When was the last time you were inside your crawlspace? Six months? A year or longer? Crawlspaces are often the most neglected areas in a home. They are expected to be dirty, wet and an altogether unpleasant place to spend time. So much energy is spent focusing on maintenance of interior spaces that the crawlspace is forgotten and its impact on the integrity of the structure and the health of those inside is overlooked. Did you know that up to 50% of the air on the first floor of a home comes from the crawlspace? Think about breathing in all that unpleasantness and what it could be doing to your health. Breathing in the dust, mold, and products of pest infestation doesn’t seem like the best way to keep you and your home healthy.
One of the most important things you can do to protect the structural integrity and air quality in your home is ensure that the space under the living area is well maintained. One of the most important aspects of a healthy crawl space is to be sure it has a functional vapor barrier installed. What is a vapor barrier? Also sometimes called a moisture barrier or crawlspace lining? A traditional vapor is a layer of plastic, usually at least 6mm thick, that covers the ground of the crawl. Its function is to limit the amount of water vapor and humidity that makes its way up from the ground. By limiting moisture, the vapor barrier prevents against mold and water damage to the structure of the home. It also discourages pests that may burrow up from the ground. Prolonged exposure to water and mold will deteriorate floor joists and supports that are critical to the home’s stability. Also consider the piping, appliances, and electrical wiring that frequently run throughout a crawlspace. Keeping these things dry are important for safety and longevity of those items.
Though they may seem unrelated, an adequate vapor barrier can also impact the attic space. (https://centralkymold.com/stack-effect-say-what/ ) The unchecked water or humidity in a crawlspace causes warm, humid air to travel up through the living space and settle into the upper levels and eventually the attic. This can cause warped flooring, sweating walls and mold growth. These problems can be further complicated when the home has fiberglass insulation installed in the crawlspace. Moisture from the ground settles in the insulation and causes it to sag and fall. Once this happens the insulation is no longer functioning properly and the exposed paper backing can become a great food source for mold. One problem always leads to another right? And for what it’s worth; we recommend no fiberglass insulation in crawl space and if you must… paper side up please!
Like most things, vapor barriers need replaced over time. The plastic can become brittle or torn due to changing temperatures, frequent exposure to ground water or pests. A seemingly minor tear in a vapor barrier can be enough to allow significant amounts of water into the space. This is problematic because the water then becomes trapped on top of the plastic with nowhere to reenter the ground. The water evaporates upwards into the home’s floors and throughout the living space. Mold requires moisture and an adequate food source like wood, paper or other organic materials in order to grow thus making a crawlspace an ideal place for it to thrive and grow unchecked. In many homes, the crawlspace is home to a furnace and ductwork. Keeping mold out of these places is important because they can and will easily circulate mold spores, dust and other unhealthy air throughout the living area. Once inside, those mold spores can find additional sources of moisture (like humid air coming up from the crawl) and food to take hold and continue thriving. Considering this, it isn’t hard to figure out why many interior mold problems often begin in the crawlspace.
We frequently take calls from concerned homeowners and potential buyers wanting to test a crawlspace for mold. Typically, we do not recommend testing a crawlspace for several reasons. A mold test is largely validated by how it compares to air samples taken outside. Mold counts are compared to those naturally occurring in the outdoor setting to indicate if a home’s air has higher than normal occurrences. This is almost impossible to do in a vented crawlspace because of the exposure to outside air and the natural occurrence of mold in the dirt or gravel floor. Surface samples can provide some insight but not much in the way of overall crawlspace health. Surface samples consists of testing small areas of the crawlspace using an adhesive tape. Those results will indicate how much and what type of mold is present, but only in that exact spot. It is difficult to generalize those results to the crawlspace overall and the presence of some mold on those surfaces is to be expected. The best method for determining mold in a crawlspace is through visual inspection of the space. If mold is visible on several surfaces, wipes off relatively easily (unlike a stain) and can be attributed to a moisture source chances are good that the area needs remediated or steps should be taken to prevent the problem from worsening. A vapor barrier is a critical start to that process.
There are several options when considering replacing or installing a new vapor barrier. As mentioned above, a traditional barrier consists of 6mm plastic spread along the crawlspace floor. Seams are taped or overlapped depending on the space. An enhanced vapor barrier is also an option for spaces more prone to water entering along walls or foundations. This plastic is thicker (9mm reinforced) and covers the floor as well as a portion of the foundation walls. Plastic is attached along the wall but below vents to allow adequate air flow to the space. Finally, complete crawlspace encapsulation is an option for those interested in completely sealing off a space from outside air or moisture. In this case, the thick plastic covers the floor, walls and pillars. Vents are sealed to prevent outside air from entering. When encapsulating a crawlspace, it is important to take note of appliances that may be located under the home, the need for a dehumidifier, and how the home is insulated. Encapsulation is becoming the standard in new construction homes and is ideal when the right conditions are met.
For the health of your home and family, it is important to be aware of the condition of your crawlspace. Take the time to venture under the house and look for signs of water damage, mold growth, or an inadequate vapor barrier. It can be difficult to spot problems if you aren’t sure what to look for. Keep an eye out for fallen or wet insulation and insulation that is installed paper side down. Check floor joists for evidence of water, sagging or soft spots caused by prolonged moisture exposure. Missing or torn vapor barriers. Remember, a vapor barrier that has been pulled to one side or does not cover the entire floor is a problem. Check vents to be sure they are not blocked by leaves or anything that can prevent proper air flow. Remove any trash and avoid using the space for extra storage. Trash can serve as additional food source for mold and contributes to torn and disturbed vapor barriers. If your crawlspace is prone to significant water intrusion following heavy rains or because of the home’s location consider installing a sump pump to quickly remove water. Be sure the sump pump is in location that the water will easily flow towards it and that it drains outside the crawlspace (yep, we’ve seen it) and to an area where the water will not easily reenter. Finally, inspect the crawlspace entrance to be sure it is properly closing to prevent water or animals from entering the space. As always, if doing the crawl space army crawl isn’t your thing; call us and we’ll do the dirty work for you! We install all types of vapor barriers and can help correct mold problems that have occurred due to insufficient or lacking barriers.