Rigid foam insulation is a versatile product that is resistant to mold and moisture, making it ideal for under-floor applications. Rigid foam is manufactured in sheets that are 2-by-8 feet in size and 1- or 2-inches thick.
The thicker the foam, the better insulation it will provide for your floor. If your tile floor is on the ground floor of a house that is built on pillars, or a house with a very cold basement, you can cut down on the influx of cold air through your floor by fitting rigid foam in between the floor joists underneath the tile floor.
Many houses are now built with in-floor heating. This type of heating features pipes that are set within a concrete slab in the floor.
The pipes circulate warm water and the heat from the water is transferred to the floor, which passively warms the room. This type of floor-based heating system is often used in conjunction with tile floors.
By insulating underneath the concrete slab, you can help send the heat from the slab up into the house rather than down into the ground. This type of insulation is done with a special type of rigid foam that is strong enough to resist the weight of the concrete on top of it.
A lot of the cold that you feel coming up through your floor may be filtering in from the outside walls of your house. Particularly in older homes, the spaces between floor joists in the basement are often poorly insulated.
Cold air enters through the walls and fills the area between the joists, making the floor cold. You can block this air by fitting rigid foam panels in between the floor joists against the outside wall, then filling any gaps that are left with expanding foam.
Use insulated sub-flooring to keep a tile floor warmer if you are in the process of laying the tile floor. While the previous methods are appropriate for existing tile floors, this method can be incorporated into the floor itself as it is being built.
Put down a layer of rigid foam on top of the floor joists or the existing sub-flooring, then put down another layer of sub-flooring on top of it. The tile floor is attached to the upper layer of sub-flooring.
Be sure to fasten all layers of sub-flooring securely to the joists, so there is no movement when the tiles are attached.