SBS Cold or Hot Torch

hi all -

Anyone care to share. Torchdown superior to cold applied ?
I like the premise that torchdown get’s all hot and gooey so theoretically, it’s a better way of adhesion ?

Its down to 2 roofing shops.
Total different approaches though.
Both full teardown and re-roof

A: Ice Membrane Sheet ontop of Iso board, followed by SBS white granulated
Maybe it’s just marketing, but 40 year warranty

B: Still waiting for official bid, but 2 Layers of Hot Torch ontop of Iso Board. He did specify the 1st layer of rubber is a base rubber. He recommends going with non granulated rubber, and then alum coat on top.
10 yr warrannty

I asked Roofer B about cool roof coatings, and he said something along the lines of manuf. warranty requiring alum. coat.

I like roofer B more - as he seemed more interested in the job details, the devil in the details.

APP torchdown is far superior.

Roofer A is shortcutting.

I always install a layer of 7/16 OSB of my Iso board. What is needed is a 2 ply minimum, 3 ply is better, roofing system. 1st ply (layer) is your base. The past is nailable and is fire resistant if using torchdown. And yes, you will want a granulated cap layer. APP Modified Bitumen. Don’t cut corners or you will be paying for it later. EVEN if you choose the right material, it is my experience that most contractors install it wrong. I tear off year old torch downs all winter long.

I recall a blurb from another roofer who did SBS

His reasoning was

APP is more plastic than rubber
APP does not play well in the northeast winter, hence you see the microcracks/fractures/spiderwebbing on the surface
APP if not done right more often than not, too much heat, cracks on sealing edge and or his opinion…APP has plenty of air pockets on install.
He also said APP is cheaper than SBS materialswise ?

BTW, I don’t know how “roofer B” is able to do the install with APP as I thought it was illegal out here these days. I know on steel or metal decks it’s not. Still awaiting his quote but it I believe it was something to the extent of whatever he was applying past the iso board that made it “legal” for him to utilize the torch

So you’re saying granulated APP is the way to go ?

Expert -

I looked into this 2 years ago. Got really discouraged as 9 out of 10 roofers just wanted to cut air pockets, nail them down/patch and then dump another layer on.

I’m looking for one to do a full tearoff, proper flashing, etc and almost all them said just wanted the easy way out with a new layer ontop.

Sofar, the 2 shops in the OP are the only ones even mentioning tearoff. All the others, is the same old, same old…

Tear off and start from scratch is the ONLY way to go with this. I even refuse to install asphalt shingles on a pitched roof over an existing layer. If you are content with one of these two guys then go for it, if not keep searching. Once you fins the right person you will know. God how I despise poor quality contractors, but like you have experienced yourself. Its like 9 out of 10, just want to make a quick buck and have no regard to quality or giving the client something for their money.

What is the benefit of a mid ply sheet if going with 3 ply APP…

I’ve got AC condensers+ electrical that need to be uninstall/reinstalled IMO to do the job proper.
Between hvac and sparks, that is another add-on expense that is part of the overall…don’t even get me started what HVAC wants. — aka, will I see a better sealed roof with the mid ply, and OR it’s only as good as what the top layer holds up

The extra ply will make it more durable and last longer.

Thx Axiom. Just for clarity, when I say extra ply, how that does add to the value/benefit on how long the cap sheet will last ? Ultimately, while all components down to wood is a ~system~, the primary part of ingress will be the cap sheet.

Aka, will by me adding more to the cost, with a mid layer, add to the longevity of the cap sheet lasting longer ?

The electricals, Hvac are another expense. I will need them disconnected and then reconnected.
I’d like to minimize this cost depending on what ROI I get out the roof system. If the mid layer adds a certain X years of longevity to the cap sheet, then it’s worth it.

The mid ply is simply smooth modified bitumen, when the cap sheet is installed it is heat fused or melted to the mid ply essentially making the wear surface 2x as thick.

This adds at least 10 yrs to the life of the roof providing everything is done correctly.

One thing many do not do when installing granulated cap sheets is to embed granules in the bleed out on the seams, this leaves a small amount of modified exposed to the sun and this part deteriorates first and quickest.

1 Like

Gran. is the way to go ?

Roofer B: Pitched APP smooth with alum. I asked him both about granu and ultrawhite coat.

He said gran. is more messier with the granules.
Advised. alum is the coating he would use and only recommend within his warranty period of 10 years. And also to stay within manuf. warranty guidelines. I was advised anytime after 10 years, I could use anything I want

It depends on what you want it to look like.

Granulated usually looks better.

Granulated cap sheets are a little harder to work with.

There is the granules in the bleedout I already addressed and when 2 rolls need to be joined the granules where the seam is going to be need to be embedded into the sheet before seaming.

These are things frequently not done or done inadequately.

Torchdown Modified Bitumen is a really good product when installed correctly, the weak areas are the seams and the perimeter metal.

Many times people don’t prime the metal so the mod bit doesn’t stick to it.

I recently looked at boathouse where the entire mod bit roof blew off because it was applied to 30# felt secured with roofing nails and the edge wasn’t stripped in.

