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chefwong
02-24-2012, 03:39 PM
3/4 Pex sticking out of Sheetrock.
The RO for the hols is a good 1/4+ bigger than the OD of the PEX.

A baseboard will be mounted with the PEX right on the back of the baseboard.
Then hung on *cleats* at the same while -the pex- is pushed back into the cavity.
The baseboard will sit flush on the wall.

I cannot think of a way to insulate the hole once all said and done or during the process of installing...

Hackney plumbing
02-24-2012, 04:12 PM
Maybe some foam gasket. The kind thats sticky on one side. Cut it a tad bigger than the hole in the base and when the heater makes contact it should seal?

Dana
02-27-2012, 09:11 AM
If the water temp is low enough (probably is, if you're using PEX) a flexible 1- part "Window & Door (http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0830/0901b803808303cb.pdf?filepath=styrofoam/pdfs/noreg/179-07324.pdf&fromPage=GetDoc)" foam can be used during installation, since it will handle the expansion & contraction of the PEX with changing temp. Most of those "ever flexible" window & door foams are good to more than 200F after installation (Dow's product specifies 240F max.), and most PEX warranties stop at 180F.

chefwong
02-27-2012, 02:41 PM
I thought about the expanding foam....I have the Hilti gun setup with the foam ...
HOWEVER, the trick is getting the *material* in during or after the baseboard is hung

Note: Pex Stubbed out Wall
Cut Pex to a smaller stub out wall.
Hold 6' baseboard and install pex on both sides of the baseboard
Push baseboard+pex back flush to the wall and then hang it on the *cleats* that are on the wall
Baseboard is now flush - pex has moved into the wall by the mere presence of flushing the baseboard to the ball

Dana
02-27-2012, 03:02 PM
The stuff takes 30 minutes or more to cure to a non-tacky surface, and continues to expand. If you give it an ample shot on/around the PEX just before you pushed it in and hung the baseboard on the cleats it might end up gluing the baseboard to the wall, but it would make the air-tight seal as it expands.

dlarrivee
02-27-2012, 04:10 PM
Exactly.

Use the foam in a can but use it SPARINGLY, sort of like when they say to use a pea sized dollop of toothpaste.

Trust me, it WILL expand and fill the void, after the base is on.

Dana
02-28-2012, 12:28 PM
The window & door versions tend to be a much lower expansion ratio than the big-gap fillers, so being a bit more generous than a pea-ball is called for, especially since you'll likely lose half or more of it inside the wall cavity when you slide it in.