We do more than just inspect your home for pest problems, we also look for any moisture issues in your crawl space. Using a moisture meter we can determine and diagnose any potential problems in your crawl space. We consider this a standard practice because high moisture can be conducive to many different threats including mold, mildew, various types of fungi, termites, and other wood destroying organisms such as powderpost beetles which are common in South Carolina.
When evaluating wood moisture content, we look for two important numbers. At 20% moisture content we consider that amount too high and excessive for a crawl space. We will stab the moisture meter into the wood members and floor joist and take readings throughout the crawl space. We take a minimum of 5 readings covering the center of the house and all four corners, but normally take multiple readings within each of the 5 sections. The readings can differ greatly from one floor joist to the next. We make sure to get as accurate of a reading as possible since various woods have different densities and can require multiple readings. It’s like a sponge, some soak up water better than others and wood does the same thing.
The wood is actually absorbing the moisture from the air which is a common problem here in the south, including South Carolina where we have high humidity throughout the summer. The humid air comes into the crawl space and the wood members soak it up. 20% is considered excessive because that is when you will have surface mold and mildew that will begin to grow on the wood members. At 28% wood moisture content you begin to develop wood-destroying fungi which promotes wood rot. It’s not the water specifically that makes the wood decay, its the resulting fungi that begins to decay the wood.
Standing water in the crawl space creates another potential problem. Sometimes it can be an easy fix by raking back mulch that is too high against some of the foundation vents. It could also be a more involved fix like installing vent wells to take care of the water. Standing water can also be caused by a poor grading job or a foundation that wasn’t water-proofed properly. In this case you might need an external french drain installed around the house or a sump pump inside the crawl space to capture the water on the perimeter as it comes in and pump it out of the crawl space.
Another option for keeping the wood moisture content down is a vapor barrier. This involves rolling out a quality heavy plastic in the crawl space, typically a 6 mil poly. We cut the plastic to fit around all the piers, nice and tight. We also stake it down to cover as much soil as possible in order to block the moisture coming up through the soil.
Moisture Control Methods
- You can increase the airflow in the crawl space by adding more ventilation, which may mean cutting in new vents or installing power vents with fans that kick on during times of high humidity. These do work and can help to reduce the moisture content but they are more inconsistent when it comes to being able to predict how well they are going to control moisture.
- The more predictable way to control the moisture is through a dehumidification system. You need a quality dehumidifier that is actually built for a crawl space environment, unlike those you find at Home Depot or Lowes that are mainly designed for basements or climate controlled settings. These cheaper versions will not last long in a crawl space environment compared to the ones designed specifically for crawl spaces which can last for years and years.
Call today to schedule a free Moisture Remediation Inspection: 866-442-7378