THE INSIDE SCOOP
GREEN BUILDER RECOMMENDS
The best insulating choice is the one that respects your home’s design and orientation—along with your budget. For small retrofit jobs, pre-cut fiber glass batts are a quick and easy solution. To insulate an entire wood-framed home you can combine systems. For example, you might insulate the basement with rigid foam board, spray wet pack cellulose into the above-grade walls, and apply a hybrid spray-foam and fiber glass system to the cathedral ceiling. If you want to increase energy savings even further (and remove the roof ridge vent), fill the rafter cavities of the roof with expanding foam.
RIGID FOAM INSULATION
> High R-value per inch
> Seals against air infiltration
> Good solution for basement walls
> Some brands may shrink over time
> Producing synthetic foam is a resource-intensive process
RIGID FOAM WATER RESISTIVE
You may have seen contractors in your area putting green or blue insulation right over the wood siding of an old house. Chances are they’re applying extruded expanded polystyrene (XEPS) or polyisocyanurate closed cell foam. Both products are dense and durable. Some building experts suggest that foam used this way can an act as water resistive barriers (WRBs) negating the need for housewrap, but we recommend playing it safe and using housewrap as well. Rigid foam is also an excellent choice for insulating basement walls.
MINERAL WOOL NOTHING TO BURN
Although mineral wool looks like fiber glass, it’s made from basalt rock and slag, not glass. The resulting product, either batts or loose fill, is non-flammable, requiring no chemical flame retardants. As a result, off gassing emissions tend to be low. Mineral wool includes high levels of post-industrial recycled content waste (up to 90%), reducing the environmental impact of its production.
> Fire resistant without chemical additives
> High in recycled content
> Requires careful installation
> May need an additional air infiltration barrier
ECOBATT FROM KNAU
This fiber glass insulation has an unusual brownish color, in part because the manufacturer wants to highlight the fact that it does not use the usual petroleum-based chemicals found in most fiber glass. Instead, Knauf has replaced the usual phenol, formaldehyde, acrylics, and dyes with bio-based binders. As a result, the environmental impacts of creating EcoBatt’s binder agent have been reduced by as much as 70%. www.ecobatt.us
Icynene’s most eco-friendly brand of spray foam includes 12.6% recycled plastic in the mix. The product uses water based blowing agents and no ozone-depleting HFCs or PBDEs (fire retardants). www.icynene.com