Cold floors are one of the most common complaints amongst Indianapolis, IN, homeowners, with open crawl spaces. This air can make the floors icy cold and uncomfortable. So, what is making the floors above their crawl spaces cold?
During winter, the cold outdoor air enters the crawl space through vents and gaps in the structure. The cold air travels from your crawl space and into the rest of the house through the stack effect.

What Is the Stack Effect?
The stack effect is the movement of air due to thermal differences. Naturally, warm air is less dense than cool air. When cold air enters your crawl space through vents and gaps in the foundation walls, it pushes the warm air out of the house before infiltrating your home. As a result, your home cools down and becomes colder. This explains why floors, walls, and surfaces feel cold.
Other than pushing in cold air, the stack effect also allows mold spores, dust mites, and nasty odors to travel to your living space, contaminating the air that you breathe. To keep your crawl space dry and healthy, you must maintain optimal indoor humidity and temperatures. Just like you ensure that moisture does not enter your crawl space, it is also crucial to prevent unwanted outdoor air and drafts from entering your home to cause energy loss.
Curbing Crawl Space Cold
These three solutions can help you beat back the cold that’s infiltrating your home through the crawl space.
Closing off vents
While codes encourage homeowners to vent their crawl spaces, recent studies show that these fixtures are better off sealed. Seal off the crawl space vents with durable plastic vent covers. Blocking vents ensures your crawl space stays warm. Best of all, it also enhances the effectiveness of your furnace, heating ducts, water heater, and hot water pipes.
Crawl space insulation
According to the U.S. Department of Energy, a properly insulated crawl space, in addition to air sealing, equals a more comfortable and energy-efficient home. You can make the cold crawl space part of the warm side of your home by doing these.
- Seal and insulate hatchways. If your crawl space has a hatchway, it must be air stripped or fitted with an airtight entry system. Make sure you seal all gaps along the rim joists.
- Seal and insulate ducts. Most crawl spaces have air ducts and plumbing pipes running between the joists. Since these ducts connect to the air system in the entire house, they should not have any holes or leaks. A damaged air duct allows conditioned air within the house to escape to the outdoors, leading to a colder home. It also allows unwanted air from within the crawl space to move up into your home. You can solve this problem by air sealing and insulating all of the supply and return ducts in the crawl space.
- Seal and insulate plumbing. Your water pipes need some TLC. By insulating them, you’ll prevent frozen pipes and potential leaks and floods due to burst pipes in winter.
- Use other effective insulation materials. Typical fiberglass insulation can easily get wet and fail to work effectively. Instead, have rigid insulation panels placed on your crawl space walls. Additionally, spray foam insulation also can be used along rim joists.
Crawl space Encapsulation
Once you have insulated your crawl space, the next important step is to encapsulate it with a heavy-duty, 20-mil vapor barrier liner. The plastic barriers go over the unfinished crawl space floor and up the walls, then taped down to the seams. What this does is isolate the crawl space by turning it into a conditioned (heated and cooled) area in your home. Temperatures down there will match those of your home, meaning floors and walls above it will stay warm in winter. Encapsulation locks out cold, wet air and pests.
Don’t let the crawl space cold dampen your mood and cause you sleepless nights this winter. Get in touch with our crawl space encapsulation experts at Indiana Foundation Service. We will provide you with a free crawl space waterproofing inspection and quote along with recommendations to keep this space dry, clean, and mold-free. Your home will stay warm and comfortable all year round, not just in winter!