THURSDAY, FEBRUARY 7,
2013
Crawlspace Moisture
Control Brentwood, TN Reeves Crawl Space Services
615-290-2228 www.ReevesCrawlSpace.com
If you get three general
contractors together and the topic of discussion turns crawlspaces and moisture
control, you will probably hear six opinions. Folks, seem to have different and
often conflicting opinions about what tack is the best to take. The idea of
crawlspace encapsulation (sealing) has been around for a while now. Reeves
Crawl Space Services revolutionized encapsulation in the Tennessee and has
become the local authority on the subject.
There have been many studies on
crawlspace encapsulation during the past number of years. The US Department of
Energy and a non-profit research organization called Advanced Energy have all
done excellent and groundbreaking research in the area of crawlspace
encapsulation. Their research findings were instrumental in the last revision
of the International Building Code. They all concur in a few, very important
areas.
When considering your home, think
of it as a single system. Your HVAC system, insulation, windows, attic, living
space, and crawl space all work together. All of these building components need
to be optimized and balanced to achieve maximum comfort, performance and energy
efficiency. Your crawlspace is an important part of this system.
Your house is like a giant venting
system. By natural convection, air is drawn in through crawlspace vents and air
leaks. Because warm air rises, the outside air is drawn through the living
space (along with mold spores, odors, and moisture) and exhausted through the roof.
In the summer, your crawlspace is naturally cooler than the higher outside
temperature. So when the warm, humid outside air reaches the cooler crawlspace areas,
the moisture condenses on framing, plumbing, wiring, insulation and especially
HVAC ductwork and “sweats”, just like an ice water sweats on your kitchen table
in the summer. In the southeast it is not unheard of for crawlspace humidity to
approach 90% and actually rain inside the crawlspace.
The moisture in your crawlspace
creates an ideal environment for wood destroying organisms, mold, and mildew.
It can saturate and destroy the effectiveness of your insulation and promote
wood rot. And because of the venting effect, the humid crawlspace air, full of
mold and mildew spores, eventually finds its way into your living space
creating an unhealthy environment and causing your air conditioning to work
overtime to dehumidify the air. In as much as a vapor barrier can help, it won’t
stop the moisture coming in from outside.
So, the alternative to a vented
crawlspace is an encapsulated (sealed) crawlspace. Crawlspace encapsulation
involves sealing all outside vents, installing a high-performance vapor retarder
on all exposed wall and floor surfaces at or below grade, insulating the walls
and rim joist, and conditioning the air.
The building codes in most areas require the air in an
encapsulated crawlspace to be conditioned. That generally means adding a dehumidifier
or using the existing HVAC system to condition the air. The EPA and the
Department of Energy recommend using the existing HVAC system at a rate of one
cubic foot per minute of conditioned air per fifty square feet of crawlspace
area. A qualified HVAC contractor can add one or two 4” or 6” vents to a system
for a nominal cost. The vents are usually equipped with a butterfly valve that
can be adjusted to get the desired air flow.
Reeves Crawl Space Services prefers using this method since
the installation of the vents is generally less expensive than a crawlspace
dehumidifier. And since running a dehumidifier is about the same as running a
small refrigerator, the cost of conditioning the air with an HVAC system is
generally less than running a dehumidifier. Remember that you’re not trying to
heat and cool your crawlspace; you’re just adding a small amount of conditioned
air. A relative humidity target of 60% or lower is a good place to start.
Got questions about crawl space moisture in Tennessee?
Call us at 615-290-2228 or visit us on the
web at
www.ReevesCrawlSpace.com
Shaun Reeves ACE
Reeves Pest Control
www.ReevesCrawlSpace.com
www.ReevesPestControl.com
Keeping Tennessee Pest Free!
615-290-2228
931-223-8327
Shaun Reeves is the first certified entomologist in
Williamson County, TN.
Reeves Pest
Control is the premiere crawl space encapsulation company in Middle Tennessee.
