We’ve been getting a lot of phone calls lately from clients that are frustrated with their sealed crawl spaces. In the Charlotte, North Carolina market, and the surrounding counties, 90% of residential construction is crawl space construction. Since crawlspace construction is problematic especially during the hot humid summer months, the Charlotte market has had an explosion of companies claiming to be experts offering a sealed crawl space solution. The solution is 10 to 15 years old, and has some inherent challenges. Most of these companies are jumping in on the feeding frenzy as a way to sell more things to their customers. The challenge with this scenario is most of these companies have very little to no education on why the problem happens. Franchisees send out commission based sales people to the customer’s home claiming to be experts with a basic crash course of 2 to 3 days from the manufacturer, a laptop, glossy brochure, and a go get em tiger approach towards the public that they pretend to serve. Since the salespeople are commission based they tend to over design and embellish the problem in an attempt to make a big sale. I am finding customers are being overcharged two to three times what the actual repair value was worth. High-pressure sales techniques such as fear, intimidation, and flat-out lies about potential health threats have been reported. This is a very disingenuous tactic and gives the industry a black eye. Here are the facts about the challenges with encapsulated crawlspaces:
1. When you encapsulate a crawl space, you encapsulate all of the odors and smells inside the space
2. Construction materials such as wood members, insulation, plastic, the acidity in the soil, etc. all off gas odors, and these odors can percolate up into the living areas.
3. HVAC systems that are installed inside the crawlspace using natural gas can also be a challenge inside a sealed crawlspace especially if it is not properly vented at the time of construction.
4. The heavy mil plastic that some of these companies use to encapsulate the crawlspace often off gas terrible odors that are often reported right after the install.
5. If there are currently any biofilm contaminants infesting the floor joists, insulation, or subflooring, these fungal or mold colonies also off gas odors that can now percolate up into the living spaces.
6. If the crawlspace was encapsulated with a drainage problem, moisture can build up under the liner and cause the development of mold which off gases odor that smells like cat urine. This is a huge problem as most companies do not install foundation drains when they encapsulate.
7. Without the induction of fresh air, there is no way for these odors and smells to escape, so they grow in intensity and often get worse during the summer months.
8. Encapsulated crawlspaces require an expensive dehumidifier to reduce moisture. Dehumidifiers are humidistat controlled devices and are extremely inefficient in crawl spaces especially in cooler temperatures and require 800 Watts of power to operate. This can increase your power Bill $15-$20 a month in certain cases.
9. Because dehumidifiers are humidistat control devices, they do not turn off at the right time and could potentially overheat around the compressor. This is a challenge with store-bought dehumidifiers or the big commercial jobs. Dehumidifiers often need to be replaced every 2 to 3 years, and this can run the customer $1500 at each replacement.
The good news is, if you are having challenges with your sealed crawlspace, the crawl space can be retrofitted with a dewpoint controlled fan system. This system uses state-of-the-art technology with a series of interior, exterior, and wood moisture sensors that gather atmospheric data and efficiently control the introduction of outside air into the crawlspace when it is conducive for exchange. Basically, if it’s drier outside that it is under the house we utilize the outside air. When it is too cold to hot or too moist outside we block that outside air and utilize the internal dead corner fans, and if necessary a backup dehumidifier that is tied into the controls for peak efficiency.
If you have a sealed crawlspace that is giving you challenges, or are considering encapsulating the crawlspace, please give us a call first to get educated on the science before making that decision. We are here to help.
Don’t encapsulate! Ventilate!