First of all, I'm from Europe, so please forgive me if things I'm about to explain seem foreign to your part of the world.
Yesterday, I noticed that one of the two valves (the hot water one) under my bathroom sink was leaking very slightly. My first instinct (not so bright, as it turned out) was to attempt to slightly tighten it. That made the matter worse.
After closing off the main supply valve and taking the valve out, I saw that the joint in the wall had developed a break:
Mind you, this is not a dry wall - it's a brick and mortar wall, which means replacing this will be a mess. Because of unfortunate positioning of the joint, it would require removal of 4 tiles and a fair amount of demolishing to free up enough room around the joint and adjacent pipe. I'd desperately like to avoid this, but I'm afraid I probably won't be able to.
Still, I'm asking international DIY-ers here: is there a realistic way to seal this break without having to replace the whole joint?
The fitting in the wall is similar to one of these: