Crawl space encapsulation, also called finished basement construction, is the process of closing off a crawl space or “well” to prevent moisture from entering the home. A sump pump and dehumidifier are adding to this sealed area, making it inhospitable to mold and mildew. There are two types of crawl space dehumidifiers, electronic and hydronic. Some homeowners choose to invest in both so they have full access to their crawl space’s water supply should it become compromised.
Crawl space insulation consists of sheets of foam, cellulose, or synthetic materials that are installed between the soil and the foundation. Insulation is effective at reducing humidity but not at preventing water entry. Surrounding walls will still be exposed to moisture if there is no insulation; the only protection is a vapor barrier. If the walls are constructed of concrete or bricks, waterproofing will need to be done before the insulation.
Concrete walls may have cracks or openings that will allow moisture into the home’s interior. If the holes or cracks are small, vented crawl spaces can be installed around them using silicone caulk, exterior wood fiber batt, or other forms of foam or membrane. The interior of the hole can be lined with mineral wool or wood chips to keep molds and mildew at bay.
If the holes or cracks are large, vented crawl spaces will be required to be sealed off with a vapor barrier. These barriers come in different configurations and materials and should be chosen depending on the space’s moisture level, as well as its ventilation. Natural stone and brick are among the most popular choices for vapor barriers, as they are easy to clean and maintain. Wood, however, is a poor choice for larger crawl spaces and should be used only in small areas where moisture and mold are unlikely to be an issue.
Once the outer layer of insulation has been installed, it is time to install the second inner layer. Fiberglass is a good material for this application, as it is relatively inexpensive and tough. It is also lightweight and easy to install. A fiberglass liner should be placed on the floor sub-floor, then wooden batt boards or drywall below it. After insulation is in place, a vapor barrier should be applied to the upper and lower walls, and then the floor. Finally, the roof should be covered with another layer of fiberglass or cellulose fiberglass.
After the initial insulation process is complete, a vapor barrier should be applied to the outside, then the inside. Wood or mineral wool is great choices for this application, since they are easy to clean and maintain. When finished, the surface of the crawl space will be protected from moisture and mold by a vapor barrier and moisture proof upper and lower walls and ceiling.
Air Ducts & Humidifiers – Add a ventilation system to your crawl space can be expensive and time consuming. However, if you have an existing duct system, you can simply retrofit to a ductless system. A traditional air conditioning system includes an air ducts and a humidifier. Ductless systems only include a humidifier, which has no maintenance and is less expensive over time. The benefits of ductless systems include low energy usage, better indoor air quality, more flexibility and energy efficiency.
If you are considering crawl space dehumidification, you should also consider a dehumidifier with a vapor barrier. In areas where there is significant humidity, a vapor barrier will help prevent wood rot, stains and mold growth due to moisture. In areas where you would like to use a dehumidifier, but you don’t want to build in a vapor barrier, there are endless dehumidifiers that you can purchase. These are much quieter than their certified counterparts and can also effectively lower the relative humidity in your home. Of course, you may need to try several different models before you find the one that works best for your needs and your budget.