Tips for Finishing Basements

Expert advice for a warm, dry and inviting space

First, Dry it Up If you have a damp or wet basement, you have to fix it before you start any finishing work. The good news is that most water problems can be remedied by two measures: grading the soil to slope away from the foundation and adding or repairing gutters and downspouts. If these steps don't work, you'll have to take more extreme measures like adding exterior drain tile and waterproofing the walls or adding interior drain tile that empties into a sump basket with a pump. Eliminating water problems is time consuming and expensive, but it's critical to prevent a moldy and ruined finished basement.

Measure Everything Know how much space you are working with. This is particularly important regarding height: Many local regulations on turning a basement into a livable area require that the basement be at least 7 feet tall, sometimes higher. Always consult local building codes.

Inspect Plumbing and Wiring You will probably need to add plumbing and wiring to your basement, including a separate bathroom. Check on existing systems to see what expansions and upgrades need to be done. Remember, you'll need a permit for this work.

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.

Install Proper Egress Windows One of the most important parts of those basement building codes we mentioned are egress windows, basement windows that both let in light and allow people to escape in case of an emergency. A live-in basement requires egress windows, so be prepared to expand existing windows and renovate your foundation to make room for them. We can help you install egress windows yourself.

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.

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.

Install Drainage Mats for a Warmer, Drier Floor Plastic drainage mats, or dimple mats, allow air to circulate under the flooring and provide a moisture barrier. They also provide an insulating layer of air that separates the floor from cold concrete, reducing the potential for moisture damage from condensation or water vapor migrating through the concrete.

Vary Your Lighting Choices

For the most interesting space, include several kinds of lighting in your plan. Start with good general illumination for times when you want a brightly lit room. Plan to add a dimmer switch to control the amount of light. Recessed can lights, ceiling fixtures and fluorescent “pillow” lights are a few types of general lighting. If you're worried about noise traveling upstairs, don't use recessed can lights.

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.

Hire a Pro to Design Your HVAC System Don't make the rookie DIY mistake of trying to heat your basement by cutting a hole in your main trunk line and screwing on a heat register. This will only create an imbalance in your entire heating system, and won't provide the heat where you need it. Money spent on proper design is a good investment. Hire a professional heating contractor to design your ductwork. If you would like to do the work yourself, look for a heating contractor who will provide the plan and possibly even the materials.

Frame Soffits With OSB Most basements have ducting or plumbing mounted below the joists that needs to be boxed in. The most common method is to build a wooden frame around them that can be covered with drywall. Here's a pro tip for building these soffits. Rather than frame the sides with 2x2s or some other lumber, simply cut strips of plywood or OSB (oriented strand board) for the sides.

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, like cork flooring for your basement. Interlocking cork flooring is easy to install, sustainably harvested and warm underfoot.

Consider Luxury Vinyl Tile Flooring A good basement flooring choice is luxury vinyl tile or planks. Luxury vinyl is waterproof and virtually indestructible. It's also easy to install and looks great. It's available in a plank form that looks like wood, and squares that look like tile. Floating luxury vinyl floors connect with self-adhesive tabs or interlocking edges. You'll find luxury vinyl at flooring stores, home centers and online.

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.