What is a sustainable exterior roofing insulation that curves?

Once the stuff has cured it’s considered pretty inert and safe. You don’t want to be anywhere near the stuff without protective equipment while it’s being applied and you don’t want to be in the house while its curing although given you’re going to put the stuff on the outside I would have thought the risk even then would be minimal.

Just a thought. My husband is a contractor and has been called upon to repair leaks in those foam roofs.
The leaks are almost impossible to find! They get under the plastic covering and travel before they show up on the ceiling. A real pain to find and repair.

I read once about insulation made of recycled denim.

I’ve got nothing more specific than that… But it might give you something to Google.

@Seek – the denim insulation is expensive. We went with the nice pink fiberglass when we remodeled. I think it was half the price of denim.

Denim insulation is for interior, not exterior.

Same with pink fiberglass ^^ @Pied_Pfeffer

Sheet foam insulation for exterior is rigid 4 foot’ by 8 foot by 2inches

I wouldn’t call sheet foam, Fiberglass, or spray foam “sustainable”.

Nope, but I expect it to be there for 50 years. (Not like plastic grocery bags: 10 minutes.)

@Judi I don’t understand. Foam insulation is not the roof, so leaks don’t mean anything. The roof has to be applied over the foam.

There are so many roofing materials that I can’t remember the names of the ones I have looked at. I have seen a thatched roof made with cedar shingles. It looked really good but it involved THREE TIMES the normal amount of material. I have seen neoprene roofs (same thing shoe soles are made of) but it is only applied as a sealant to a concrete base, and your house has to be strong enough to support the concrete. Maybe something like this. Once you choose a roofing material, then the insulation is just a matter of convenience. “Sustainable” does not apply.

The OP wants the insulation product over the roof. (Read the question)
There is foam products that can go over the roof but when they leak they travel before they break through, making it hard to find exactly where the leak is from the top.
Our guys spent hours with a hose on different parts of the roof trying to find exactly where the leaks were.

@Judi That is simply not the way to build a roof. When in doubt, hire somebody who knows how to do the job. At the very least, you have somebody to sue if it’s done wrong.

It is the way many roofs are built. Did you even read the question??

Yes I read the question. It makes no sense the way you explain it. I am trying hard to offer something that makes sense. That is why I suggested that you hire someone to do it the way they know is right.

It makes no sense to you because you’ve obviously never seen it. It doesn’t mean the product doesn’t exist.

What is your problem? It is not normal to carry on so much just because you don’t like my comment. Nobody else went bonkers because of it.

@SmartAZ – Spray foam insulation cannot be saturated like fiberglass, so when there is a leak in a roof, the water travels along the insulation until it finds a path to the ceiling beneath. Thus, the waterspot on the ceiling can be many feet away from where the actual leak is, making it difficult to locate to patch and repair.

Is that more clear?

@Seek, he doesn’t believe there is a product where the insulation goes on top of the roof.

@SmartAZ, I am a junior architect, so I AM the one who is hired to do it the way I know is right, and our contractor wants to use the spray foam insulation; probably because of the complex curve of the roof and spray foam’s high R-value (it’s very insulative) Today it is common practice to insulate roofs on the exterior of the structure especially when you have high-performance energy efficiency goals or when you want to express the structure from the interior. I have been researching other insulation options that can be on the exterior of a roof and conform to curves. Haven’t found much besides the spray foam. Thank you @Judi for your advice about leaking. I wonder if there is a solution to that problem…

Ok, you are talking about things I never heard of. I did not realize that at first.

@adr There is a problem if you attach the insulation directly to the roof because the Sun’s heat is focused on the roofing material without an air gap. I had additional insulation added to my home, it is a sandwich of insulation a with metallic coated Mylar on either side of the insulation. The installer specifically did not attach the insulation to the rafters but nailed it to the joists. He said another company use to install the insulation to rafters and the shingles were “cooked” after a couple of summers in North Carolina.