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Boards, Batts, and Spray Insulation Basics
There are so many choices in insulation; before we can even start to look at the different materials, one should understand the strengths and weaknesses of the different types.
Loose Fill Insulation
Used in attics, poured in. Includes fiberglass, cellulose and denim.
Why we like it
Cheap and effective, can be poured to any desired depth
What we worry about
It is loose; it can therefore be inhaled. People used to use vermiculite, related to asbestos; glass fiber is thought by some to be dangerous.
Eco-factor of Loose Fill Insulation
It can be added easily, a quick and cheap way to get additional insulation.
Batt Insulation
Designed for use in wood frame construction, between studs and joists. Includes fiberglass, cellulose and denim.
Why we like it
Easy to install; held up by friction between the studs and joists.
What we worry about
Thermal leaks. It is going into the same spaces as electric wiring and outlets, and often is not fitted tightly. It can settle, causing cold spots at the top of the joists. Moisture can go through it, so a good vapour and air barrier is a must.
Eco-factor of Batt Insulation
As a form of insulation, it is probably the least effective at getting a really good seal.
Board Insulation
Used usually on the exterior of houses, often added as exterior sheathing to eliminate any thermal bridges through the studs and compensate a bit for the leaks through the batt insulation. Also used on the exterior of basements. Includes styrofoam, generic expanded polystyrene, fiberglass board.
Why we like it
It provides a complete seal, compensating for the flaws inherent in the batts in the studs.
What we worry about
Flammable and gives off toxic fumes. If used in interiors it must be covered with drywall. Styrofoam and expanded polystyrene are made from fossil fuels.
Eco-factor of Board Insulation
High R value per inch of thickness.
Sprayed Insulation
Sprayed in place by trained installers. Includes polyurethanes, soy foams, icynene and more.
Why we like it
Tight seal; it adheres to the studs, doesn't settle, usually is closed-cell (little sealed air bubbles) minimizing air and vapour transmission. Some are good for retrofits.
What we worry about
More expensive. Some are petroleum product based and give off toxic byproducts in fire.
Eco-factor of Sprayed Insulation
Gives the tightest seal, has high insulation value per inch, probably the greenest insulation from an efficiency point of view, and some are the greenest from a material content point of view.
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Green Your Home for Winter: Add Attic Insulation
Green DIY Projects: Build & Repair
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7 Great Ways to Insulate Your Windows
