I managed to damage the outside of an underfloor heating pipe whilst chiseling the screed today. Im confident it wont leak (right away) but its certainly weakened. I have seen electricians use what I guess is some sort of resin when making joints that will be buried underground and wondered if there was a product that I could simply pour into the hole in the concrete where the damaged pipe is. This would obviously save me chopping out even more of the floor to get a joint in. Anybody got any ideas?