One of the biggest advances in building science over the past decade is the research that proves definitively that vented crawl spaces are bad. If you’ve ever been in one, you know it’s true. They’re damp, dark, and critters have easy access to them. The batt insulation falls down; the air smells musty & moldy. Worst of all the crawl space communicates with the house, so that bad air (and the occasional critter) gets into the living space above. In 2002, Advanced Energy studied a group of 12 houses in North Carolina. What they found is that the 8 that had encapsulated crawl spaces had relative humidity that stayed less than 60% all summer, whereas the 4 vented crawl spaces had humidity levels that were the same or higher than the outdoor humidity.
The reason the vented crawl spaces had higher humidity is actually pretty simple. Warmer air can hold more moisture, so in the summer time, the outdoor air can bring a lot of extra water vapor with it when it comes into a crawl space through the vents. When that warm, humid air comes into the crawl space and cools off, the relatively humidity can go even higher. If you want to learn more about the details of this research, you can find that and more at Advanced Energy’s crawlspaces.org website.
So, what exactly is crawl space encapsulation, and how does one make an encapsulated crawl space?
As you have read so far, vented crawl spaces have a number of problems that seriously degrade a home’s comfort, health and performance. So if you think about it long and hard your home is a place that you spend a lot of time. If the home is uncomfortable, unhealthy, and not performing what does this do to you and your family? Let me give you a thought: it makes you UNHEALTHY, UNCOMFORTABLE and COSTS YOU MONEY. The best alternative is to encapsulate the crawl space, or else design it in a way it’s together for your new Home.
Here are the basic features of an encapsulated crawl space:
- 100% coverage of the ground with a vapor barrier
- Seams and junctions of vapor barrier sealed
- Sealed crawl space vents
- Insulated foundation walls and band joist (usually)
- Conditioning of air with one or if not all three methods: 1) dehumidifier, 2) small amount of supply air from HVAC system, or 3) small exhaust fan
The benefits of this treatment are significant. As you’ve read, the relative humidity will stay below 60%, even when the outdoor humidity is much higher. With dehumidification, it’s not difficult to reduce the humidity to less than 50%. This gives you control over your crawlspace the ability make your house a HOME.
- Better air quality in the crawl space, which means better air quality in the living space
- Greater energy efficiency. The Advanced Energy studies have found nearly 20% reductions in energy use in homes with a conditioned crawl space.
- Fewer critter problems
- Greater durability of floor, HVAC equipment, and other components in the crawl space
- Greater comfort in the home because of reduced humidity and crawl space temperatures close to living space temperatures
There are also, of course, some other necessary discussions that come with this method of treating crawl spaces. For one, a crawl space with atmospheric combustion appliances should not be encapsulated; there are options that we can take to solve this issue, such as new sealed combustion appliances or build a sealed appliance closet that is vented to the outside. Second, all bulk water problems need to be addressed before encapsulating.
Now that you understand the benefits of encapsulation and are ready for a quote from Ross & Witmer (or another company), it may be immediately apparent to you that the best move is to have the work done. If, however, you’re hesitating to spend thousands of dollars on a part of the house you rarely visit, let’s look at some of the reasons to encapsulate:
- Breathe easier. Vented crawl spaces have a huge negative impact on indoor air quality.
- Reduce the chances of costly floor repairs. Moisture rots wood and causes hardwood floors to buckle.
- Enhance comfort. Floors won’t be cold in winter. House won’t be muggy in summer.
- Lower energy bills. Crawl space encapsulation can reduce energy bills by up to 20%, according to Advanced Energy’s research.
- Make your heating & cooling equipment and ducts last longer. An air handler and ducts in a vented crawl space will not last as long as equipment in a conditioned crawl space.
- Qualify for rebates and tax incentives. Some utilities offer rebates. The federal government has tax incentives for home performance improvements. Some state and local governments offer incentives as well.
- An encapsulated crawl space is an attractive selling feature. Potential buyers comparing two similar houses will find the one with an encapsulated crawl space more appealing.
10% is a lot of MONEY!
Because when and if Buyer view your home with a damp, moldy crawlspace its viewed as a fixer-upper, they are going to pay you 10% less than otherwise, that’s if they buy it at all.
Using this Example
|What is your home worth?||The estimated cost of not fixing your crawlspace in property value alone.|
You can now see the idea, and this does not take in to account the cost of any remediation, repairs (wood rot), or higher energy bills each month while you live there.
THE MORAL OF THE STORY
It’s not CHEAPER to keep her
It’s BEST to INVEST
Make your HOUSE your HOME