Commercial plumbing repair. Water is leaking from inside the cafeteria women’s bathroom behind the single vanity, pretty badly. Inside a block wall, which is an interior wall, but seemed frozen and cold air was blowing from inside the block wall out into the ceiling. In order to stop the leak, I had to shut off the entire building from the main, and was able to cut 1/2” isolation valves into the ceiling piping to shut off the branch line to the lav and restore water to the rest of the building. Because the wall appears frozen and the pipe may have frozen and burst, I told them we will return when the weather breaks to make the repair and get the lav back in service. Everyone agreed it was better to wait until next week to make repairs, so it doesn’t happen again before warming up.