Your Crawlspace – 3 Must Knows

Crawlspace. That space under your house where you never go. Who knows what's under there? We act as if it doesn't matter. You know it's dirty. Undoubtedly uninviting. And it's certainly no place where the average homeowner wants to spend much time investigating … until you realize how important the environment within that crawlspace is relative to the air you breath, the health of your family, and the potential negative impact on your savings account.

According to Wikipedia a Crawlspace is “a basement someone cannot stand up in.”

Hardly respectful considering the important tasks a crawlspace performs. In addition to housing many of your homes utilities and allowing for service access, a crawlspace also acts as a buffer between the living space above and the moist ground below with it's soil gasses, animal and insect pests, and harmful organic elements.

So here we are. Staring straight into the stark reality that you have a crawlspace. It's not going away. What are the risks associated with crawlspaces and what can you do to mitigate those risks.

Crawlspace Risk #1 – Unhealthy Living Space Air

It is generally accepted that at least 40% - 60% of the air within the living space first spent time within the crawlspace. The living space above the crawlspace is much like a wick in lattern. It is always drawing air from below. This action causes the soil in the crawl space to dry up. There is moisture in the soil outside of the house. This outside moisture tends to be drawn in by the negative pressure within the crawlspace. As the air in the crawlspace moves up, new air is drawn into the space via the vents and the soil. For much of the year, the air outside the house has a higher humidity count than the air within the crawlspace. Thus a cycle begins. Moisture from the exterior air and the soil below constantly being drawn in to the space.

If the crawlspace has a dirt floor the SOIL GASSES that are naturally present within the soil will also be drawn up into the living space. Chief amongst the gasses worthy of note is RADON which is radioactive and causes cancer.

Where there is stagnant moisture and organic material – there is MOLD. The sub-structure of your home is wooden. We now have a dark, moist, environment with a food source for the fungi. This moisture vapor can pass through walls and floors. Some molds produce mycotoxins that can have serious negative health side affects especially to the old and the young. Those with weaker immune systems.

The question often arrises, why didn't previous generations suffer from the same structural design flaw.

In the 1970's the US was subjected to the OPEC Oil Embargo. This restriction in product caused the relative cost to rise. In response to rising heating costs efforts were made by contractors, designers, and homeowners to tighten up the home and reduce the “breathing” that had been allowed in previous designs. We now had air tight homes without the ability to change out bad air for good.

Crawlspace Risk #2 – Foundation Damage

The presence of moisture and the potentially damaging organic growth that is often times found on the wooden structural elements of the sub-structure will gradually weaken the foundation on which the home rests. If left unchecked the eventual damaging effects of this issue will completely destroy the structure. In fact, the real benefit that planet earth derives from organisms like mold is that is does exactly that. Mold consumes dead organic material and enables the recycling of those nutrients back through the ecosystem.

Crawlspace Risk #3 – Higher Household Operating Costs

In a vented Crawlspace with a dirt floor the cost of heating and cooling the living space dramatically increases. Blatant evidence of this is present for all to see when the floors are cold and the heating bills are high. In the cooler months the structure is drawing in cold air form the outside. In the warmer months the air being drawn in not only must be cooled but it also brings with it high levels of moisture.

Not only does the structure heat and cool more air than should be required but the mechanical equipment, namely the furnace and the air conditioner, must work harder reducing their effective life span and driving up not only short term operating costs but long term infrastructure costs as well.

What Can You Do About that Problem Crawlspace?

The generally accepted approach amongst architects, engineers, and contractors is to dry the space up and to seal the space from the outside elements. Like most of the problems we encounter in our human experience, the “devil is in the details”.

A time tested method of approaching a problem Crawlspace would resemble the following;

  1. Install a drainage system around the interior or exterior flank of the building footing and foundation to remove water at the lowest point.

  2. Drain that ground / storm water away from the structure utilizing either gravity or a mechanical solution such as sump pump and pit.

  3. Remove the vents within the foundation wall and install block and mortar to eliminate those points of entry.

  4. Depending on the level of soil gasses, your determination to encapsulate the space, and your budget, install at least an air-tight impermeable barrier between the crawlspace and the soil. After reviewing the data and weighing the budgetary concerns, many homeowners choose to seal up the entire space using a thick membrane product which can carry a life-of -structure warranty thus eliminating all future concern.

Is It Worth The Worry / Investment?

  1. The risk to your health is proven.

  2. Restoring damaged foundations caused by these issues is a booming business.

  3. Do the economic factors justify action? After doing the math and considering the gravity of the first two points many homeowners say “yes”.

Now, it up to you to decide.

Best wishes in your pursuit of knowledge and understanding!

Before and After

Before and After

David Perdicaris