The crawl space has an integral role towards a home’s overall value as well as the living space above. Most homeowners in Fort Sanders Knoxville don’t think twice about their crawl space unless they have to make repairs to plumbing, heating ducts or house wiring. While often thought of as no more than a storage area, it also has a tremendous impact on the overall indoor air quality of the entire home.
The Best Clean Crawl Space In Fort Sanders TN
By default, the air quality of a crawl space is typically poor. Mold, mildew, radon gas and poor energy efficiency all create several problems. The air that circulates within it eventually makes its way up through the living space. Scientific studies show that up to 50% of living space air originates from the lowest level of the home. With homeowners more concerned about their home’s indoor air quality, the encapsulating of crawl spaces has become a popular solution for such problems.
A damp crawl space creates a safe harbor for harmful molds, in addition to dust mites, termites and other bugs that can infest the home. The presence of excessive moisture will also create a serious problem with the probability for the wooden structure of a home to deteriorate. Crawl space vents pose a further problem. While believed to be a solution to moisture problems, they, unfortunately, make the problem worse. As it turns out, the vents allow cold air and moisture in, which rises into the living area and therefore decreases the heating efficiency of the entire home.
Another all-too-common problem associated with crawl spaces is radon gas. Though it cannot be seen, smelled or tasted, radon is a radioactive gas that can contribute to poor health, including cancer. Radon gas makes its way through the earth, into the crawl space and the home’s living space. According to the U.S.E.P.A., radon gas is the number one leading cause of lung cancer in non-smokers.
Ignoring these various conditions is not recommended for both long-term health and energy usage. Fully encapsulating a crawl space – by both sealing and insulating – is a fully efficient measure in addressing such problems. It makes sense to maintain and improve the lower level area in order to maximize healthy living conditions and home resale value.
While there are several systems for encapsulating, a zero perm liner system that also insulates and reflects heat provides the most benefits. With a proper floor and wall liner, the area will not only be well insulated but will seal out moisture, bug infestation, and radon gas. Other components to look for in a system include a radon gas-dispersing drain fabric, a radon gas ventilation pipe, and a ceiling heat shield.
A complete system with all of the above components will allow any soil gasses – including radon gas – that naturally occur under the liner system, to wick through the drain fabric and escape out through the ventilation pipe. While improved indoor air quality is the primary benefit of a sealed and insulated crawl space, the homeowner will also appreciate a bright, clean, and dry storage area; the ridding of musty smells; less energy usage; and tax credits. Contractors encapsulating crawl spaces will have more to offer to their clients when they can assure the peace of mind with improved indoor air quality.
Crawlspace Vapor Barrier Mythbusters
Outlined below are the most common 4 methods I have seen used in installing a vapor barrier. If you talk to different builders, you usually will end up with many different methods of installing a vapor barrier in a crawlspace. Here are the most common:
1. Pea Gravel on top of plastic vapor barrier - This has to be the all time dumbest thing I have ever seen, and yet it is probably one of the most common. I have had builders tell me that the plastic on the ground KEEPS ground water and moisture from coming up from the ground. Now if there is no moisture or water in the soil, this might be possible; but if that was the case there would be no need for the barrier in the first place. So here is the basic idea - ground floor (bottom) - plastic (middle) - 4" pea gravel fill (top). Once the crawl foundation is built, builders install a 4 - 6 mil plastic on the ground and dump about 4" - 6" of pea gravel on top of the plastic. Eventually, what always happens is that water comes in from the walls and the ground floor and ends up on top of the plastic. So what you end up with is a swimming pool liner that holds water in the gravel for prolonged periods of time. Nearly all the water and moisture in the gravel back fill has to evaporate into the structure. Another example of building practices and science turning a blind eye to crawlspaces for decades.
2. Vapor barrier on top of ground floor - By far the most common practice for installing a vapor barrier. A 6 mil polyethylene vapor barrier is placed over any ground floor. Here is the idea - ground floor (bottom) - plastic (top). The ground floor could be river rock, pea gravel, dirt floor, sand, etc. The seams are typically overlapped 6" - 12" and almost never taped. While this will temporarily stop some moisture evaporation, it does not seal out moisture from the internal perimeter wall where most water penetration occurs. Also moisture can come up from the seams, and the plastic is not durable enough to crawl on. It nearly always ends up with many punctures and holes in it.
