Understand the underside of crawl space moisture
Other Columnists
I live in a split-level home on the South Shore. The front
entrance door is on a slab, and the first floor has a living room, dining room
and kitchen over a crawl space. My problem is the foyer inside the front
entrance. The floor is ceramic tile, and the den to the right has a carpeted
floor. To the left of the ceramic floor is an office with a vinyl floor. The
tile floor collects large amounts of condensation during humid weather. It has
actually puddled in areas, even when there is cross ventilation from the open
front and rear sliding door in the kitchen. There is a dehumidifier in the
crawl space and ceiling fans in the office and living room.
I am thinking about putting a floating floor, like those manufactured by
Pergo, over the tile. Would this reduce the level of condensation? The den and
office floors do not seem to have the same condensation problem as the tile.
V. Lehane, Oakdale
The real problem seems to be the moisture buildup in your crawl space. Why
not tackle that situation instead of putting in new flooring? Colder floors,
like tile, will often develop more visible condensation. Your other flooring is
more porous and is probably absorbing more of the condensation. But moisture
still is entering your home via the crawl space. To control moisture, a vapor
retarder made from polyethylene or heavy plastic sheeting should be spread over
the soil in the crawl space. Ventilation also should be present. The number of
vents and the amount of exterior air they allow into the crawl space is
important. Too much hot, humid air in the crawl space can actually add to the
problem. Follow these guidelines:
Without a vapor retarder present, 1 square foot of free vent area is
required for every 150 square feet of crawl space ground area.
If a vapor barrier is down, 1 square foot of free vent area is required for
every 1,500 square feet of crawl space ground area.
In some vapor barrier installations, if the soil is too moist or too high,
a thin layer can be removed. It also can be graded level. The plastic is then
spread across the floor. Make sure all debris is removed and you have a flat
surface. The plastic sheeting is overlapped by 6 inches and not always laid to
the end of the foundation. In homes with wood flooring, some moisture is needed
to keep the wood from drying out. Generally speaking, the vapor barrier should
cover about 75 percent of the crawl space. To read a fact sheet on crawl
spaces, visit the Forest Products Laboratory Web site, www.fpl.fs.fed.us/
documnts/techline/Crawl_ Space_Ventilation.pdf
Your Aug. 5 column on safeguards that would deter burglars from breaking
into homes when residents are away on vacation was informative. Just one
suggestion: Burglars often "case" a residence before a break-in attempt. One of
the things they look for is the bathroom lights going on and off. Most people
put timers in their bedrooms and living rooms but not in the bathroom. We
recommend that our residents install a wall timer in their bathrooms as an
added deterrent.
Andrew Silverman
director of public safety
Village of East Hills
Any step that makes it look as if someone is home is an excellent
safeguard. I find that letting a trusted neighbor know you're away is one of
the best preventative measures. And leave a phone number with that neighbor,
too. A few summers ago, our neighbors went away for a week and no one knew how
to reach them. They had an exterior water leak - the outdoor hose faucet broke
- and water was all over the backyard. If they had left a phone number, we
might have saved them some money on their water bill.
E-mail gary.dymski@ newsday.com.
