torch down. Axiom had the right info.
Isnt Armorbond 180 is a peel and stick base sheet membrane?
You need to nail a base sheet over the plywood first. If you attempt to torch directly to the plywood , you will burn the structure down.
I’m not familar with that Trumpline. You could have the right product. I was just going off what he wrote. 
one layer of torch underlayment and one layer of torchdown.
pilin up a bunch of layers is goin to make for an unrepairable mess.
dont like 2 layer torch.
dont like it indeed.
gweedo.
Nailable base sheet and torch cap sheet over it .
blackout board
base sheet
torch down (granular)
don’t forget about your tie in, if there is one
The rest of the world uses torch on base sheet. All but the US.
They prime the wood and torch to it. I have never done this, so I am not familiar with the installation practices, nor with the primer, which is supposed to make the wood deck fire retarded.
I know it is done with a lot of success around the globe, but with no first hand knowledge, I cannot recommend this nor how to go about it.
Well appreciate all the input regarding my question. I have since asked a few friends who have installed 2 layer torch on and they all said they torched directly to plywood. Being extremely carefull obviously. However advice from roofers on here say contrary. So I am not sure what to do?? Roofers definately are in the know as they do it regularly.
Cheetah I have been installing modified bitumen for over 20 years.
I have never torched directly to the plywood,however i have seen it done quite often.
I have also seen places go up in smoke as a result of torching to plywood.
I quite often use the two ply modified bitumen system with the peel and stick base sheet membrane.
I prime the plywood with self addesive membrane primer, install peel and stick base sheet membrane and torch apply the cap sheet.
The base sheet is fully adhered, cuts down the risk of fire, and IMO is a great system if done correctly.
What is the advantage of torching or using a self adhering base sheet if you have a nailable deck?
I prefer to have my base sheets fully adhered, be it peel and stick, mopped in with hot asphalt or with cold applied adhesives.
Ive come across a few nailed in base systems that had major shrinkage and had pulled away from scuppers, pipes etc causing leaks.
maybe they were not installed correctly, I have never installed them that way so I wouldnt know a good install from a bad one.
I like the fact that when I install the base sheet and pull the paper from the seam and roll it, its watertight.
[quote=“tumpline”]I prefer to have my base sheets fully adhered, be it peel and stick, mopped in with hot asphalt or with cold applied adhesives.
Ive come across a few nailed in base systems that had major shrinkage and had pulled away from scuppers, pipes etc causing leaks.
maybe they were not installed correctly, I have never installed them that way so I wouldnt know a good install from a bad one.
I like the fact that when I install the base sheet and pull the paper from the seam and roll it, its watertight.[/quote]
I call bullshyte! I have never seen modified bitumen shrink issues, and MB pulling away from the metal is most likely due to a lack of proper priming or heat.
I would never trust a base sheet as watertight unless it was mopped down or with SA if on a 3/12 pitch or greater.
Ring shanked nails have never pulled out on any roof I have ever done.
[quote=“AaronB.”]
[quote=“tumpline”]I prefer to have my base sheets fully adhered, be it peel and stick, mopped in with hot asphalt or with cold applied adhesives.
Ive come across a few nailed in base systems that had major shrinkage and had pulled away from scuppers, pipes etc causing leaks.
maybe they were not installed correctly, I have never installed them that way so I wouldnt know a good install from a bad one.
I like the fact that when I install the base sheet and pull the paper from the seam and roll it, its watertight.[/quote]
I call bullshyte! I have never seen modified bitumen shrink issues, and MB pulling away from the metal is most likely due to a lack of proper priming or heat.
I would never trust a base sheet as watertight unless it was mopped down or with SA if on a 3/12 pitch or greater.
Ring shanked nails have never pulled out on any roof I have ever done.[/quote]
Call it what you want, i couldn’t really care less.
I find hard to believe that you have never seen a modified roof that had any major shrinkage issues with vast roofing experience you have.
And I totally agree modified separating from metal is a result of poor heat/lack of primer.
I sleep well each night even if cap sheet has not been installed, i bleed the last inch of seam with a torch and trowel paying particular attention at end laps etc.
Now I have seen some major shrinkage with non reinforced EPDM. I have seen tears from building movement on large roofs with no expansion joints, but no massive shrinkage issues.
Am I alone in this?
uh oh… no comment.
[quote=“AaronB.”]Now I have seen some major shrinkage with non reinforced EPDM. I have seen tears from building movement on large roofs with no expansion joints, but no massive shrinkage issues.
Am I alone in this?[/quote]
While I am sure there are some membranes out there that do shrink I haven’t seen any of this.
The issues I see with torch applied modified are workmanship related, seams coming apart and the membrane separating from the perimeter metal.