Even though winter now appears to be over in the San Francisco Bay Area, we received so much rain over the past six months that many homeowners experienced water-intrusion problems for the first time. Most of the homes in the greater Bay Area are built on perimeter concrete foundations and have “crawl spaces” under the first-floor framing. Until recently, no measures were taken by builders to prevent naturally occurring groundwater from making its way under any nearby homes (and into the crawl spaces of these homes).
Once groundwater has entered the crawl space, it is very difficult to dry it out. When water is present in building material (or soil), it will start to move from the wet area to the dry area. So the moisture under the home will attempt to move into the living space above, and the more water that is present, the more likely that this transfer of moisture will be successful. In homes with hardwood flooring, it is common to see the “cupping” of the hardwood slats, this is a clear indication of moisture that has made its way from the crawl space, past the hardwood flooring, and into the living space above. And once this happens, this moisture will almost certainly result in the growth of mold spores, and a call to Bay Area Mold Pros!
There are several things that homeowners can do when they have groundwater in the crawl space of their home:
Consult a drainage expert. There are many contractors in the San Francisco area who specialize in drainage issues and the installation of French drains. These systems divert water around and away from a home, and they are very effective at addressing this problem. Sump pumps installed in crawl spaces can also be very effective at controlling this excess moisture.
Vapor barriers. Once the “standing water” issues have been addressed in the crawl space (through either a French drain or sump pump), a vapor barrier can be placed over the soil or concrete in the crawl space, and this will essentially prevent the moisture within the soil from making its way into the home above. There are numerous companies in both San Francisco and San Mateo Counties who specialize in this work.
Run a dehumidifier. Homes that are experiencing the transmission of moisture from a wet crawl space into the living space above will have elevated humidity. One of the best ways to control this humidity is by running dehumidifier machines in the most problematic rooms of the home.
So the bottom line is this…if you have groundwater that has made its way into your crawl space, you need to address it, and if you don’t, you’ll be calling Bay Area Mold Pros to inspect your home for mold…because you will have mold!