T-Joint leaking
 

I have a T-Joint that is half a cm from the ground and behind another pipe. It looks like it has perished on the seam. What would be the best way to fix the problem?

You can try to reseal it by heating it up with MAPP gas or remove it, clean up the connecting pipes with emery cloth and sweat on a new one.

What type of pipe? Copper? Threaded galvanized?

Very very old house i bought. It has still got steel pipes

Can you post a pic of the union?

The pipe is going to have to be taken a part and resealed. Likely it is rusted to bits and is about to really bust and leak.
Can you post a picture?