Expandable spray foam and plates

Mike Lampkin_2

With plates and pex under floor,what's your thoughts on
using an expandable spray foam to insulate the plates and
tubing, rather than insulating with batts? I was thinking
of spraying about 2 inches of foam right over the plates
and tubing in the joist cavity. The contractor is using
the spray foam to insulate many other areas of the house
and since it is all new construction, it would be very
easy to do this. Thanks for now.

hr

I have

done two jobs now with isoneyne foam sprayed against the transfer plates. Both were open web truss floor framing, and this was the best approch to insulate. We used 3-4" thickness, 6" on the rim joist areas.

Check with the manufacture for temperature ratings, although with plates you should be fine. I have seen spray foam on near boiler, 180° pipes, not a pretty sight

hot rod

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Mike Lampkin_2

Plate temperature


Hi Hot Rod....thanks very much for the reply. At design
temperature, the maximum water temperature should not be
more than 130 degrees (F) at the plates. I'll check the
temperature rating for the spray foam. Regards.

Rudy

I would like to see.....

the infrareds on THAT setup. 4" sprayed right on the conduction plates? As always hr you continually raise the bar. Might it actually add to striping?

hr

I wondered about stripping also

once the wonderboard and tile was put over the top the floor temperature evens out nicely. With this open web truss 16"oc the space between the 2X4 top cords (3-1/2" wide) had the plates pretty close together anyways.

I just couldn't see a good way to use fiberglass batts in these trusses. Also the foam was sprayed over the top cord insulating this portion from any down loss, as it connects to the heated sub floor.

We also had to work around a lot of HVAC duct work, the spray foam was a lifesaver in that respect also.

hot rod

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