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Community and Q&A

ThermoCore Roof SIPs – 8″ Panels

jackofalltrades777 | Posted in Green Products and Materials on

Anyone here use or have any experience with the ThermoCore SIPs? They are based out of Indiana and have a 8″ polyurethane SIP ( I know about the blowing agents) with a R-50 value that I am considering using for my roof. Zone 4B

Some key points:

1 – I will be air sealing all interior panel joints with a T&G connection, caulk, gasket, and finally a peel & stick tape to ensure complete air tightness.

2 – I will use an ERV

3 – On the exterior I plan on putting a peel & stick butyl membrane that is vapor impermeable and then a standing seam metal roof.

If all these measures are done to ensure air tightness in a dry climate Zone 4B , I am hoping that I am safe from “sip rot”. The reason for NOT doing a cold roof is that it is a wildfire area and doing a cold roof would allow embers to enter between the OSB cold roof panel the the SIP. This would create a fire potential.

Any comments about ThermoCore and the above install approach would be appreciated….

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  1. wjrobinson | | #1

    Peter, why ask here? Call the company and get a list of users to visit and or discuss with.

    If you follow the manufacturer's assembly then they become liable not you so get your assembly approved by the manufacturer not GBA Q&A.

    As to opinion... I say you should be fine.

  2. Kevin_in_Denver | | #2

    The inside taped joint is the critical one. Use one of the European super sticky tapes WITH primer. (eg. SIGA)
    R50 is good but not great. If it were my house, I'd add a layer of polyiso on the inside.

  3. Expert Member
    Dana Dorsett | | #3

    Unless the manufacturer will stipulate that the polyurethane is blown with one of the low global warming potential(GWP) blowing agents (typically HFO-1234yf, under the trade names "Solstice" or "FEA-1100" which has a GWP less than 4x CO2) it is almost certainly blown with HFC245fa, which has a GWP of about 1000x CO2, and is the opposite of "green" from a life cycle environmental impact point of view.

    It's one thing to use HFC-blown polyurethane for air sealing, but as the primary insulation in even a code-min assembly it does more damage than it ever makes up for in reduced energy use damage.

    Find out what they're using for a blowing agent- try to convince them to move over to Solstice of FEA-1100, at which point they should ADVERTISE the fact that they only use low GWP blowing agents for their foam ( not merely ozone-safe goods, which is required anyway per the Montreal Protocol.)


    EPS-core SIPs don't have that issue, since EPS is blown with pentane, at a modest GWP of about 7x CO2.

  4. jackofalltrades777 | | #4


    I do plan on putting Roxul batts (R-10) on the underside of the ceiling, which will bump me to R-60.

  5. citorider | | #5

    Hi Peter
    did you go ahead with thermocore? How do you found them? I am thinking to use them and I would appreciate any feedback.

  6. jackofalltrades777 | | #6


    I have not started the build so I have no feedback as of yet. Hoping to hear from others who have used them.

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