Monolithic fiberglass flat roof, residential

A new construction home nearby has the flat roofs done with resin over fibreglass cloth over plywood substrate. The builder’s onsite guy said they’ve used it for awhile, gets finished with a gelcoat just like a boat. I don’t think they’ve used it long enough to know how it holds up when the building settles.

I googled it and it looks like they use it in the UK, found one stateside reference in Utah.  

Anybody with any longterm experience with this?

Are you sure it was resin? I know of some fluid applied systems that use a clothlike mat…some good, some not so good.

The builder’s foreman told me it was resin. Said it was similar to boat fiberglass. He said it prices like acrylic fabric treatments. I’d like to talk to the sub.

Not new. This has been tried for years in various forms. One consideration to be concerned about is its rigid finish.

When you say it “has been tried” are you saying “with questionable results”? The builder of this spec house will probably have his money out before problems develop but I am asking as a homeowner.

You should look into polyurea mambranes.

been alot of fiberglass roofs goin on here in central florida, for about the last 8 years or so. i havent seen or heard anything bad about them.
makes a great deck. just like a boat deck . easy to clean. very durable.
and we all know how long fiberglass last.

i like em.


How long, gweedo? We all know the glass fibers will last foreever, but the resin and gelcoat will soak water.

fiberglass has been out since the fiftys.
i dont think it has to prove it self.
its great material.
they make cars with it, boats with it, you can beleive they can make roof decks out of it.
i havent seen a car made of foam yet. i dont rule it out for the future though.


Who said anything about foam? :shock:

Anyhoo gelcoat sems too rigid to perform well for roofing. I know it cracks and the assembly soaks water.

Oh yeah, the trim on car bumpers are Reaction Injection Molded polyurea.

thought that mite ruffle your feathers.
i disagree that once the gellcoat cracks its gonna leak, i have a 1976
houseboat with cracks in the gellcoat all over and theres no leaks or staturation.
as far as the foam goes , i could have used torchdown. same thing, its not as durable as fiberglass.

as far as your plastics go. i like their evolution, but id still keep it in the shade as much as possible.


Ruffled feathers> when was that?

Kepp it in the shade? What do you mean?

A fiberglass roof is, in my opinion, a really bad idea. Yep, fiberglass has been great on boats and cars, but try anchoring it to the parapet or other walls. Too rigid. If every roof stayed square and never moved, any product would work. Unfortunately, most structures move. On a boat the structure flexes within itself, on a deck it is horizontal and the stress is straight across the flat sheet. No doubt the material is tough but I’ll have to pass on using it on a roof.