Beware… an invisible area of your home may be making you sick!

Under the floors of even the most beautiful and expensive homes is an area rife with dust, disease and death. This small dark world is the crawlspace of your home, and although it’s out of sight, this deadly environment permeates the air you breathe and affects the health of the entire structure… and it’s inhabitants.

A crawlspace is a shallow and uninhabitable area located between the soil and the first floor of the home. It is typically excavated below grade and provides air space and access to the foundation, framing, and utility systems running below the floor.

For humans, crawlspaces are claustrophobic and dangerous places that can have protruding nails, live electrical wires, constricted pathways, raw sewage, polluted airborne dust, and inhalants laden with fiberglass, asbestos, mold and pesticides. Except for the occasional inspector, humans do not frequent crawl areas, but they are certainly bustling with life.

All manner of animals, dead and alive, lurk in the dark reaches of the crawl area including mice, rats, snakes, raccoons, skunks, possums, lizards, scorpions and poisonous spiders like the Hobo, Brown Recluse and Black Widow. Rats and mice, which absolutely love your crawl area, leave behind a trail of urine and feces that contributes to 35 human diseases including the deadly Hantavirus pulmonary syndrome. Rodents poisoned by pest control efforts seek moisture and will universally travel to a wet crawl area to die.

So your crawlspace is more than likely a nightmare that is not only bad for your health, but also detrimental to the integrity and durability of the rest of your home. At this point you might be asking yourself: why does anyone have such a thing, and what can be done to fix the situation. To answer, let’s examine some construction history and explore a bit of fresh thinking that may help clean up your crawl area once and for all.

During the building boom after WWII, contractors found that it was advantageous to lower the profile of their homes. They accomplished this by reducing the height of the foundation walls and building the structure over an excavated access area with an exposed soil bottom. This was easier and less expensive to build because less excavation and smaller foundation walls were required than for a full basement. This was not only cheaper but also allowed for building in areas where full basements were either not possible or not needed. Also wood framed floors made more comfortable living spaces since concrete floors were cold, hard and unpopular.

Because the floor of the crawlspace is below the surrounding grade, water will naturally pool there if given a chance. Unfortunately, moisture is the enemy of your home and it is especially detrimental in your crawl space. Moisture in the crawl space can damage wood and insulation, leading to dry rot and decay while creating conditions attractive to infesting pests including termites and ants. Crawlspace moisture can come from many sources including exterior ground water, gutter overflows, plumbing leaks, condensation, ground vapor and humid external air which can keep moisture levels exceptionally high.

In the early 1950s crawlspace foundation vents were introduced in an attempt to reduce moisture levels and eliminate humidity in crawlspaces. In fact, the Uniform Building Code until recently required that all crawl space foundations be ventilated. Because of this, almost all of the structures in the US with crawlspace foundations are vented to the exterior. Over time though contractors and inspectors realized the vents that were installed to remove humidity in fact promoted the increase in humidity levels in most crawlspaces. Vents actually allow hot humid air in the summer months to enter the cooler environment of a crawlspace. The humid air condenses and creates even higher humidity levels under the home. This eventually leads to heavy mold and fungus growth.

Air moving through the crawlspace naturally flows upward through the home bringing polluted crawl space air directly up to living areas through open joints between floorboards, registers and plumbing penetrations. This slowly traveling, invisible, smog cloud carries with it mold spores, odors and any harmful particles residing in the vicinity.  A poorly sealed duct system can also ‘suck’ this contaminated air from the crawl space directly into the breathable air inside your home. This is not only bad for your health it ruins any energy efficiency of your HVAC system.  Radon from the soil can also leech up from the crawl area, contributing further to an unhealthy environment.

Building codes are changing now to allow builders to construct conditioned air crawlspaces that eliminate foundation vents. The new building codes contain an unusual provision that allows code enforcement officials to deviate from the standards if they believe conditions are such that the ventilation standard is counterproductive. This is good news because eliminating crawlspace ventilation to the exterior is the first task in making your home healthier.

For long-term health, structural protection, energy efficiency and durability it is important to consider a professional crawl space restoration plan. Crawlspace remediation plans involve improving physical access, cleaning out polluted dust and debris, mold removal, temperature control and eliminating and preventing moisture, animal access and insect intrusion. This is a great plan, and like many plans it is easier said than done.

The entire area must be cleaned to remove debris and contamination. Construction debris, live animals, carcasses, contaminated dust, mold and any other foreign material must be removed.

All moisture sources must be tracked down and eliminated. This means addressing external sources such as defective grading, drainage, gutters and ventilation as well as internal sources such as leaks, broken ducts and subterranean springs. A proper vapor barrier needs to be installed to prevent moisture and radon moving from the soil into the home.

After a clean, dry space has been created, the air in the crawl space can be conditioned and dehumidified by one of several different ways depending on the individual situation. Properly sealing and conditioning the crawlspace is key to energy efficiency in the home. When your crawlspace temperature is not influenced by outside air conditions the amount of energy required to heat and cool your home is dramatically reduced.

A vapor barrier is a critical component to prevent the movement of moisture and gasses from the crawl area to the rest of the home.  It acts as a physical shield that repels moisture and keeps it from entering the living areas.  Vapor barriers must be continuous and unbroken to be effective.

Executing a comprehensive crawlspace remediation plan can dramatically improve the health of your home and it’s occupants. It can also significantly reduce your home’s utility costs and improve its long-term durability. Most of all, you can literally breathe easier knowing that what was once the nastiest, filthiest place in your home is now one of the most fresh and pristine.

Working in the crawl area to make all this happen is not easy and can even be dangerous. We highly recommend experienced professionals do the work using eco-friendly materials as much as possible. Talk with a licensed home improvement specialist or builder who is experienced in this kind of work to see what is best for your home. All restorations should be properly permitted, professionally supervised, and inspected by local code enforcement officials. We also recommend that you have the project photo documented from start to finish. The before and after shots will leave you delighted with your efforts and your healthy crawlspace will be highly valued by future owners.

The “greening” of the construction industry has been driven in part through the critical reexamining of many previously accepted building practices. Asking simple questions like: “why do we build this way?” and “what can we do that is better?” can help inspire us to think creatively to solve problems in a more sustainable context. Crawlspace remediation is a good example of this kind of re-thinking.