View Full Version : Supply 3 shower heads with 1/2" pex

06-23-2010, 08:36 AM
I am in the middle of a bath remodel. The original copper lines in the wall for the shower had the 1/2" supply for hot capped, probably due to a leak or low pressure. It was done when the house was built. They put a T on the garden tub stub up which is in the middle of the floor and ran that line under the shower pan to the shower wet wall next to the cold supply. When I tore out the tub and shower I discovered that I have no way to supply the new shower. The water heater is on the other side of the house, and this remodel bath has no attic.
I don't want to tear up the slab if possible.
Can I run 1/2" pex off a 1/2" copper supply under the sink through the wall and still get enough water to supply a 3/4" valve and 3 separate volume controls feeding 3 shower heads? Will I lose volume through the pex connection, or the 15' of pex I need to do the run?


06-23-2010, 12:11 PM
Doesn't sound like a good idea, 3/4 should be run to the area and 1/2 taken off for each valve, sorry.

06-23-2010, 04:30 PM
Unless you're running Upnor, you should be running 1" pex lines to that valve to really take full advantage of the 3/4" copper inlets, otherwise you may as well just use a regular rough valve with 1/2" crimp inlets.

06-23-2010, 05:49 PM
Have you LOOKED at 1/2" PEX? The opening in the pipe is really about 3/8", (and the insert fittings reduce it even more, especially if you use the plastic ones), so you will get minimal flow to your valve. 1/2" copper would probably deliver adequate flow to your 3/4" valves because of the internal opening sizes, but PEX has between a half and two thirds the capacity of copper.

06-23-2010, 10:27 PM
...and that's why I said 1" pex was needed to do it properly.