Why does my basement floor always feel so cold?

Most houses built with basements in the last few years will have an insulated floor slab and this helps a lot in terms of creating a warmer feeling floor. However, if your home was built before about 2005 there is a good chance the slab is resting on gravel which is in direct contact with soil having a constant temperature of about 50°F (10℃).  As a result, the floor will feel “cold” (the proper phrase is “less warm”) because it is a lower temperature than your body.

To understand why that is significant, let’s think about basic physics in relation to heat transfer. It is a fact that heat naturally moves from warm to less warm and there are only 3 types of heat transfer;

Convective (warm air rises. Think of a warm air balloon)

Radiant (think of the heat from a fire)

Conductive (think of touching a hot element on the stove)

So, comparatively, the slab, being at a lower temperature than your feet, draws the heat from your feet which your brain senses and identifies as being uncomfortable or “cold”. The longer you stand on the floor, the more the heat will transfer from you to the slab and make you feel less and less warm and more and more uncomfortable.

Our bodies generate heat and just like any other heat source, we radiate heat energy as it gets absorbed by anything lower in temperature than our body such as the air, furnishings, wall surfaces and unheated floors. There really is no practical way to completely eliminate this type of heat transfer but it can be reduced significantly by raising the surface temperature of the biggest “heat magnet” in the room which is the floor and that’s where ventgrid12 can help.

Ventgrid12 provides a thermal break between the floor finish and the less warm concrete slab by creating an air space between the two surfaces. ventgrid12 practically eliminates conductive heat transfer much the same way a double pane thermal window reduces heat loss versus a single pain.
So, the longer you continue to stand on the floor in bare feet, the more you’ll feel “cold” because the heat is being transferred out of your body right through your feet.

So, how does “R –value” play a role in keeping my floor warmer?

The term R-value as it relates to insulation is often misunderstood. The definition of R value is – The measured resistance of a material to transfer heat energy.

If we think about the 3 types of heat transfer, which ones affect the temperature of a floor? Well, it’s obviously not convective so radiant heat loss is a factor as is conductive but conductive is the one we feel the most. Again, to use an analogy, think of the hot element on the stove; what would lead to a painful burn faster; holding your hand close to the element or ON it? The answer is painfully obvious.

When it comes to insulating a floor from conductive heat transfer, all that is needed is to create a gap, or in technical terms; a “thermal break”, to stop the flow of heat from your feet to the slab beneath. Still not convinced? Well, try this little experiment;
Save up a bunch (dozen or so) water bottle caps. Place them together side by side on the floor flat side up covering an area roughly the same size as your foot. Then stand on top of them and feel the difference from standing flat on the concrete. No insulation in a bottle cap but the difference is noticeable. Why? Because a thermal break was created between the concrete and your foot almost eliminating the heat transfer; Simple logic really.

So why do people think we have to put rigid foam insulation on top of our floor to make it feel warm? Because they just don’t understand heat transfer and there are companies who like to sell rigid insulation. But now you know better and you should also know that ventgrid12 will work as a perfect insulator from conductive heat loss; the only real heat loss that makes us feel cold standing on our basement floor.

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