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Spray Foam Shrinkage and Gaps
in Tulsa, OK
Open-cell and closed-cell foam both need to be applied in layers of the right thickness. When a contractor goes too thick in one pass, the inside of the foam cures differently than the outside. Tulsa's attic temperatures in July and August push that problem further. The foam pulls away from the framing it was supposed to seal, and you end up with gaps you cannot see from the floor.
Quick Answer
Spray foam can shrink after it cures if it was applied too thick in one pass, mixed wrong, or put on in extreme heat. Tulsa attics can hit 140 degrees in July, and that heat stresses foam that was not applied correctly. Shrinkage leaves real gaps that let hot air in and conditioned air out. Call (539) 424-4019 to have those gaps found and sealed before another summer hits.
Telltale Signs
Warning Signs to Watch For
- Visible cracks or gaps between foam and wood framing in the attic or crawl space
- Rooms that used to be comfortable are drafty or hard to cool
- You can feel air movement around the top of interior walls
- Energy bills are higher than before the foam was installed
- Foam surface has small cracks running across it like dried mud
Root Causes
What Causes Spray Foam Shrinkage and Gaps?
Foam Applied Too Thick in One Pass
Closed-cell foam generates a lot of heat as it cures. If a contractor applies more than about 2 inches in one pass, the inside gets so hot it cures under stress and later contracts. In South Tulsa neighborhoods with steep rooflines and poorly ventilated attics, this problem shows up more often because the attic is already hot.
The Fix
Layered Reapplication Over Existing Foam
The gaps get filled in passes no thicker than what the product allows. Sometimes the shrunken foam can be built on top of. Other times the bad layer has to come off first.
Extreme Heat During or After Cure
Tulsa attics can reach 140 degrees in July. Foam applied in late spring when temperatures seem reasonable can then be baked during its first summer. Open-cell foam is more vulnerable to this. The foam loses volume slightly and pulls away from the edges where it meets the framing.
The Fix
Attic Ventilation Improvement and Gap Sealing
Improving attic ventilation reduces the peak temperature the foam is exposed to. Gaps are then filled with compatible foam in cooler conditions so they stay closed.
Wrong Foam Type for the Application
Open-cell foam is cheaper but not right for every spot. In Tulsa crawl spaces and rim joists, open-cell foam absorbs moisture from the ground and expands and contracts with humidity swings. That movement causes it to pull away from surfaces over time.
The Fix
Foam Type Replacement with Closed-Cell Foam
In moisture-exposed areas like crawl spaces, closed-cell foam is replaced over the open-cell material. Closed-cell foam does not absorb water and holds its shape through humidity changes.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Foam Applied Too Thick in One Pass | Extreme Heat During or After Cure | Wrong Foam Type for the Application |
|---|---|---|---|
| Gaps along roof deck in a steep-roofed attic | |||
| Shrinkage noticed after the first full summer | |||
| Foam pulling away in crawl space rim joist area | |||
| Uniform cracks across large foam surfaces | |||
| Foam damp to the touch in crawl space |
Free Inspection
Get a Diagnosis in Tulsa
An on-site inspection is the only way to confirm which cause applies to your property. Free, no obligation.
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