Won’t see the rooftop unless one’s operating a drone :wink:

Coatings - whether it be alum. or elasto is not good for granules.
I don’t mind the maintenance of painting either as I do go on the rooftop once during spring and once late fall just to hose the hvac units out.

On roofer B whose pitching the APP, I’ll re-inquire about the granules and his opinion on it. I suppose if he liked/preferred working with it, he would have pitched it.

Going back to your last 3 line items, yeah, the devil is in the details

I did a 2 ply mod bit almost 20 yrs ago, it got coated 3x because I bought too much, that roof still looks as good as the day it was installed.

Coated smooth mod bit is a very good product also.

Maybe I should start a new thread…but let me reply here 1st

Had Roofer A come back out - Cold SBS. Want to review his install details - base sheet, ice/water membrane, cold applied. I asked him about torch, because AFAIR, torch is illegal , torch is allowed on concrete or steel decks…

Roofer B whom is proposing APP, I asked him the very same question - isn’t what you’re proposing illegal. I think he worded it , that either his base sheet that he applies - makes it a way ~legal~ for him to do a torch application.

The ? for the forum members - is roofer B just skirting the issue and technically doing a illegal install.

Well like I said the first time the cold process guy is short cutting.

You don’t use ice & water shield with these materials.

For me that alone disqualifies him.

Is there a reason you aren’t looking at EPDM?

IMO EPDM is far superior to cold process mod bit.

It’s hard enough finding a roofer willing to do a tearoff if not be confident about that…

I looked at EPDM briefly.
I recall it was great for large commercial flat roofs.

Contraction/expansion rates on EPDM were huge.
Proper install, as it can’t be fully glued down, etc, etc to allow for the expansion, etc.
I can’t recall exactly , but I believe it was supposed to be floated to some extent to allow for such expansion/contraction

I’ll edit this when I get home and dig up some notes I wrote down when I looked at this awhile back

You did not understand what you were reading if that is the case.

Fully adhered is the only way I install EPDM, since it is the best way.

Torchdown is being slowly phased out, not because it isn’t a good product but because there are too many inexperienced installers burning buildings down.

Thanks Axiom. Off the hunt to find a tradesman familiar with EPDM.

For my own wiki, mind advising is it just industry wrong , etc on the Roofer A : Iso / Ice&Water shield/cement/SBS

Roofer A basically says he could lay down iso, then the shield and if it happened to rain that day, water would not even get past that.

----this was the notes I saved on the blurbs I came across re: EPDM
EPDM was originally created and intended for large warehouse roofs with a minimal amount of foot traffic and a minimal amount of cut-outs.

EPDM comes in sheets that are 10′ high X 100′ long. Unlike other roofing materials, EPDM is not adhered by glue, adhesive or tar. The reason is EPDM’s high concentration of rubber expands and contracts at a much higher rate than any adhesive glue or tar on the market. Therefore, it needs to float on the roof to prevent it from prematurely deteriorating. The glue that is used in conjunction with EPDM is only to be used on seams, cut-outs and low parapet walls. Some contractors glue all the EPDM to the roof decks, this is a great injustice to the homeowner. The reason is that the glue expands and contracts at a much lower rate than the EPDM membrane itself,
causing a conflict between the glue and the membrane and also causing a guaranteed premature deterioration of the roof system itself.

EPDM is first cut to the width of your roof. Including parapet walls. For example, if your roof measures 20’x 60′, you will have six 10×20 foot sheets of EPDM installed.

EPDM is then mechanically fastened at each 10 foot seam with a screwed down windbar and a sealing tape. The parapet walls (if any) can be glued on. All cut-outs will be sealed by glue and a special caulking adhesive. So in between each 10’x20′ sheet is a hollow non-adhered membrane with dozens of screws fastening the seams. If there is a leak (tear)on the front of an EPDM roof and the slope is going toward the back of the house, you can be in big trouble. If the tear is large enough it is possible for the water to travel underneath the whole system causing leaks in every room of the house.

Over the years, this EPDM roofing system has been nothing less than a nightmare for residential roofing when a leak occurs. And leaks could be caused by many things such as fireworks, foot traffic, cable dishes, atennas, sharp edge tools, falling branches, etc.

Got a couple more roofers in today

Another SBS showed me a stackful of newspaper articles on torching, fires, etc. He’s advising ist’s illegal, especially on a wood deck, etc, etc. Wanted to pitch me a silicone coating before I told him wanted a tearoff.

Another roofer, after I showed him the HVAC and told him we’re investing $$ alone just getting the condensers disconnected and reconnected, pitch the following
2" ISO, 2 Ply SBS, and got pretty agressive in price that included alot of stuff that latter are add-ons (capping details, gutters, etc). I don’t know if they were the right fit…

Last roofer for today. Torchdown. I state torch, as all the SBS guys are advising it’s all illegal, jail, fines, etc. Different approach to certain things. He says he prefers to go with Granulated APP and not smooth. Advised why paint, if you don’t have too. (I’m fine with painting every X years if it is superiors to Granulated) over the long term life of the room.

Waiting for the last roofer to call me back, which I believe does EPDM as his trade,