Is Foam Evil? A New Paradigm of Foam - Less is Best
"Is Foam Evil?" was the initial title of a panel discussion 475 participated in at NESEA's Building Energy 15 Conference - before it was renamed "Tiny Bubbles" (see Green Building Advisor's highlights toward the end of this article). Here at 475 High Performance Building Supply, we are famously anti-foam, with particular emphasis given to closed cell spray polyurethane foam (ccSPF). In our blog series Foam Fails, we've taken an extended look at the problems of foam insulation. We've even written A Declaration of Independence from Foam Plastic Insulation, that in the style of our Founding Fathers, makes the case against foam and the companies that push it. Each day we are reminded of the performance problems of foam, whether it's another building burning, or another failed blower door test.
Foam has real baggage in terms of health risks and performance challenges. Foam ingredients are toxic and highly sensitive to environmental conditions. If you spill enough of the Part A-MDI, the industry recommendation is to call the Superfund phone number. Installers should be using air supplied respirators and fire fighters are threatened with hydrogen cyanide combustion gases. If that wasn't enough, for the foam to cure properly, a dizzying array of criteria must be met on the construction site and evaluated by construction workers that often lack adequate training. If the mix is off and curing isn't complete, off-gassing can continue, potentially making the building uninhabitable. Good riddance.
We have other choices. For thermal insulation: use cellulose, mineral wool, wood fiberboard or fiberglass. For airsealing and vapor control: use membranes, sheathing, and tapes. Where there are viable alternatives to foam they should be pursued (and we love highlighting projects that do).
But despite all the negatives of foam - and despite all the available alternatives to foam - even we are willing to admit that foam isn't going away completely. And *gasp!* in a few instances it might actually be useful.
Therefore we aren't concerned with eliminating foam use outright, but instead we want to radically reduce its use. There is no reason to encase our buildings, our families and our co-workers in a foam-based enclosure any longer. We can remove 90% of the foam in construction very easily, and have a better building and environment as a result (see a recent example at Dartmouth College). What remains? Hopefully just foam in architectural components such as structural thermal breaks, mechanical equipment, and fenestration details. Less is best.
One architectural component that has gotten the right idea are Passive House windows and doors that use wood fiber insulation as a thermal break material and abandons the foam altogether. We like that.
The new paradigm is: Push toward foam-free construction with only very targeted and limited applications remaining.
Think of foam use like radiation treatment. Sure, radiation can be useful, but its recommended use is limited and targeted.