Josh -
I am currently building a home with a butterfly roof. Not only is it a butterfly, but it drains toward part of the house that intersects the roof. So you can imagine that I was quite concerned about water. I decided to go with a spray on polyurethane roof. Not only is it monolithic - there are no seams and they spray around all penetrations, so no flashing issues - but it also provides an R value of 6 per applied inch. After the poly is applied, they coat it with two layers of elastomeric coating, and then granules for traffic resistance. Five days after my roof was done, my framer dropped a 2x12 on the roof, leaving a pretty good size ding. But since the foam is closed-cell, unless the penetration goes all the way to the substrate, you are still leak free. It rained 3 days aftyer the ding incident, and I had no leaks. I'll get around to repairing it sometime... Additionally I had the roofer apply the foam about a foot up the wall that intersects the roof. I'll never have to worry about water penetration up there. Also, with a foam roof you can spray crickets rather than construct them from wood and substrate (within certain limits). Clearly, I would highly recommend it.

-R.

Thanks for the foam idea, sounds like a great product.

I am having a bit of a hard time finding a supplier in my area, but if I can track one down, I think I will give it some serious thought.

Josh