Reprinted courtesy of Temp Vents All rights reserved

Vented crawl spaces have successfully been utilized for over 65 years. Another option that the
homeowner has is a non-vented, closed or sealed crawlspace which entails the sealing of your
crawlspace by enclosing it with a barrier and insulation.
Here are just a few considerations:
• Sealing the crawl space inhibits the ability to do a visual inspection from your pest
control professional for termites and other pest or rodents.
• Un-vented crawl spaces may intensify biological contaminations such as mold and other
fungi. According to the EPA exposing hidden mold can result in mass release of spores.
An example might be opening of a closed un-vented space. Once opened it could result
in a mass release of spores.
• System failures over the life of the building are probable such as plumbing and HVAC
leaks. Vented systems can deal with the moisture and biological contamination problems
better than un-vented systems.
• Installing contractors are increasingly being held liable for systems designs and
installations. Will your contractor pay for the damages?
• There have been no studies of un-vented crawl spaces which evaluate the systems for the
life of a typical building; however vented crawl spaces have been a proven and effective
system for over 65 years.
• According to the EPA the way to control mold is to control moisture. Ventilation allows
for effective moisture control when designed properly.
• Does your insurance company insure a sealed crawl space? Many insurance companies
will no longer cover mold or other fungi in their standard Home Owner Policies.
If not addressed, moisture problems in the foundation can cause many costly
consequences, including structural damage. Often, these problems go
unnoticed by homeowners.
Moisture can create an environment that attracts insect populations and can
contribute to the conditions that can cause mold, mildew and wood decay.
This picture represents significant moisture damage overlooked by the owner.

 

Homeowner Bulletin
A properly ventilated crawl space in conjunction with these steps will help minimize the
potential for moisture related failures:
• Make sure that crawl space soil elevation is higher than the exterior soil grading
• Grade exterior soil away from the house on all sides (5% grade is recommended)
• Ensure all gutters, downspouts, overflow drain lines, etc. divert bulk water away from the
exterior walls of the structure
• Ensure all exhaust vents (driers, bath exhaust fans, kitchen exhaust fans, etc.) terminate
outside of the house and not into the crawl space
• Use a durable vapor barrier to cover the entire floor of the crawl space
• Maintain plumbing systems regularly to ensure that any leaks are addressed promptly
• Use proper amounts of insulation to avoid possible condensation on surfaces, including
any exposed pipes and around structural members
• Avoid the use of landscaping against the structure which may contribute to moisture
problems in the crawl space
• Incorporate capillary breaks to minimize moisture transfer from the soil to the structure
Ask yourself this question . . .
Do you want to gamble by employing the use of a proposed theoretical, non-vented crawl
space design that has not been tested or evaluated for the long term and may ultimately cause
more problems than those initially intended to address?
OR,
Do you want to employ a sustainable, vented crawl space design that has been used and tested
in real world applications for more than half a century?

Call Us Today at 919-557-1900 or Request an Inspection online