Step 5 · Prepare for New Valve Installation
Prepare to install the new valve. You will likely need to add a new wood support block (a piece of 2x4 lumber) between the wall studs for mounting the new valve. Secure the 2x4 with deck screws. Following the new valve's instructions, determine the correct setback from the front of the wall studs. This is critical for the trim to fit correctly. Dry-fit the new valve and the necessary copper pipes and fittings (couplings, 90-degree elbows) to connect the existing hot, cold, and shower riser pipes to the new valve. You will also cap the tub spout port on the new valve if you are doing a shower-only installation, or run a new pipe down to the tub spout if applicable. Cut all new pieces of copper pipe to length with the tubing cutter.