Adding Basement Insulation

by Murray Anderson

Playing with the idea of finishing your basement but not certain you want to take on the job or can afford to hire a contractor to do it for you? Even if you never decide you want to take the step and finish your basement, you would be well advised to consider upgrading your basement insulation. Adding basement insulation will help make your living area more comfortable, will save you money on your energy bills and is the first step towards maybe finishing your basement. If you're wondering about adding insulation to your basement, here's some things to consider.

First thing first, make sure your basement is dry

Before doing any insulating of your basement walls, you need to be sure your basement doesn’t have any moisture problems. Adding insulation to a basement that is moist or continuously damp is a waste of time and money.
Moisture can get into your basement through cracks or openings in the foundation so any visible openings need to be repaired..
As well, moisture can also seep through the walls themselves. Making sure the ground around your foundations is sloping away from your foundation and your downspouts and gutters are emptying well away from your foundation will ensure moisture from above isn’t getting into the ground around your foundation where it will sit against the walls and eventually work its way inside.

Insulating Basement Walls

Installing foam sheet insulation

Commonly made for polystyrene or polyurethane these large sheets (4’ X 8’) can be applied directly to foundation walls or cut to size and fit into openings in stud walls.
Foam insulation provides good insulation (R-values from approximately 5 to 8 per inch of thickness), and also have the advantages of being impervious to insects and moisture.
Its important to cover all the seams between the sheets with moisture proof tape to prevent any air or water movement.
Most building codes require foam sheets be covered with a fire resistant barrier such as ½” of drywall which can be installed over the insulation by installing furring strips to the insulation, followed by the drywall.

Install blanket or bat fiberglass insulation

Installing fiberglass bats requires building a stud wall around the exterior of the basement and filling the gaps with fiberglass insulation.
The openings in the stud wall or the air space behind it allows for the installation of wiring or plumbing for the new living space before adding the insulation. After the insulation is installed the wall can be covered with drywall.
Because of it's adaptability and versatility this insulation method is commonly used when home owners are planning to develop their basement for additional living space.
Similar to foam insulation, building codes require the fiberglass bats to be covered with a vapor barrier (often a 6 mil plastic sheet stapled to the studs with the seams overlapped then covered with moisture proof tape), before installing the drywall and closing in the wall.