In another thread I mentioned I am doing a repipe of my supply line from polybutylene to PEX. The work is to be done in a very low clearance (14" crawlspace and spans about 50' between where the water comes in and the garage where the manifold will be located.

In order to avoid dragging the PEX tubings back and forth inside the crawlspace, Packy has previously suggested installing some larger diameter PVC pipes as sleeves then pull the PEX tubings through.

I am going to do the PVC pipes and tomorrow I will do another trip into the creepy crawlspace to figure out where to install these pipe sleeves.

First of all, I am thinking using 3" PVC pipes, two of them, one for cold one for hot.

I am going to mount these pipes so that the PEX tubings will be running right below the floor joists.

How far apart should I mount these PVC sleeves? One every 5 feet? 10 feet?

Is it OK to use these adjustable hangers to hang these sleeves or do I need something more heavy duty?

OK, here we go..

cut a piece of PVC pipe to span 3 joists. 33 1/2 if joists are 16 on center.

45 the ends of the pvc.
drill small holes in the top of the pvc.
secure the ends to joists above. this is the reason the ends are 45 deg.
skip a couple of joists and repeat.
pull/push pex thru
loosely tie wrap the exposed pex between the pvc sleeves (optional)

i hope to under stand mu drawing.

Thanks Packy!

I have no trouble understanding your drawing. Makes perfect sense.

The only thing is how many of these do I need? If you say each spans three joists, then skip a couple and repeat, then along the entire path I will have say half the length in pipes and half exposed? So if the path is 50' long I will need to put in a dozen of these 30" sleeves?

sum, i didn't word that correctly.
the maximum spacing between supports for pex is 32 inches.
so if you are running pex below the joists (no sleeve) you would clip every other joist.
so skip one joist with the home made sleeves not 2.
i would use 2 inch pvc. you can cram seven 1/2 inch pex tubes into 2 inch pipe.
i may have read that you were running 50 feet but i didn't pay attention.
for that distance i think i would use 2" x 20 feet pvc coupled together to make a 40 foot sleeve.
then use a few short sleeves at the end.
don't worry the pex will push thru just fine and it will not rattle around causing hammer noises.
plastic clips with stainless screws will hold the sleeve in place forever.

Packy, I plan to use 3/4" PEX tubings. The run is 50' at the longest. But some runs are shorter, with some common paths.

I think the maximum number of pipes will be four 3/4" tubings (cold) and three 1/2" tubings (hot). So I am thinking to run two pipes one for cold and one for hot. Do you think I should use 2" PVC for four 3/4" PEX? I assume mixing hot and cold all in one pipe is not a good idea?

sum, cold and hot in the same sleeve is not a good idea.

i have never tried multiple 3/4 pex inside a sleeve so i can't really say.

when i run 3/4 pex, i almost all the time use fostapex. it has an aluminum layer on the outside so when unrolled it pretty much stays put. (unlike wrestle pex)
it does require a special tool to peel the outer layer off but what it saves in not having to fight the pex rolling back on itself is amazing.
[www.globalpipe.de]

I am thinking of two PVC pipes sleeves, one to run cold tubings and one for hot tubings.

I went to the crawlspace today and explored a bit to figure out the best path. I did see an issue where a foundation wall is in the way of the tubings, and the floor joists changed direction after that foundation wall. Now I have to figure out if I need to chip a hole in the concrete foundation wall or drill a big hole in the blocking to pass the tubings through. Life is never straight forward and always full of surprises.

sum, do you have room at the entrance of the crawlspace to assemble and slide in a 40 foot length of pvc (2 @ 20 glued together) ?

Not enough room. The crawlspaces are separated by various foundation walls. I have one foundation wall that is blocking the path and I need to figure out how to make a straight path without having to saddle lower to pass the wall then back up again. I might have to drill large holes in the wall to pass the sleeves through.

sum,


either:


simply replace the Butyl with PEX keeping the same 'layout' and penetrations


OR


get two helpers to minimize trips

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Bernabeu,

I can't keep the same layout as the old PB tubing. The old PB tubing runs all over the place with tees everywhere.

The new PEX will have multiple runs because I am doing home runs so will take more pipes but almost no intermediate joints.

The only issue is my plan of running the PEX tubing along the bottom of the floor joists requires some rethinking because there is a foundation wall in the middle and the floor joist changed direction so the first joist after the direction change blocked the path of the PEX. I might have to drill holes or figure out a way to use existing holes in the wall. This is a picture taken inside the crawlspace.





Edited 1 times.

sum, can you lay the sleeve on the ground. a piece of pvc with 45's looking up on either end
the 45 (or two 22's) at the inside end can be assembled after pushing thru the existing hole in the wall.
i know you at some point talked about ground water. but if the pipe is glued well with a few cement blocks holding it down that should not be an issue.