A poorly insulated building isn’t just an energy hog. The loss of
conditioned air frequently makes it an uncomfortable place to
live and work, not to mention the extra expense of heating it in
the winter and cooling it in the summer.
There are a plethora of insulation choices on the market to fit any structure, space type, or climate, but which is best for your building? The answer lies in your building’s layout.
The Basement and Other Below-Grade Spaces
Concrete floors don’t typically offer many insulation opportunities unless the building owner is willing to pay for a costly floor elevation, says Gordon Hart, consulting engineer for Artek Engineering.
Walls, however, are a different story. Rigid foam boards, for example, can be added to the interior basement walls, as can fiberglass batts. However, both of these routes require you to install wood studs and then add drywall, and you may have to account for basement windows or other needs because the retrofit makes the wall thicker.
“Usually, it’s better to insulate the basement walls because the basement has pipes in it and you don’t want them to freeze,” Hart explains. “If you’re on a concrete floor, there’s not a whole lot else you can do unless you want to elevate the floor and put in insulation boards, which is an expensive way to go.”
Above-ground floors offer many more opportunities to cut energy waste with proper insulation. Your choices here revolve around factors such as:
- R-value per inch of thickness
- Expected lifetime
- Ease of installation
- Your building’s envelope and construction type (which determine how much space you can fill with insulation)
To make the right decision for your project, put your priorities in order, says Brock Osborn, business development manager for reStore, the restoration arm of cladding manufacturer Sto Corp.
“Many times there will be a space limitation on how much insulation can be added and what the desired R-value would be,” Osborn explains. “Take into consideration terminations and junctures, such as how the insulation terminates into windows, doors, and fixtures.”
Narrow down the selection further by considering cost, how the insulation is installed, and how much disruption to normal operations your facility can tolerate. Rigid insulation, such as boards made of expanded polystyrene (EPS), extruded polystyrene (XPS), or polyisocyanurate, require you to affix the insulation either to the wall or the exterior and add a surface over it.
Flexible materials like spray foam or mineral wool only require a hole in the wall so you can spray into the cavity or the walls of an empty room, such as an attic. Use extra care when spraying foam into a wall cavity – if you can’t see what’s happening, you run the risk of over-pressurizing the wall as the foam expands, potentially warping the wall.
“Mineral wool has some clear advantages in certain areas when it relates to fire, which is why it’s commonly used in exterior rainscreen wall applications,” Osborn says. “XPS and polyisocyanurate tend to have higher R-values, so that sometimes factors into the insulation selection process, but EPS is usually the lowest cost. It’s not a magical formula – sometimes it just boils down to personal preference.”