GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X 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

Air Sealing

Countrygirl | Posted in Energy Efficiency and Durability on

Is it practical to expect Demilec Heatlok HFO Summer Closed-cell Foam to create an airtight house when istalled correctly.  Providing all cracks and joints to the exposed outside wall are also sealed with sprayfoam (cans).  We are striving to get below 2.0 with our blower door test and our installer is telling us that it is not possible. Which we undestand to be incorrect.
a rapid response would be appriciated as we are 2 months in the insulation phase and we have had all surfaces sprayed with 2-5.5″ and we need to move onto the next step in getting our house built.
Thank you!

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. walta100 | | #1

    My guess is you will not have a problem getting a blower door test under 2.0ACH50 but your insulation contractor can not promise you that because so many places air can leak are outside of his control and other workmen may well make holes in his work.


  2. Expert Member
    Michael Maines | | #2

    Spray foam is good at making the middle of the wall airtight, but so does the structural sheathing if you tape the seams. Canned foam will fill small gaps but tape or sealant usually does a better job. Using tapes, with little to no foam, my projects routinely reach 1.0 ACH50, and have been as low as 0.12 ACH50.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |