Crawl Space Service

Crawl spaces should be insulated and sealed

Many building experts recommend against crawl spaces because they have the water problems of a basement with almost none of the storage space, at much higher cost than a slab.

Still, sometimes a crawl space makes sense. Crawl space walls should be insulated with rigid foam or closed-cell spray polyurethane foam, and should be sealed rather than vented.

Crawl spaces should be treated as if they were miniature basements, which is exactly what they are. The best current practice is to make a crawl space a conditioned area like the rest of the house. This is permitted by newer versions of most building codes, and is much better for the house and residents.

 Vapor Barrier

A vapor barrier slows or prevents the evaporation of ground moisture into the crawl space air. If coupled with a waterproofing system, moisture and water can be expelled from the crawl space before it can cause problems. No more rot, rust, mold, odors, insects or other moisture-related problems.

A vapor barrier, by its nature, resists the passage of air. By stopping air movement from the ground, it can also turn your crawl space into a semi-conditioned space – one that is close to the temperature of the living spaces above. When that occurs, your floors feel warmer in winter and your energy bills go down.

A vapor/air barrier can also slow or block most of the movement of harmful gases, such as radon, from the soil. Coupled with a radon mitigation system (in the event that radon is present in higher than acceptable levels), a vapor barrier can significantly reduce radon levels in the home.


If your crawl space suffers from mold, chronic dirt, and humidity, then you may consider crawlspace encapsulation as a solution. This technology separates the crawl space and the ground using a vapor barrier, creating an additional envelope of protection between the building and outside weather. Crawl space encapsulation is one of a number of energy-saving processes which reduce heating bills and ensure that your home is energy efficient.

Before you consider installing crawl space encapsulation systems, make sure that your crawlspace is protected against vermin and fungi. Both damage the seal around the vapor barrier.

Check how your crawlspace will be sealed against moisture. The best crawlspace encapsulation methods involve more than simply laying a plastic liner. Installing a low-grade liner will not do much to prevent humidity and mold from regrowing. It is better to purchase a better standard of vapor barrier.

Crawlspace encapsulation prolongs the life of your crawl space, as it reduces temperatures and limits humidity, making it less vulnerable to insects such as termites, and fungi that can decay wood. It also greatly improves the air quality, both in the crawl space and in the home itself.


A crawlspace dehumidifier is the homeowner’s weapon against mold and mildew. It is important to buy a crawlspace dehumidifier with the correct capacity; otherwise, it will not remove enough moisture to combat the mold.

Humidity Level and Air Changes Per Hour

The first step to choosing the correct crawlspace dehumidifier for your home is to check the humidity level of the space where the device will be working and determine the air changes per hour required for your degree of moisture. An exact measurement can be determined with a hygrometer, which is a relatively inexpensive gauge to purchase, but there is a “rule of thumb” test which may suffice.

  • Moderately Damp – During humid weather, it smells musty and feels damp; 3 air changes per hour required.
  • Very Damp – The area feels damp and musty in any weather; 4 air changes per hour required.
  • Wet – There is visible water leakage, mold or mildew; 5 air changes per hour.
  • Extremely Wet – You see standing water; 6 air changes per hour.