The fabric was 1.1 ripstop nylon and seems to be holding up pretty good although to be honest it hasn't been used in very harsh conditions. I've treated it a couple of times with fabsil. The first time I used it in a heavy rain it did let through a fine 'mist' of water vapour, but that was a long time ago and it only had one coat of fabsil back then, I have a feeling that if the rain is very heavy it'll just force it's way through as the material is really quite thin. But I'll just keep on putting layers of fabsil on and give it a test with a hose come the summer.