How to Insulate Your Basement

A lot of homeowners remodel their basement to improve their home’s value. And the first step to any basement renovation is installing proper insulation. So it’s an important step to get right. 

Plus, proper insulation lets you control your basement’s temperature and humidity. That way, you could put another bedroom in the basement or make it an entire extra living unit of its own.

Insulating your basement will also help you save on heating costs in the winter and A/C costs in the summer. The insulation will prevent the inside temperature from escaping and the outside temperature from coming in. The US Department of Energy (DOE) shows that a finished basement can also save you up to $390 in electrical costs per year. 

Basement Insulation Prep

Before you start installing the insulation in your basement, you need to address any moisture first. The basement should be dry before you begin.

You’ll then want to make sure you can install the insulation at least 1 inch off the wall so you can create a drainage system at the bottom of the dead space. 

If it’s dry and you have the space you need, you’re ready to get your materials.

Basement Insulation Materials

You’ll need two main materials when doing a simple DIY basement insulation: foam sheets and spray foam. 

Foam sheets are large and rigid sheets of expanded polystyrene foam (XPS). They come in sizes up to 4 x 8 feet and are 0.5 to 2 inches thick. They can be cut with an ordinary wood saw and are relatively inexpensive at anywhere from 30 cents to 1 dollar per square foot. You’ll want to use these prior to framing the walls. 

Spray foam, aka spray polyurethane foam (SPF), is a sprayable plastic widely used for sealing cracks, gaps, and cavities in buildings. It’s shot with a special hose and gun and expands upon contact. After drying, you can trim the excess foam away to clean it up. Spray foam is best for when the walls have already been framed. It’s also good for irregular walls and those with many seams and joints. 

Installing the Basement Insulation

Before installing the foam sheets, measure out the walls you need to cover and then cut out panels into the sizes you need. 

Then add adhesive to the backsides of the foam sheets before lining them up against the wall. Once they are in place, nail them in. Cover any seams with tape and then fill the remaining holes with the expanding spray foam. 

Be sure to aim precisely with the spray foam. You don’t want to get it everywhere. Then cut off any of the excess foam that you don’t need once it’s dried.

Final Tips

Some other options for insulation material include mineral wool sheets or fiberglass made from sand. These can be more environmentally-friendly options, but they are also more expensive and may collect moisture more easily. 

For installing insulation the easy way, you’ll want to stick with the foam sheet and spray method above. And to make the insulation doubly strong, you can repeat the process to add an extra layer. 

Once you’re done with the insulation, you’re ready to move on to finishing the plumbing, electrical work, painting, and so forth. Whatever you do, hire professionals if you’re not trained or equipped to do the job yourself. In the long run, you’ll be glad you did.

And if you need more help with the basement insulation, it’s always good to get the help of an expert as well.