GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Which spray foam manufacturer to choose from

kevinkeegan | Posted in GBA Pro Help on

I have two insulation Contractors and each one has their particular spray foam product they work with. One is using Thermoseal 500 open cell with an R Value of 3.7 and Thermoseal 1 closed cell with an R value of 7.2. The other Contractor is using Victory Polymers VPC -50 open cell with an R value of 4.1 and Victory VPC-CC Super yield with an R value of 6.9. The install price seems to be very close. I would like your opinion as to which product would be a better choice? Also is there any concern about spray foaming over electrical house wiring, in terms of the heat that is generated from the spray foam product.
Thank you, Kevin

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. mgensler | | #1

    I would ask for an independent lab test from them. My guess is these are numbers before it is fully cured. I specified the amount of spray foam in inches to try to avoid this and my contractor pulled out a report right before they started showing their foam was 7.2 or something. I told him it didn't matter, I still wanted the x inches I specified. His report was written by the manufacturer and I couldn't tell where they came up with the R value.

    Not sure about the wiring question. I have some wires encapsulated in foam and it has been an issue.

  2. Expert Member
    Michael Maines | | #2

    R-value testing is pretty specific, including aging for six months before testing. But sample size and environmental conditions while aging are flexible, so you could test the same exact foam two different ways and get two different results. Closed cell foam will lose R-value over time and will eventually reach R-5.6/in, the same as still air, once air displaces the blowing agents inside the tiny bubbles in the foam. Open cell foam maintains its R-value.

    For health and environmental reasons I only use foam when nothing else will work. But if you're set on using foam, if open cell meets your total R-value requirements and will not pose a moisture accumulation problem, it's a better bang for the buck--both "cost per R" and embodied carbon emissions per R.

    Both open cell and closed cell foam are created by exothermic reactions, with closed cell being more strongly exothermic and thus having a higher temperature that in theory could melt electrical cable. But spraying over cable is commonly done and I have never heard of an example of it causing problems. (I have heard many examples and seen a few myself where foam did not cure properly, resulting in expensive remediation, however.) If you want closed cell foam, the newer HFO-blown formulation has about 25% the global warming impact of older HFC formulations and does not get as hot while curing.

  3. oldbungalow | | #3

    We had spray foam done over wires it was not an issue.
    You have to be careful if you have CPVC pipes though, including the orange sprinkler kind. They should not foam those as it could lead to failure. PVC drains/vents are OK, they're quite thick and not under pressure.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |