Pex Doesn't Stay in Thermofin U-fin

JudeNY

I have installed Thermofin U on ply sleepers over 1/2" Thermax on a slab. The pex is so loose in the U channel that it comes right out. Do you put adhesive in the channel before the tubing ? What kind ?

Bruce_6

I have seen that happen

we just crimped the U fin a little to hold the pex in place.

Mark Eatherton1

We use

silicone. Window sealant grade works fine.

ME

ALH

Thermofin

One thing that might be helpful in resolving the problem is to use a caliper and determine whether it's a Thermofin issue, a pex issue, or an installation issue. Is the plate getting stressed in a way that might spread the channel beyond 5/8 in? The pex should be a snap fit in both the C and U profiles. I would say adhesive is a last resort.

heatboy

I'll wager it's .................

the tube. I have installed both Wirsbo and Roth 1/2" PEX in UFin and it has to be driven into the channel. The outside diameter of the tube in question is undoubtedly not 5/8".

hb

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Contractor"

Doug_7

Go to: http://www.radiantengineering.com/Links/Finhomepg.html

JudeNY

Thanks all. The problem is the installer. The channel appeared so wide I was just pushing it in with my thumbs and unlike with the C channel, I couldn't see that it wasn't snapped in. Driving it in works. It is not as tight a fit in the U as in the C channel which is consistent with the samples Dale sent me last year.

heatboy, I need 2 more U fins - which I'm going to try to get sent directly from RE - to replace the 2 that someone walked off with - what could they possibly do with them? I used your posted pics as my model for how the installation between the joists should look and I'm pleased.

hr

Make sure

the channel is cleaned (vacumned out) before you install the tube. The tube should be a snug fit, but cold pex will fight you a bit. Use clips of some sort at the bends until you get the flooring down. Generally the loop ends are more prone to pop out and pull some more straight sections with it.

I'd stay away from any adhesives. Unless you smear it real thin with your finger they tend to lift the tube up and out of the "fit zone"

Also cover the installation as soon as possible dirt and saw dust will be ground into the edge of the channel and tend to start lifting the tube from the channel with constant foot traffic. Also you need to protect the tube from barrier damage and possible punctures from dropped tools, etc.

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Contractor"

JudeNY

Thanks hotrod. I was wondering about the bends. After I get the tubing in I am planning on covering it with heavy paper taped at the seams and lay down 1/4" ply until the finish wood floor goes in. Will that eliminate the need for clips ?

hr

Smart thinking

with the paper and ply. Yes that will keep the loop ends down and the whole assembly protected.

Look into 1/4" OSB (wafer board) or masonite, probably cheaper than 1/4" plywood.

Often times you can get a deal on sheets that have edge damage. The box stores cut great deals on damaged sheet goods Usually the say "make an offer."

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Contractor"

JudeNY

Thanks for the tips.