I have hot water radiant heat in a concrete slab that leaks occasionally so I can‘t put carpet on it. Do I dare put ceramic tile over it? Maybe the tile would keep the moisture down.
If you are positive it is leaking do not put anything over it. Fix the leak. It is not as bad as it sounds. If you know exactly where the leak is it is relatively easy to cut the concrete and repair the leak and then re-surface that area. Covering a leak with ceramic tile will only trap the moisture underneath it and eventually mold will develop in the grout joints.
You may want to make the first answer the best answer now because you probably won't get a better one. Covering it is a short-term fix and the moisture will continue eventually not only forming mold but the tile will come up.
You could I would do some research though you need to make sure its not a water soluble adhesive and that the ceramic tile wont get super hot. I know that ceramic is very hard and it should stand up. I am not sure about the adhesive though you would have to ask someone about that. Some one at like Lowe's or home depot should be able to tell you that though. Lay some of the tile out and let it sit on the floor see if it is the best material to use for tile and if it holds the heat like you want it to.
Ceramic tile is installed on concrete slabs all the time and it is a good fit. I would agree with fixing the leak first; however, more than this, if it is an older system and the pipes are copper or steel (rather than pex tubing) then the system is not going to last and the occasional leaks are a sign of a system failure. You will have to decide if you want to replace the system with a new radiant floor above the existing slab or you wish to proceed with some alternative heating/distributing system. This you might want to decide before you consider a ceramic floor.
