Why Are My Floors Cold?

No one likes walking on cold floors. If you don’t have a layer of socks or house slippers to form a barrier, the floor seems to leech the heat right out of your body. Why are the floors in your home so cold? What can be done to make your floors warmer?

South Central Services has insulated hundreds of new and existing homes with spray foam. Greencastle, Pennsylvania and the surrounding towns have some cold winters! Cold floors are almost always an indication of poor insulation. There are solutions to make your floors warmer and more comfortable to walk on. However, you want to select the right insulation to solve the cold floor problem.

By the end of this article, you will understand:

• Why cold floors are an insulation issue
• How cold air travels in your home
• Which insulations can stop cold air
• Where to insulate to prevent cold air transfer

Don't have time to read right now? Check out everything you need to know at a glance.

Cold Floors Indicate Insufficient Insulation.

Your home’s thermal envelope needs excellent insulation. The thermal envelope is the barrier between your conditioned home environment and outside temperatures.

Generally, a home’s thermal envelope is made up of the attic, exterior walls, basement, and crawl space. Not every home has a basement and crawl space, but homes should have one or the other.

If the thermal envelope doesn’t have enough insulation, it is challenging for a home to keep a temperature different from the outside.

For example, attics with insufficient insulation cause problems in the summer and winter. In the summertime, heat fills the attic and presses into the rest of the home. Proper insulation in the attic would prevent hot air from invading the house.

In the winter, heat leaves through the attic as it is drawn to the cold air outside. The air that replaces this escaped heat comes from the freezing basement or crawl space. This is known as the stack effect.

Without sufficient insulation in the basement or crawl space, the air pulled from below is just as cold as the air outside.

Cold Air Travels Through Insulation Without An Airtight Seal.

What if you do have insulation in your thermal envelope? Maybe your attic has some fiberglass batts in the floor, or your crawl space has some batts in the ceiling. If you have insulation, how are your floors still cold?

The key difference here is the performance of different insulation products. Fiberglass batts are considered a suitable insulation product based on their R-value, or resistance value. Since the fiberglass material is resistant to conductive heat transfer, it is often installed in these critical areas of the home.

However, fiberglass batts do not stop air transfer. Fiberglass insulation allows air to pass through it, slowing heat transfer. But heat can also be transferred through the air via convection and radiation. Fiberglass batts are defenseless against two of the three methods of heat transfer.

Without an airtight seal in your thermal envelope, air and heat can still exchange. Cold air can still travel to your floors. Having sufficient insulation in your thermal envelope refers to a high R-value and an airtight seal.

If Cold Air Can Reach Your Floors, Your Floors Will Be Cold.

Think about the state of the insulation beneath your floors. Do you have any insulation below? Is the insulation falling from the cavities it was stuffed into?

If your floors are cold, you may have a crawl space that needs to be dealt with. Crawl spaces are notorious for letting cold and dirty air into living spaces. Or, you may have basement rim joists with little to no insulation.

Crawl Spaces Contribute Significant Cold Air Infiltration.

Not every home has a crawl space. However, if your home has a crawl space, understanding how air travels through your crawl space is in your best interest.

The standard crawl space is open to air exchange through vents. These vented crawl spaces allow air from outside to flow and circulate. In the winter, this air will be cold. The only barrier between the cold crawl space air and your floors is often some fiberglass batt insulation. If you’re lucky, the batts are still inside the ceiling cavities. More likely, however, your fiberglass is dripping from the ceiling and letting all that cold air inside.

There are two main solutions for crawl spaces. You can put an airtight seal in the crawl space ceiling or encapsulate the crawl space. Which solution is right for you depends on a few factors. However, the goal is to cut off the cold air from either your living space or both the living and crawl spaces.

Basement Rim Joists Allow Cold Air To Infiltrate.

Rim joists are the meeting place of your basement walls and basement ceiling. Basement rim joists are also the transition between porous masonry walls and wood floor joists. This material transition makes the rim joists more susceptible to cold air infiltration.

Most rim joists need to be better insulated. At most, they may have some fiberglass batts stuffed inside. However, as previously discussed, fiberglass doesn’t stop air infiltration. Basement rim joists need an airtight seal.

We recommend closed cell spray foam insulation for rim joists. This product provides a high R-value, an air barrier, and a vapor barrier for any vapor transfer concerns. By sealing off these rim joists, cold air cannot reach the basement, let alone your floors. An airtight seal in the rim joist can also cut off a route for pest infestations in your home.

The Bottom Line About Why Your Floors Are So Cold

Cold floors mean cold air. If cold air reaches your floors, your thermal envelope lacks sufficient insulation. Many thermal envelopes only have fiberglass batt insulation. Fiberglass is a popular choice for most applications. However, fiberglass cannot stop cold air infiltration.

If you want to make your floors more comfortable, you need an airtight seal in the place where cold air is leaking inside. In your thermal envelope, these areas are your crawl space or your basement rim joists. Depending on the construction of your home, you may need closed cell spray foam in one of these areas.

Now that you know why your floors are cold, your next step is to:

• Compare crawl space encapsulation and ceiling insulation
• Discover the benefits of rim joist insulation
• Learn why fiberglass insulation doesn’t belong in your crawl space