PEX and spray polyurethane foam

Weezbo

if you are using foam insulation as a means to stop air leaks or reduce the cost of the transmission of BTU's within living areas .

bang bang heat S/R systems will express the thermal expansion in the form of somewhat irritating Noise.

one simple means to reduce that is to have the leads to the baseboard emitters wrapped in poly sheathing ,the other is reduction of water temps...still that is not always the right answer..another concern would be the "Invincible to physics " concept.

when it is summer or what i call the "Grand Illusion " (of Winter) sometimes , people tend to forget the power of illusion that they are operating under... pipes placed on outside walls with no insulation other than the OSB and Vinyl siding with some foam sprayed over the tubing at rims and box beams, will likely Wake up from that enraptured stupor the first available inappropriate time next winter :)

Robert Jordan

PEX and spray polyurethane foam

Does anyone know if spray foam damages PEX? Uponor says they are testing but haven't had any reports of failure. Watts says any petroleum based product will damage PEX. Don't think there is any petroleum present once the foam has reacted though. However, someone told me that someone he knew had a problem.

Also, in an underfloor application with transfer plates, Uponor suggests putting poly up to keep the foam out and affecting the heat transfer (seems like a good idea), but said an air gap wasn't important or reflective foil would be any benefit. Watts, on the other hand, said to keep an air gap of 2 to 4 inches and have a reflective barrier. I am skeptical of the need for the air gap and the reflective foil or bubble wrap.

Steve Ebels_3

No problems here

We use an insulating contractor to directly apply urethane foam over pex in underground applications. The insulating company told me that they have been doing this for years, as in 15 or so, with no reported problems at all.