crawl space encapsulation Chattanooga, Tennessee

The crawl space has an integral role towards a home’s overall value as well as the living space above. Most homeowners in Chattanooga Tennessee  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.

crawl space drainage

The Best crawl space insulation In Chattanooga 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.

crawl space definition

10 Reasons to Encapsulate Your Crawl Space

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.

sealed crawl space cost

Basement Waterproofing Contractors - Make Sure They're Busy

Crawl spaces are inherently dirty smelly places that can contain all types of unwanted odors from mold & mildew to urine & feces. Some areas of the country can even have soil underneath the home with odorless, harmful gases like radon gas. I'm a big believer that the best long-term solution to solve these problems is to encapsulate the air underneath the home with a liner system. It is a inherently impossible to keep rodents, bugs and mold out of the area underneath the home since the soil is exposed - but it is relatively simple to create a barrier between the home and crawl space the keep out all these unwanted nuisances.

I had a very nice lady write me the other day telling me about this house she had just purchased that formerly had many cats living in the crawl space and they left behind the smell of a giant litter box underneath her home. The odors were coming up through the wooden floor and creating a very fowl smell in the house. She told me she tried all different solutions: spreading baking soda, spraying an enzyme treatment originally intended for carpets & laying down new top soil - needless to say none worked. I wrote her back, apologized for her wasted time and suggested that she treat her crawl space like a wild beast that you can't defeat, only contain. She took my advise, installed a crawl space encapsulation system and the smells immediately went away.

Permeability Rating

Encapsulation systems are rated by permeability - 0.000 is the best, normal plastic is 0.01 and wood is 0.2. To stop all smells, moisture and gases look for an encapsulation liner system with a 0.000 permeability rating. A zero perm liner will also completely weatherize the crawl space and save on energy bills since the outside air won't be able to leak into the home.

Thin Liners Don't Encapsulate the Crawl Space

I can't tell you how many times I've received a call or been sent an email from a homeowner telling me how they went to Home Depot, bought a liner system as thin as a trash bag, spent an entire weekend installing it then didn't solve their problem. Cheap store bought liners are typically 6-12 mil, 0.01 permeability and even new they don't stop gases like Radon - they are also easily chewed through by bugs and rodents leaving the crawl space a year later leaking air like a sieve.

What to Look for

40 - 60 mil thickness, 0.000 permeability and antimicrobial so mildew can't grow on the liner. Encapsulation systems don't need a contractor to install (although trust me they won't tell you that). Look for the Energy Star Rated logo.


Crawl Space Masters Specializes In Crawl Space Encapsulation in Chattanooga TN.

http://crawlspacemasters.com/tennessee/