A Homeowners Guide to Finishing a Basement 

So let’s travel back in time to the 1950’s. The kids are bringing home friends and, well, mom needed to find a place for the kids to go. Someone figured out that the basement is already there, ready for action.  Add a little paneling and a couple of weekends work and maybe a pool table, and the kids would have a place to gather. With the possible addition of a six pack, the plan also worked for the adults and their friends. Welcome the basement game room to modern living.  

Click Here to Download "A Homeowners Guide to Finishing a Basement"

Sixty years later and the basement is still the cheapest place to add living space to a home. Today’s basements are “not your daddy’s game room” They are now often elaborate and expensive endeavors featuring wonderful products and materials that were science fiction in the 1950’s.

The bad news is that the words “moldy and basement” go together like the words “peanut & butter”. There are new building codes, energy saving requirements and changes in materials that have complicated the subject of finished basements.   

Today there are homes still under construction that are already growing fuzzy mold. Expensive does not mean “free from mold.” This year I have found two under construction homes over $750,000 in sales price that already had mold at an unhealthy level. Start with the normal moisture in building products and add that to “Energy Star” tight construction and you have the perfect petri dish.

As for older homes, buyers tend to think that a moldy and smelly basement will get better once they are living in the home. You can hear them say “the house smells like old people.” Guess what, after closing the only difference is that the new owner owns the odor and its causes, not the seller.             

As in most things, preparation is the most important place to start a project.

Look for water coming through the wall. White power, yellow stains or black areas on basement walls are the result of water penetration. Fix the cause. Water behind walls will result in mold, termites, carpenter ants and rot to materials.  It is also easier to locate and correct the water problem before walls and ceilings are installed.   

Test for moisture coming up from the floor. The simple trick is to securely duct tape the perimeter of an 18”X18” piece of clear plastic to the floor. Come back in 3 days. Look at the plastic. If water droplets have collected under the plastic, the water problem under the floor needs corrected before moving forward  

Test for radon and natural gas leaks before finishing the basement. In addition to making the basement a healthier environment, it will be easier and often less expensive to fix before the basement is finished.      

Move water and gas valves so that they can be used. They are installed for a purpose. You do not want to learn that purpose when water is running through a wall or ceiling.

Plan for all of the features you want in the room. Your plan should include any future changes that may happen in upper levels. Installing plumbing, wiring and heating for a future bath or other renovation will be easier when you have basement access. 

Check local codes. As one example, many codes and municipalities require the installation of a second method to exit the home from a finished basement. There are manufactured large window and window well assemblies that allow people another path to leave the basement. Many appraisers can’t add the value of a basement space as living space without that additional exit. Adding that feature can add thousands of dollars to the sales price. 

Avoid the Most Common Mistakes in Finishing Basements

Allow enough room around the hot water tank and furnace for both servicing and replacement. You will not like your plumber removing a section of wall to change your hot water tank.

Plan your rooms so that electrical panels are not located in clothes closets, bathrooms or stairwells.  That is an electrical code requirement.   

Allow for floor drains to be located where the traps can be filled with water. Sewer odor is a common problem if a trap dries out under a carpet.

Provide for comfortable heating, cooling and fresh air.  Call a professional for that part of the project. Most home improvement contractors and DIYers don’t have the experience or knowledge to make basements comfortable year around.  

Add enough lighting. Consider adding enough light fixtures to create a bright environment. Even if you call it a “man cave”, dark rooms are not pleasant and inviting.    

Solve moisture problems without adding interior French drains if possible. If an interior french drain is installed, seal the system.

Do not install sheet vinyl, not matter how cheap and easy it is to do. These floors trap moisture underneath the surface. The floor then turns gray with stains from moisture. 

Modern Tricks and Products for Better Basement Living

Material selection for the basement can make the difference between having an enjoyable family living area in the basement or a dreaded dark and smelly place.

Frame walls with steel studs instead of wood studs. It is not really so scary to use steel studs. They are easy to cut and screw together. They are better in basements because they are not a source of food for termites or mold. 

Do not install the new walls directly against the foundation. Allow an air space of an inch between your new walls and the foundation. That air space allows trapped condensate to vent out from behind walls.   

Use a wall finish such as fiberglass drywall. Traditional drywall, including MR (Moisture Resistant) board supports the growth of mold. Some of the fiberglass faced drywall products are DensArmor and Greenglass Board. 

Raise the wall finish and any wood trim about 3/8” up from the floor. This avoids the wicking of moisture up a wall if a leak occurs.  

Select a floor material that is resistance to water breakdown or mold.  Some examples would include carpet that is Olefin yarn based as opposed to other yarn systems. Avoid carpet pad. When you think about it, carpet pad is really a sponge that will hold dirt, odors and mold

Read the instructions on all flooring before purchasing. Yes, I know that reading directions is a tough task.  An example of why this is important is the popular composite or laminate flooring. Some of these materials specify “not for use in a below grade application.” Others require specialized underlayment or procedures for this use. Ceramic or solid vinyl flooring products such as Traffic Master are examples of good products for basements.  

When installing flooring, use adhesive suited for damp areas. Saving money on adhesives can be an expensive mistake

Cover plumbing pipes with foam insulation. Also insulate ductwork if you have air conditioning. Think of the glass of ice water on the table on the 4th of July. Covering pipes is like putting them in a Styrofoam cup instead of a sweating glass. You do not want dripping of pipes and ductwork.  

In the end, if a basement is not a comfortable place to go, it has little value. That is unless you want to grow mushrooms in your very own basement cave.