My Crawl Space... But I Never Go Down There, So Why Should I care?

Many homeowners know their crawl space is nasty, so they never go down there. I don't blame them. In fact, I've never seen a dirt crawl space where I crawled in and said, 'heyyyy, this is okay'. It's always bad. Often really bad. 

Homeowners know it and don't go down into their crawl space unless they absolutely have to. They shut it out of their 'often visited places in my house' list, and shut it out of their mind, like it doesn't exist. Hey, if I don't go down there, what do I care? Right? Wrong. Way wrong.

If you care about your home rotting, mold, alllergies, asthma, then you care about your crawl space.

If you care about the comfort of your home, cold floors,mdrafts, and how your home smells, then you care about your crawl space.

If you care how long the paint lasts on your house, about doors and windows sticking, about hardwood floors buckling, and about carpets going moldy then you care about your crawl space.

If you care about your resale value, then you care about your crawl space.

The house is a building. It operates as a system. You can't have one part of the building that is sick and another part that is healthy. You can't rationalize that since you never go in the crawl space you aren't affected by it. Why? Simple Air mixing. 

Crawl Space Air Is Bad.
It is damp. It is cold if it's winter. It is full of mold spores. It smells. And this crawl space air is in your building envelope. It gets upstairs in one of two ways:

1. Stack Effect: It creates an airflow in your home from bottom to top. So air from the basement is drawn upwards into the first floor, and then to the second floor. Of course, it dilutes with other air in your home, but building scientists say that up to 50% of the air you breathe on the first floor is air that came through your crawl space. If you have hot air heating with ductwork, the air mixes even more thoroughly throughout the house. 

2. HVAC system through your ducts. 

You are breathing it. In fact, we know that 1/3 to 1/2 of the air that you breathe on the first floor of your house came through your crawl space. And this goes for basements, too, for people who have them. 

This fact has been proven by studies. If someone sprays paint inside your crawlspace, do you think you'd smell the spray paint upstairs? Of course you would.

Radon gas is naturally occurring radioactive gas that comes from the ground. For many years, we have known that if you measure the radon levels in your basement or crawl space, and then measure upstairs, you will have about 1/3 the amount upstairs. Since radon only comes from the ground, this demonstrates how air moves in a house- from bottom to top. 

You Breathe Crawl Space Air - Like it or Not

As warm air rises in a home it leaks out out of the upper levels. New air must enter to replace the air that escaped. In fact, in a tight home about half of the air escapes each hour out of the upper levels. This creates a suction at the lower levels to draw in replacement air. In older leaky homes, the air exchange rate can be as high as two air exchanges per hour. 

Therefore, whatever is in your crawl space air is in your house and affecting you, whether you spend any time in the crawl space or not. If there is high humidity downstairs, there is higher humidity upstairs than there would be otherwise. If there is mold in the crawl space, there are mold spores upstairs. If there are damp odors in your crawlspace- you get the idea. 


- Excerpt taken from Crawl Space Science by Lawerence Janesky.