FRP Roof Covering

We added on to our old farmy Italianate house. It's mostly done now - I still need to add a few layers of trim and some corbels. The original house has a Medina sandstone foundation I built the addition foundation of the same material. The elevations of the addition ended up pretty close to two existing second-story windows that I didn't want to move. It left very little possibility for slope on the roof. So we built a hip roof with the lowest slope being about 1-1/2:12, and the steeper side slopes are about 2-1/2:12. There's not enough slope for any regular roofing except for products used on flat roofs. After a bit of research, I found that it's really common to use FRP(fiberglass reinforced polyester), AKA fiberglass in the UK, so I gave it a shot. Most of you know I come from an automotive background, and I'm experienced with fiberglass resins and fiberglass mats/ cloth. Still, there was a lot to learn. I learned a lot about the different resins, cloths, and appropriate weights. It was a fun diversion from peel-and-stick or modbit. The roof is two layers of 1708 cloth installed with polyester resin. It's about 220 ft. I used 14 gallons of resin. I pre-made the flashings and installed them first with fiberglass cloth and resin. Learning how much resin you can put down at a time was the most anxiety-ridden portion of the project. Once the resident cloth was installed, I protected it with two coats of gel coat—the top coat contains what's referred to as wax. The wax is a mixture of styrene and paraffin wax dissolved in acetone. You mix that into the top coat of gelcoat, and the styrene and paraffin rise to the top during the cure. They create an airproof layer that allows the gel coat to fully harden rather than remain slightly tacky. I'm fully aware of the pedantic nature of this crowd. The siding is all different colors because I had enough scraps from other jobs to fill it in.

source https://www.inspectorsjournal.com/topic/19809-frp-roof-covering/?do=findComment&comment=183098