Why a “Conditioned Crawlspace”?

As a builder, I am often asked what are some of the indications of a well-built home? In this blog entry, I will discuss one of those indicators, the ‘conditioned crawlspace‘.

Simply put, a conditioned crawlspace is a crawlspace that is ‘conditioned’; meaning that the air in it is heated and cooled just as the home is heated and cooled. In a traditional crawlspace home, foundation vents are present, intended to serve as a means for air to circulate, keeping the crawlspace area dry and free from moisture. However, with the high humidity levels in our area of the country, this rarely happens. Instead, crawlspaces are often characterized by a damp, musty odor due to the high levels of moisture. Moisture in a crawlspace not only presents an unpleasant odor, but, over time, it also has a detrimental effect on the building materials to which it is exposed. Oftentimes, floor joists and the insulation in a crawlspace become damp and can eventually rot. The growth of mold can also be a concern. Obviously, issues like these can present serious problems for a homeowner.

So, what is involved in building a conditioned crawlspace? In our homes, we typically elect to pour our foundation walls instead of using CMU/block walls. Solid concrete walls present a more effective barrier between your crawlspace and the surrounding earth and water (from rain, sprinkler, etc…) and do not allow water intrusion like block walls do. By using poured concrete walls and heating and cooling the crawlspace, you create several positive factors that are beneficial.

First of all, since you are heating and cooling the crawlspace, there are no issues of moisture and humidity in the air as you are controlling these factors. This as opposed to the weather outside controlling them for you.

Secondly, you are not allowing the ground floor of your home to be impacted by the cold or hot temperatures that are present in a traditional crawlspace. Have you ever walked into your tile bathroom floor in the winter and noticed how cold the floor feels? Part of the reason for this is that the air in your crawlspace below that floor is as cold as the outside air. Even with code compliant insulation, that cold air impacts the temperature of your bathroom floor, as well as your entire house. A conditioned crawlspace is insulated and temperature controlled.

Finally, HVAC duct-work, and often HVAC equipment, is located in the crawlspace of a home. In the winter, your unit is carrying warm air through a cold crawlspace. That presents the same problem as your duct-work trying to carry cool air to your home in the summer in a 120 degree attic. (We use spray foam to to insulate our attics but that is a different topic for another time). A conditioned crawlspace is a key factor in energy efficiency. It is by building conditioned crawlspaces that we are able to achieve ‘Energy Star” ratings on our homes.

Although the construction cost are greater, building a home with a conditioned crawlspace is something that should be done. It is worth the extra cost for many reasons and it will benefit the homeowner for years to come.

Stay tuned to our blog updates for more insight into how we build our homes.