[RRH]

I would still use the attic. All you do is run them inside PVC pipe.

If you like you can buy pipe insulation in any size.

You said they would be going into a utility room. So run the PVC just out the ceiling.

You will have protection from any leak coming thru the ceiling. Which can do the worst damage.

But with PVC should not ever have a break. Since the PVC also give you future rodent protection. Some rodents are known to chew thru pex.

If you dont want pipe insulation. A small amount of heat from inside the utility room will migrate thru the pipe for even more freeze protection.

 

[Anti-wingnut]

I would still use the attic. All you do is run them inside PVC pipe.

If you like you can buy pipe insulation in any size.

You said they would be going into a utility room. So run the PVC just out the ceiling.

You will have protection from any leak coming thru the ceiling. Which can do the worst damage.

But with PVC should not ever have a break. Since the PVC also give you future rodent protection. Some rodents are known to chew thru pex.

If you dont want pipe insulation. A small amount of heat from inside the utility room will migrate thru the pipe for even more freeze protection.

PEX is much more freeze-break resistant than PVC.

The slab could be a PT slab, so that's a big deal.

 

[DIYOkie]

Ok fellas...I been doin' some hard thinkin'...and I had an epiphany!

Really, realizing the R value of drywall just changed everything for me. 1/2" is around .5

So, the R value of a 2 x 4 wall with R13, is 13.5 if you dismiss the sheathing and siding, which don't add anything really anyway. As a thought experiment...if you ran pex right on the drywall inside your house, you'd never have a frozen line. It's right there exposed to the warm air along with the occupants, insulated by a R13.5 wall.

So..if I ran pex by notching my 2 x 6 studs so the pex is right on the surface of the inside of the studs, then run R19 in the wall cavity, I now have a line sandwiched between a R .5 drywall layer exposed to the warm air, and a R19 wall insulating from the outside.

That seems obvious that my 2 x 6 wall with notched studs is even more insulated than the 2 x 4 R13.5 thought experiment above. The only thing blocking the warm air of the house is that pitiful R .5 layer of drywall.

And, of course, traveling down a ceiling cavity is the exact same thing - staying on the "warm side" of the R30 with a layer of R .5 drywall for the warm air to penetrate.

The key here, to me, is notching the studs so the pex is traveling along the face of them, so the whole R19 cavity is separating it from the cold, while only a layer of drywall is separating it from the warmth.

I don't see how this isn't even better than a finished 2 x 4 wall with pex ran on the surface of the drywall.

What am I doing wrong with my thinking here?

 

[RRH]

PEX is much more freeze-break resistant than PVC.

The slab could be a PT slab, so that's a big deal.

Not if the PVC has not water in it.
Dont think you understand.
Use the PVC as a chase to run the PEX thru.

It would be very hard for the pex to freeze inside the PVC with some heat going into the pipe. And if it did. Water would be directed by the PVC to the ends of the PVC and save the ceiling from all water damage.

 

[Anti-wingnut]

Not if the PVC has not water in it.
Dont think you understand.
Use the PVC as a chase to run the PEX thru.

It would be very hard for the pex to freeze inside the PVC with some heat going into the pipe. And if it did. Water would be directed by the PVC to the ends of the PVC and save the ceiling from all water damage.

How do you pull the PEX in PVC? Do you use conduit instead?

 

[Anti-wingnut]

What am I doing wrong with my thinking here?

Increasing the chance of a puncture and weakening your studs.

 

[DIYOkie]

Increasing the chance of a puncture and weakening your studs.

From the way we are routing the lines, we'll only have to notch out a total of 7 studs (2 x 6), about 3/4 to 1 inch deep. So, I'm good with that, and it's well within code.

The puncture potential is definitely there, though. I will use the metal plates over those notches.

 

[TheEplumber]

Your idea is fine. But batt insulation does not stop drafts. This is why I use the foam behind the pipe.
I also use 1-3/8" self feeding bit in my DeWalt Timber Wolf. Drill just 3/4" in from the edge of the stud and leave an 1/8" of wood. Looks much cleaner than notches. Put a nail plate over it and you're good to go

 

[RRH]

How do you pull the PEX in PVC? Do you use conduit instead?

I always run it as I am putting the PVC together. Would be to hard to try and fish it thru with bends.

Need long sweep bends and I use 1 1/4" PVC to run a 3/4" pex thru.

Takes all the risks away from having a water line in the attic. Which I sometimes need in a slab home with replacement.

 

[DIYOkie]

Your idea is fine. But batt insulation does not stop drafts. This is why I use the foam behind the pipe.
I also use 1-3/8" self feeding bit in my DeWalt Timber Wolf. Drill just 3/4" in from the edge of the stud and leave an 1/8" of wood. Looks much cleaner than notches. Put a nail plate over it and you're good to go

1-3/8"? Are you saying put both lines in the same hole? I guess that would be fine...I wasn't sure if you were supposed to keep them separated.

Yeah, the wife and I were talking and I decided to do just that - build a sort of box around the lines with the foam board, like you were saying - tight against the studs, foamed at the edges to stop these drafts, and adds just that much more R value too.

A 1" piece is R 6, a 1/2" is R 3.

Now I'm kind of curious about burying a temp gauge somehow...that would be insightful to be able to actually know the temperature of the environment the lines are in. Just imagine the piece of mind of it being 20 degrees outside, and your lines in a box reading 50 or something. That would be interesting to know.

