Pro's Pick: RetroFoam Insulation

Dennis Gehman

President, Gehman Design Remodeling 

Harleysville, Pa.

RetroFoam is a nonadhesive, non-expanding polymer foam insulation. It contains no solvents, petrochemicals, or CFCs, so my crew isn’t exposed to toxic fumes. It’s also biodegradable, so we can take excess to the landfill. 

The foam is perfect for wood-frame walls. It’s blown in place through holes drilled through the sheathing behind the siding, or through the drywall. Tiny air bubbles in the foam create an R-value of 4.5 per inch, or up to R-16 for a 2x4 wall. 

We had tried other loose-fill blown insulations, but since they tended to hang up on wiring, pipes, and any obstruction, doing a thorough insulation job always meant removing the old drywall, installing batts, then hanging new drywall. No more. Because RetroFoam is non-expanding and blown at 80 pounds of air pressure, it flows into nooks and crannies and will even compress existing insulation and fill around it. The result is a well-insulated wall with an airtight seal.

This flowability makes it a real problem-solver. In my area there are lots of old, uninsulated brick homes with drywall over 1x3 furring. RetroFoam easily fills the gaps created by the furring, and homeowners tell us they feel noticeably more comfortable.

The foam does come with a few caveats. It’s more expensive than batts and, if using it in new walls, it needs to dry for a few days before you apply mud and paint.