Insulating Your Basement

By Murray Anderson

Traditional masonry basements, whether they're poured concrete, concrete blocks or even stone have very little insulating value, so uninsulated basement walls will account for a substantial amount of heat loss, in some case it's estimated up to 20%). So, you can quickly see why adding insulation to your basement walls (whether you want to finish them or not), will help make your basement warmer and the floors above more comfortable while saving you money on your heating bills.  Here's some ideas on insulating your basement walls.

Don't rush into it

• Although putting up insulation on bare wall may seem like a pretty simple project (and it is) take some time to before you start insulating and to check these things and plan the job.
• Look for any signs of structural damage like cracks or bulges in the wall.
• Look for any signs of water or moisture problems such as actual leaks, dampness on the walls, efflorescence on the concrete or blistering and bubbled paint.
• Any structural damage or moisture issues need to be fixed before you insulate your basement, otherwise you are just covering up a problem that will come back to haunt a few years down the road.
• While you're checking out your basement walls also note any existing features that will make your insulating job more difficult and plan how to deal with them.  Just some examples are things like electrical panels, plumbing pipes or built in cupboards and shelves.
   

Insulating your basement walls

• What you plan to do with your insulated basement will help determine the type of insulation you choose. The most common choices for basement insulation are fiberglass bats, poly foam board or polyurethane spray foam insulation.
   

Unfinished basements

• Spray foam makes an ideal choice for rock or rubble foundations. It has a high R-value and it expands to fill tiny nooks and cracks. However, it's best applied by a trained professional and commonly needs to be covered with a fireproof covering.
• Rigid foam board is also a god choice for unfinished basements. It has a high R-value per inch and since this means it's thin, it doesn't require much supporting structure (framing). However, fire regulations commonly require foam boards be closed in with a fire proof covering like drywall, reducing their advantage over fiberglass bats in unfinished basements.
   

Finished basements

• Fiberglass bats make an excellent choice for finished basement walls. They're easy to work with, inexpensive and readily available.  The main drawback to fiberglass bats is the fibers can come loose and float around making them uncomfortable to work with. As a result, you should always wear long sleeves, a hat, eye protection, gloves and a dust make when working with fiberglass insulation to keep the fibers off your skin and out of your of your lungs.
• In a finished basement where the insulation will be covered with drywall foam boards can provide a space saving over fiberglass, however, foam boards are more expensive than fiberglass bats, perhaps offsetting their space saving.
• In any finished basement wall, before closing in the wall you need to have a vapor barrier that prevents moisture transfer between the warm room and the cold insulation behind the wall. A vapor barrier can be provided by 'faced' fiberglass bats or by covering the entire wall and the insulation with an unbroken sheet of 6-mil plastic. 

Murray Anderson is an experienced freelance writer over 500 articles published on the web as well as in print magazines and newspapers in both the United States and Canada. He writes on a wide range of topics and is a regular contributor to DoItYourself.com. He can be contacted at murand@lycos.com.