What open-cell foam does
Open-cell spray foam is a low-density polyurethane foam that expands roughly 100 times its liquid volume. It fills cracks, wire penetrations and odd framing that batts and blown material leave open, so the insulation and the air barrier go in together. Typical R-value is about R-3.5 to R-3.8 per inch.
Unvented attics
In Central Texas the most common use is spraying the underside of the roof deck to create a sealed, conditioned attic. Ductwork and the air handler then sit inside the thermal envelope instead of in a 140-degree attic. We spray to the depth the job and the local energy code call for, and apply an ignition or thermal barrier coating where code requires it.
Walls and sound
In walls and interior partitions, open-cell foam air-seals and absorbs sound well, which makes it a good fit for bedrooms, media rooms, offices and shared walls. It is vapor-open, so it lets assemblies dry, and it is trimmed flush with the studs before drywall.
HVAC after foam
Sealing an attic changes the load on the house. When a system is being replaced or resized, that work and the load calculation are done by a licensed HVAC contractor; we coordinate the foam schedule around it.
What the bid covers
- Masking and protection of windows, floors and finished areas
- Roof deck or wall cavity foam to specified depth
- Depth checks during application
- Trimming flush in walls before drywall
- Ignition or thermal barrier coating where required
- Cleanup and haul-off of trimmings
Questions about open-cell spray foam
Is open-cell foam a vapor barrier?
No. Open-cell foam is vapor-open. Where a vapor retarder is needed, such as in some below-grade or high-moisture locations, closed-cell foam is usually the better choice.
How long until we can go back in the house?
Plan to stay out of the work area during spraying and for the re-occupancy period on the product's data sheet, typically about 24 hours with ventilation. We will give you the time for the product being used.