Finishing Basements

Finishing our basement can increase the living space in our home at a fraction of the cost of constructing a new addition. Structurally, the floor, walls and ceiling are already in place - so it is just a matter of finishing them to make them look nice.

However, the first concern before finishing our basement is keeping it dry. It means protecting our basement not only from flooding, but from water vapor as well. A wet, or even just damp basement, is unsuitable for finishing. Moisture will get into the building materials and cause mold, mildew, rot, bad smells, and damage to floor coverings, furniture, and personal items.

The only way we can approach basement finishing is to treat it like a normal house that happens to have an exterior wall of concrete. We build regular 2 x 4 walls and tip them into place. The exception is that we use treated 2 x 4's for the bottom plate because any wood in contact with concrete has a high risk of rotting.

But before we install the wood framed walls we make sure that any moisture problems are fixed. Normally, we do this by acid-washing the walls with muriatic acid and water. Rinse, dry, and apply a premium basement paint. A good oil-based basement paint that contains a lot of cement in it is needed. We can glue sheets of polyethylene plastic to the walls to deter moisture from wicking through the concrete.

After the walls are framed, we approach wiring as usual. Plumbing is pretty normal except that some concrete cutting may need to be done to get the drains below the floor. We can just use a 7" diamond blade on a circular saw, which cuts about 2/3 of the way through a 4" slab. We can bust up the cut out by whacking it with a sledgehammer. A cold chisel helps too, while Wearing eye protection!

Once the utilities are over, we can insulate as usual with fiberglass, and install a wallboard material. On my first house I used 3/8" T1-11 rough-sawn plywood, with the 4" groove spacing. It's expensive but durable. However, Moisture Resistant drywall (the green stuff, used for bathrooms) can work well. It can also tolerate some minor flooding and is finished just like ordinary drywall.

We can use carpeting on the floor, but there is a good chance we will have a mildew problem just from lack of air circulation. Sheet vinyl might be better. An oil-based concrete paint with some throw rugs works well. Just keep the rugs away from the corners where the mildew lurks.

For the ceiling, many people choose suspended ceiling tiles. The 2 x 2' tiles look much better than the less expensive 2x4' tiles. For low ceilings there is now a tile that clips onto the track rather than laying on top. This means that we don't need to waste a lot of valuable headroom for the dead space above the tiles. Most ceiling tiles require perhaps 6 inches of space above the track to allow the tile to be manipulated into position. This is wasted space, space that is normally in short supply in base -ments. Home Depot is selling some sort of newfangled tiles that clip in place from below, but I haven't even stopped to look at them.

There is also this radon inert gas issue. This does not chemically react with anything, but it is radioactive. Some people claim that radon might cause thousands of cases of lung cancer every year. Or maybe it is just hysteria. Radon seeps out of the soil in some areas and gets carried away by the winds. They say that radon can build up in basements. A good ventilation can solve all such problems. Panasonic Whisper Lite fans are made to left running continuously and are very quiet. Anyway, there are radon test kits/device available. It's nothing to be alarmed about, just something to be aware of.

The moisture control problems are the biggest concern. Any short cuts that you take here are probably going to come back to haunt you, either as humid basement air, mildew/odor problems, paint peeling, rotting wood, or water damage to items stored in the basement. There is no reason why a reasonably modern house with a poured concrete or cinder block basement can't have living conditions equal to that of other rooms upstairs.