 

[TheEplumber]

1-3/8"? Are you saying put both lines in the same hole? I guess that would be fine...I wasn't sure if you were supposed to keep them separated.

Using self feeding bit, I drill 1-3/8 hole and use one of these. There are more than one style too. Put your pipe through the hole, slip the pound in over the pipe and then- pound it in the hole.

https://www.siouxchief.com/products...roducts/support/supply-hangers/plastic-cts/cts-isolators/ezglide-tube-insulator

https://www.siouxchief.com/products/support/supply-hangers/plastic-cts/cts-isolators/suspensulator

These are good too, but they require fasteners to hold them in place- https://www.menards.com/main/plumbi...upport/sioux-chief-1-2-cts-suspension-clamp-5-pack/557-2pk2/p-1444442678498.htm

 

[Ghostmaker]

If you have no source of heat to the pipes they will freeze. If I stick a glass of water in the freezer and wrap it with 30 inches of insulation it will end up a frozen glass of water with a nicely wrapped ice cube.

 

[DIYOkie]

If you have no source of heat to the pipes they will freeze. If I stick a glass of water in the freezer and wrap it with 30 inches of insulation it will end up a frozen glass of water with a nicely wrapped ice cube.

Yes, and same is true no matter where the pipes come into the house if the house isn't heated, so that's why people winterize for those conditions.

However, if I have a heated home with a sheet of R .5 drywall over the pipe, it seems that will receive the heat from the home. The other side of the pipe will be against R6 foamboard and R19 insulation, so the cold will have a hard time overcoming the heat from the home going through R .5 drywall.

Are you thinking my drywall layer is going to keep the pipes from getting the heat from the home?

 

[Gregsoldtruck79]

I like your plan but what about where the PEX comes across the door header ? That plan changed ? Because the door header IMO, is the only issue I can see...concerning significant heat loss maybe on extremely maybe below zero F. days. . not that it would freeze, but just a hot water temp drop maybe.

 

[DIYOkie]

I like your plan but what about where the PEX comes across the door header ? That plan changed ? Because the door header IMO, is the only issue I can see...concerning significant heat loss maybe on extremely maybe below zero F. days. . not that it would freeze, but just a hot water temp drop maybe.

Yeah, I'm still stuck with that problem, however, now I'm going to use that foam insulation board to create a box system to use the ceiling after all. That will have R30 over it.

I would like to use the floor, but I have no way to channel across the floor. It's 6" thick, and I do not want to cut a 4 foot long 6 inch deep block out of my floor. I just can't accept that. A 2" channel would be cool, but I don't think they rent that concrete channel tool here.

 

[DIYOkie]

Using self feeding bit, I drill 1-3/8 hole and use one of these. There are more than one style too. Put your pipe through the hole, slip the pound in over the pipe and then- pound it in the hole.

https://www.siouxchief.com/products...roducts/support/supply-hangers/plastic-cts/cts-isolators/ezglide-tube-insulator

https://www.siouxchief.com/products/support/supply-hangers/plastic-cts/cts-isolators/suspensulator

These are good too, but they require fasteners to hold them in place- https://www.menards.com/main/plumbi...upport/sioux-chief-1-2-cts-suspension-clamp-5-pack/557-2pk2/p-1444442678498.htm

My original holes were 3/4" thick, maybe 1". I can't imagine going to 1-3/4".

So, what happens if you don't use these suspension hangers? I have a run that's all internal walls and I didn't want to redo that one and I didn't use any of these hangers on it.

I figured being late July in Oklahoma, they're as expanded as they're going to get? Still seem to have room in the holes to expand more...

 

[TheEplumber]

I believe I said 1-3/8 hole and I gave a link to an alternate support. It will fit a smaller hole. You can also face it opposite the hole too and anchor with screws. This should hold the pipe off the wood.
These anchors aren't as important with pex . But are really needed on copper that will rattle or creak in the holes

Sent from my SM-G970U using Tapatalk

 

[DIYOkie]

I believe I said 1-3/8 hole and I gave a link to an alternate support. It will fit a smaller hole. You can also face it opposite the hole too and anchor with screws. This should hold the pipe off the wood.
These anchors aren't as important with pex . But are really needed on copper that will rattle or creak in the holes

Sent from my SM-G970U using Tapatalk

Yes, you did. Was a typo on my part. That alternate support sounds good for that run.

Good to know. Thanks for your patience and help, sincerely.

 

[TheEplumber]

Yes, you did. Was a typo on my part. That alternate support sounds good for that run.

Good to know. Thanks for your patience and help, sincerely.

Glad to help :wink2:

 

[Calson]

I have seen many PEX lines running through the attic and going from one end of the house diagonally to the opposite end. In terms of water damage I would rather have a leak in the attic where it can be spotted and repaired than inside a wall where it could grow toxic mold for years.

Friends has a water pipe in their slab leak and it took more than a month to jack hammer the slab and repair the pipe and put down new cement and new carpeting.

If I had to run PEX inside a wall I would remove the sheetrock and run it through the studs, header, or whatever and be sure to protect it from nails and screws much as one would do when running NM cable.

I have mice in my area and PEX would not last at all but become a convenient source of water for the rodents.