Insulating Value of Terracotta & Concrete Floor Structures

Insulation

• The purpose of an insulating material is to prevent the conductivity of heat or cold. The less conductivity, the less heat or cold that is transferred. Those materials then, that are poor thermal conductors, can make good insulators. Materials such as cotton wool, fiberglass, or corkboard are terrible thermal conductors; the amount of any heat they conduct averages around .043, which is almost no thermal conducting at all. Copper and gold transfer a tremendous amount of heat at about 400 units each, which is why these are used for wiring and thermal connectors in machinery. This high conductivity rate suggests that gold, silver or copper offer no resistance to heat movement. Concrete is somewhere in the middle, with the highest quality Portland Cement about .29, similar to the insulating properties of snow. Wood is about .17. Dried clay, which makes terra cotta, is about .15 or lower.

Terra Cotta

• Dried clay that is deliberately designed to act as housing material will be the highest insulating quality possible, far lower than the .15 of normal dried clay. Dried clay made into terra cotta materials is an excellent insulating material, both for cold and heat. Because terra cotta is porous, it will still permit moisture to escape, much like “breathing” cotton.

Concrete

• The highest quality Portland cement is impressive, but still inferior to dried clay. However, a type of insulating concrete contains the rock perlite, which is added to the concrete mixture at about a 1:5 ratio. Not only does it help with insulation, but it makes the concrete itself weigh less and easier to work with.

Perlite Concrete

• According to the Perlite Institute in Harrisburg, Pennsylvania, concrete treated with perlite has about half the insulating properties as the highest quality fiberglass insulating panel. Hence, 2 inches of this concrete will be the same as 1 inch of the highest quality fiberglass board. The benefit here is that, using 2 inches of perlite-treated concrete is a structural material, unlike fiberglass boards, that will eliminate the need to add insulation at all. A heavy treatment of perlite will make the concrete about 20 times as insulating as regular concrete. Perlite is one of the most insulating materials on the globe, rated about .00137. This is an almost non-existent amount of thermal conductivity.