Wood Destroying Fungus

• Moisture can attack wood and trigger decay, fungus and wood rot resulting in structural damage.
• The foundation can crack.
• Floors can warp.
• High moisture levels under the home can lead to mold, mildew and cause the spread of fungus
  spores leading to odors and unhealthy air conditions.
• Mold spores can aggravate allergies, asthma and hay fever.
• Moisture in the crawlspace can dampen insulation reducing its effectiveness.
• Dark, damp area are hospitable environments for termite and other wood-destroying pests.

Wood Destroying Fungus

Poor Ventilation

Ventilation Systems

Ventilation is a system of intake and exhaust to promote the necessary free flow of air throughout the crawlspace.

Adding ventilation is a simple way to help reduce moisture buildup. Ventilation will allow air to enter and exit the space, carrying heat and moisture out with it.

There are two types of ventilation that can be used, passive and active.

Passive Ventilation. Passive ventilation relies on the passage of air in one vent and out the other, depending on the direction of the wind.

Active ventilation. Powered foundation vents are vents with small electric fans built into them. Active ventilation is used when there is a serious moisture problem, or for difficult-to-vent areas.

Vapor (moisture) Barrier

A polyethylene vapor retarder or plastic sheet can be installed on the floor of the crawlspace to help retard moisture from seeping up through the ground.

When installing vapor retarders, use a 4-6 mil polyethylene vapor retarder installed on 80% – 90% of the floor of the crawlspace.

The polyethylene should not completely cover the ground. If the moisture supply is completely cut off, hardwood floors and other wood may shrink excessively. A vapor retarder that completely covers the floor can hold too much moisture and never get a
chance to dry. The ground needs some air to breathe.

Vapor (moisture) Barrier