Hi. I am building a new house, slab on grade. I am trying doing a lot of the work myself. I want to install the water lines under the concrete. What I am wondering is: with pex tubing, can I run a line to (example)one faucet, T in a connector, (above grade) and continue on, back under the slab,to the next faucet or fixture, or should they all be separate lines, with a manifold at the main supply?
I hope this does not sound too confusing! Thanks

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Originally Posted by momsie

Hi. I am building a new house, slab on grade. I am trying doing a lot of the work myself. I want to install the water lines under the concrete. What I am wondering is: with pex tubing, can I run a line to (example)one faucet, T in a connector, (above grade) and continue on, back under the slab,to the next faucet or fixture, or should they all be separate lines, with a manifold at the main supply?
I hope this does not sound too confusing! Thanks

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I ran separate lines, gets hot water to the faucet faster. And you can put ball valves at the manifold to shut off each line by itself to work on. Trying to run several things from one line via a "T" you could have the problem of reducing pressure and volume if several faucets are running at the same time, So you would need to size the lines, start with 3/4 dropping to 1/2 as you go. Less of issue using a manifold and separate lines. Just run a 1/2 inch for each. A bit more expensive but I felt worth it. Remember with slab construction you only get one chance to get it right.

You can do it both ways:

1. Install manifold in one location and run dedicated branches to each fixtures.
2. Loop you pipe from fixture to fixture

It is important that you size your pipes properly. Install 1" main manifold and run all branches in 1/2". I think this is preferable method.

Install plastic sleeves where pipe penetrates concrete to keep it from direct contact with water pipe. ( We made it a habit to sleeve entire length of pipe ). Always pressure test before the pour.

Hi Momsie:

Here is a link to the manual for RESIDENTIAL PEX PLUMBING DESIGN.

http://search.aol.com/aol/imageDetai...playCount%3D20

You need to scroll down the page until you find: FREE Residential PEX Water Supply Plumbing Systems Design Guide. It is located in middle column 1/2 way down above the picture of 2 water heaters.

This should answer any of your questions, but if not drop back and let us know where we can help.

I usually run a 1" pex manifold but run 3/4" pex out to all fixtures (except toilet) as we found that 3/4" pex fittings actually have an inside diameter similar to 1/2" copper tubing and when it comes to a SHOWER you want as much volume as you can get... ;)

Anyway, check out the manual, let us know what you think...

MARK

THANK-YOU very much. Your advice and help is appreciated.

Hey, Mark, good link !

Hi guys:

Glad everyone liked it. The manual is over 128 pages if I remember correctly and answers most residential questions!

Have good day all... ;)

MARK