3. Vapor barrier on bottom of floor joists - This is rarely seen, and usually only home owners attempt this. This is probably the method that accounts for more wood rot than any other method. If you are even thinking of doing this, quit thinking and call a professional to fix your crawlspace. Most crawlspaces are vented and the cooler surfaces such as duct work, pipes, and the floor will condensate in the summer. The plastic will trap the condensation up against the floor structure and mold and wood rot will occur. Good intentions do not always produce good results.
4. Vapor barrier fastened to sill plate - There is a new industry in crawlspace repair that encapsulates crawl spaces. The process of encapsulation is to install a heavy think plastic liner on the floor and up the foundation walls. The plastic liner is fastened and sealed to the foundation wall and all the overlapped seams are taped. Every potential gap or seam in the liner is meticulously sealed to prevent any moisture from evaporating. Then the vents are sealed in the encapsulation system to prevent hot humid air from entering in the summer. There is another system being sold and installed out there being represented as an encapsulation system, but is far from it.
This "other" system is a 6 mil plastic that is ran up the foundation walls and stapled to the sill plate. None of the overlapped seams are taped. It is basically a glorified vapor barrier on top of the ground floor being ran up the walls and stapled to the wood. They seal the vents without properly sealing the moisture from the ground floor or foundation walls. The problem with fastening plastic to the sill plate is that moisture will "wick" up the foundation wall, and moisture will absorb into the sill plate and floor joists. They are giving free access to all the moisture under the liner to rot the sill plates and floor joists. Not to mention that all the moisture will evaporate up through all of the seams that aren't taped and the plastic liner is only 6 mil and eventually will puncture and tear. Be very careful in the contractor you choose to properly encapsulate your crawlspace.
A Vapor Barrier in Your Crawlspace is a Healthy Addition For Your Family
There are advantages and disadvantages in having a crawl space under your home. Advantages, perhaps, a slightly elevated home may be more attractive than a home on a slab. Plus, you can make repairs and modifications to plumbing, heating, and electrical services.
Disadvantages, a crawl space is an area that is never cleaned. Under the vapor barrier the humidity is always 100% so mold and bacteria are always present. Termiticides, other chemicals, even rodent droppings may be present, and odors and gases that emanate will migrate into the home's living space unless proper ventilation is installed. Whether on a slab or elevated, if radon is present, good ventilation is required.
There are several technologies on the market in regard to moisture control. One is encapsulation, sealing the crawlspace. Though this might lower humidity, it's costly and there is no dilution or replacement of stagnant, poor quality air. Again, if radon is present, ventilation is required.
Another technology is to install a dehumidifier in the crawl space. This can lower humidity, but again will not dilute or replace the stagnant air. Another point to think about is that the dehumidifier will be costly to operate. More importantly, using a dehumidifier requires you to close tightly the crawl space. Thus, the home's living space air quality is going to be lowered because the crawl space air is not diluted and replaced with fresh outdoor air.
Some systems use a dehumidifier control (dehumidistat) to operate a crawl space vent fan. This sounds like it's going in the right direction. However, the technology isn't quite right. Here's why. Suppose the outdoor air is getting worse (wetter). Though the dehumidistat control is in the crawl space, it will quickly recognize this wetter air condition and begin ventilation, even though ventilating is going to make crawl space wetter. Another problem with a dehumidistat control is that most of them are not made for the difficult environment of a crawl space, so their warranties are short, 30 days to 1 year maximum for the dehumidistat.
There is another system that uses special technology different from all the others mentioned above. This special technology makes a comparison of the actual moisture content of both the air inside the crawlspace and the outdoor air. The result is that it pauses and does not ventilate when bringing in outdoor air is going to make the space wetter. Then, as the outdoor air is getting drier and is able to improve the moisture and air quality in the crawlspace, then this ventilator moves a lot of air which dilutes and replaces stagnant air, ultimately improving your home's living space air quality.
This system, called the Smartvent, is made in the USA, is used from Florida to Alaska... San Diego to Nova Scotia.
This system is a proven system, and it is the only system to have undergone a year long test where crawl space humidity averaged 46%. Besides the unique technology this system employs, it also has the longest warranty of all ventilators, five years.
Crawl Space Masters Specializes In Crawl Space Encapsulation in Fort Sanders TN.