Seal the Rim Joists
Uninsulated rim joists are huge energy losers. Now's the time to insulate and seal your rim joists. One option is to seal the rim joists with rigid insulation cut to fit. We recommend a minimum of 2-in.-thick extruded polystyrene, but check your local codes to see what's required. If you have a table saw, use it to cut strips equal to the depth of your joists. Then use a fine-tooth handsaw, utility knife or miter saw to cut the strips to length. Fill small gaps with caulk, and larger ones with expanding spray foam from a can.

Insulate Walls
Insulate exterior walls to prevent condensation. In cold climates, wall insulation in the basement also saves energy and reduces your heating bill. But don't cover the walls with insulation if water is leaking in from outside; you'll just create a potential mold problem.

Waterproof the Walls
Waterproofing materials that go on like paint fill the pores in the concrete or masonry walls and prevent water from leaking in. To be effective, these coatings must be applied to bare concrete or masonry walls. Start by removing loose material with a wire brush. Then clean off any white powdery “efflorescence” with masonry cleaner. Follow the safety and application instructions carefully. A common mistake when using masonry waterproofing products is to spread them too thin. The goal is to fill every pinhole to create a continuous waterproofing membrane. Brush the coating in all directions to completely fill every pinhole. Add a second coat after the first dries.

Warm Up Cold Floors With Heating Cables
You can warm up your basement floor with electric heating cables or mats. This type of heat doesn't warm the room much, but it makes floors much more comfortable. The downside is that heating cables are expensive to install and expensive to run. You can buy a loose cable system or mats with the cable attached. Loose cables are more work to install but cost less than mats. The more area you cover with cables or mats, the lower the cost per square foot.

Cork Makes a Great Basement Floor Covering
Choosing material for a basement floor is tricky. Carpet is warm and soft but susceptible to moisture damage. Tile is good for areas that might get wet, but it's hard and cold underfoot. Still, there are a few choices that strike a good compromise. Interlocking cork flooring is easy to install, sustainably harvested and warm underfoot.

Tips for a Quieter Ceiling
To quiet footsteps from the floor above, consider adding fiberglass batts to the joist spaces. You can add a 3-1/2-in. layer, or better yet, fill the joist spaces with fiberglass. For even more noise reduction, isolate the ceiling drywall from the joists with resilient channels. Screw the channels to the joists, spacing them 12 or 16 in. apart (ask your building inspector what's required). Then screw the drywall to the channels, being careful not to drive screws into the joists. This creates a “floating ceiling” that reduces sound transmission. You may have to visit a drywall supplier to find resilient channels.

Seal Around Pipes and Wires
Seal small cracks around pipes and wires with special “red” high-temperature silicone caulk. Fill larger openings with flame-resistant expanding foam. Close openings around chimney flues or other large openings by nailing sheet metal over them and sealing the edges with caulk. Sealing between the basement and upstairs will help prevent the spread of fire from the basement to upstairs. It will also save energy and prevent sound transfer from the basement to the upstairs.