Crawl spaces. Even the name is unappealing. It conjures visions of darkness and creepy crawly things, and because of that the space under your home is one of its most neglected and misunderstood areas.
What it should bring to mind however is health, and while your home’s health can be gauged in the crawl space, what I’m referring to is your family’s health. As much as 20-40% of the air that enters the first floor of your home enters from the crawl space, and that will include any moisture, odors and mold that exists. If you have a rodent problem, the crawl space air is compromised by their waste.
All homes experience what is called the ‘stack affect’. Heat rises, and the overall flow of air in a home, especially in a two story home, is up. In addition, homes heated by fan-assisted warm air – think ducts and vents as opposed to electric baseboard units – are somewhat depressurized. Air has to come from somewhere to make up the pressure difference, and a large portion of it is getting drawn in from your crawl space through small openings around ductwork, gaps in the flooring, electrical wires, plumbing lines, etc.
So what can you do to keep unhealthy air from entering your home?
There really are two approaches. The first is to plug as many of the gaps, cracks and holes that exist in the crawl space ceiling with caulk, expanding foam, etc., and then make certain all the ductwork joints are sealed. This will reduce the amount of air that can enter your home from the crawl space.
The second addresses the actual quality of the air in the crawl space. This effort begins with maintaining as much ventilation as possible. Do not block the vents in an unadvisable attempt to keep the space warm. Keep the vents clear of vegetation, dirt, or anything else that can block airflow, but make certain the screen is in good condition to keep out rodents. Keep the dirt floor completely covered by a plastic vapor barrier, preferably with the seams taped. Eliminate any plumbing leaks. If you have problems with high ground water levels, have a sump pump professionally installed. If the entrance to the crawl space is outside, make certain the closure is sufficiently sealed to keep out rodents.
Finally, if your home is relatively new and has mechanical ventilation built into the heating system, use it. A large number of people do not know how to use this whole house ventilation and just shut it off thinking it unnecessary. It was installed to provide fresh air and to help keep your home healthy for your family. Since you should have your heating system serviced annually anyway, make a point of talking with your service technician about how the system is designed to provide fresh air.
If you take simple and logical steps to keep your crawl space healthy, you have also taken simple and logical steps to keep your family healthy and breathing clean fresh air.