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Air-Sealing Stair Treads from Crawlspace?

ehiker | Posted in Energy Efficiency and Durability on

I have a short staircase(4 treads) that need air sealing from the crawlspace behind it. Any preferred methods? I did insulate them as best I could 15 years ago with fiberglass and straps. Now want to air seal. I do have access to back side via the crawlspace. Thanks!

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  1. mgensler | | #1

    We just did this for a house on piers over a garage. We used closed cell spray foam on the steps and it worked great.

    1. ehiker | | #2

      This would be ideal but the job is so small for this to be cost effective!

      1. jadziedzic | | #3

        You can purchase a Touch 'n Foam 15 board foot or Froth-Pak 12 board foot 2-part DIY spray foam setup for around $50 (Amazon has a 2-pack of the Froth-Pak 12 kit for $98). I used a couple of these kits a while back to spray foam around some HVAC boots next to the rim joist in the basement. It wasn't terribly difficult, and if your goal doesn't include "professional appearance" one of these kits should do the trick for you. Add another $50 for a decent respirator since you'll be working in a tight space.

        1. ehiker | | #4


          Is this better than can of foam from HD (great stuff, tite foam, etc.)?

          1. jadziedzic | | #5

            For your intended usage I think I think you'd have much better results using the 2-part DIY system like Froth-Pak. The cans of foam dispense through a straw, and you'll have to try to spread the dispensed foam with some sort of tool (putty knife) while it is undergoing curing: messy at best, and probably poor coverage, and possibly an undesired impact to curing.

            In contrast the Froth-Pak system uses a spray nozzle which makes it a lot easier to get an even coat and get into every corner. You'd probably spend much less time and achieve a better result with the 2-part DIY spray system.

  2. ehiker | | #6

    Thank you! May try the spray can first and see if it will expand enough to air seal the seams between treads from the back. If not the froth pak is next.

    Does the froth pak foam allow for expansion/contraction with the seasons?

  3. the74impala | | #7

    Thats another reason some people avoid the spray. With extremes in temp changes, it can pull away.

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