Installing PEX in attic ( non heated space )

[KSHandyMan]

A plumber I called said that in order to provide water to a second shower head in a shower I'm installing I could run a piece of 1/2" PEX above the shower through the attic. He said that since shower heads always drain and there is no standing water in the line it would be OK even in a non-heated space. Does this sound right to you?

 

[Lee Polowczuk]

I ran pex up to my non-heated attic for a toilet water line... i will be doing two more lines for a sink.... and maybe a shower down the road.

 

[Sponsor]

 

[KSHandyMan]

Did you drill holes in the joist or did you just run it over the tops of the joists and then put some insulation over the top of it?

 

[Rancher]

He said that since shower heads always drain and there is no standing water in the line it would be OK even in a non-heated space. Does this sound right to you?

Nope, it doesn't. Is this run of PEX from the shower control valve up an into the attic and back down to the nozzle, or is this the water supply to the control valve. If it's the latter it will always have water in it.

Rancher

 

[Jadnashua]

It depends on the valve...if it is a dedicated shower, the line could retain water in the feed side. After the curve to come down, it would drain, and maybe siphon a little of the rest, but not much since there is no air inlet to allow it to flow. If it is fed from say a tub divertor spout, then yes, it should drain after use in both directions - out from the top, and in the supply internal out the spout.

 

[Lee Polowczuk]

Did you drill holes in the joist or did you just run it over the tops of the joists and then put some insulation over the top of it?

I ran my pex vertically up the wall from the basement. i would avoid drill through joists if you can.

 

[KSHandyMan]

Nope, it doesn't. Is this run of PEX from the shower control valve up an into the attic and back down to the nozzle, or is this the water supply to the control valve. If it's the latter it will always have water in it.

Rancher

This attic line going to the second shower head comes directly from the shower hub so when the shower valve is off, there is no water pressure in the line. But, there is no bath valve below so there is a chance that while most of the water would drain out of the line, there may be a little water sitting in the line just above the valve. It wouldn't be pressurized but the line may not be completely free of water.

Here's a picture of what I'm talking about. I called the local Building Codes people and they said it should "probably" work. I love getting that kind of definitive advice....

 

[Rancher]

Well if it does freeze, the worst that will probably happen is that you won't get water out of that nozzle.

Rancher

 

[Jadnashua]

Pex is fairly springy, and unless you anchor it, will form an arch. Depending on which way it comes off of the roll and is installed, especially if you anchor it, youwill likely have some low spots which will hold water. You could end up having half of the pipe full of water. They do make corner supports that allow you to get a tighter bend in a nice semi-circle. If you ran it up a little, then ran it down in a fairly straight line to the shower head, plus, if you did this so it was burried in the insulation, nearly all of the water would likely run out. Keep in mind though, that it will potentially act like the proverbial straw with your finger over the end - you may not get much to flow out regardless of the slope and care you use