Basement Finished Space and Moisture

Several months ago I performed a construction progress inspection on a large expensive home under construction. The home was in the drywall finishing stage with a mother-in-law suite in the basement, or as you Realtors and Builders prefer "lower level" (Be advised if its more than 50% below grade, it's a basement!). As we walked through the home, a large walk-in closet was observed off of the basement bedroom. The closet had no window and was fully below grade adjacent to an unfinished basement area, which was mostly below grade with no window. The closet was finished with drywall, had a door from the bedroom and the only access door into the unfinished below grade basement area. Neither area was conditioned (no heating or cooling) or ventilated.

Adding conditioning to both the closet and unfinished basement area was recommended to control moisture.

Upon my return to the almost finished home a week prior to closing, opened the same closet door and observed the drywall about half way up the wall, baseboards and doors covered with surface mildew and mold. Just the spot your mother-in-law and mine would desire to store her clothes and a perfect way to make her very sick. Most mother-in-laws are hard enough to live with, without being sick in smelly molded clothes. As happens more than I prefer to acknowledge, my recommendation had been ignored and now the consequences would have to be dealt with.

There was no problem the first time I visited the home, everything was functioning as intended and nothing was in need of immediate repair. Why then did I make my recommendation? How did I know there would be a problem later?

Construction of a home involves a lot of water. Almost every major component contains water or has to have water added for installation. The home is open to weather during construction and much of the material absorbs moisture during construction. This moisture requires a considerable time to leave the material, sometimes years. A below grade basement has the highest concentration of water and dries the slowest. The soil below and outside is wet and moisture is added continually before and after construction. The concrete floors and block walls are wet and in many cases one of the last things a builder does is wash down the floors and walls with more water. Take this wet space, enclose it with a drywall room, add doors, no light, no ventilation and what do you have? A perfect cave for growing mushrooms, not to mention mold and mildew.

The only way to change this condition is to add ventilation and conditioning to dissipate the moisture and dry out the space. No mater how dry a basement appears, it needs to dry out. Trap this moisture and you are asking for trouble. The concrete and masonry is giving up moisture, which has nowhere to go. The drywall, base and doors are dry, seeking moisture. The room (cave) becomes increasingly damp and things that love dark damp places begin to grow. Add carpet, clothes and shoes and you gain an expensive cleaning bill, if it's possible to clean them at all.

You should be prepared to advise your clients of such issues. Had this occurred after the home was occupied, who's phone do you think is going to ring? If it's mine, at least I will be able to say: "Told you so! Did you do what I said?" What will you and the builder have to say?

Do you want to buy this closet? It meets building code requirements, just ask the builder and he will tell you so.

Do you think home inspectors should be limited to "not functioning as intended and in need of immediate repair"?

Do you think new homes should be limited to meeting minimum code requirements?

Is adequate, proper, clean, functional space important to your buyer and to you?