How Thick Insulation For Concrete Floor

80 of the heat is lost through 20 of the total surface.

How thick insulation for concrete floor.

If you have enough clearance in the basement to add a few inches of height to the floor one of the most effective ways to insulate the floor is to first install a sheet of polyethylene as a vapor barrier over the concrete extending it about three inches up the walls. Room alterations you will need to think about raising skirting boards trimming doors and maybe moving sockets. Not a finished surface you will need to lay a chipboard layer over the insulation boards adding to the height. Thickness many types of insulation board are at least 50mm thick raising the level of the floor.

A 50mm thick layer of proprietary floor slab insulation is usually enough to reach and maintain the target u value but this should be checked with an architect first. It is preferable to cover the area being worked on with just one large sheet but in cases where more than one sheet is required joins should overlap by at least 150mm and be sealed to prevent any moisture coming up through the new concrete slab. Why is this the case. Designers generally insulate both directly under the slab and around the perimeter as well.

Lightweight rigid polyisocyanurate pir foam insulation boards such as those manufactured by celotex are among the most thermally efficient commonly available. The insulation is then laid followed by a polythene separating layer and either a concrete screed or tongue and groove chipboard ready to receive the specified floor finish. In cold climates it is advisable to use a minimum of 2 inches of extruded polystyrene under the slab. There are two main reasons that i know of.

The first important thing to pay intention to is the depth of the floor slab. Namely if you are only digging the slab you will need to take into account the thickness of the insulation since it will affect the depth of the slab. It s the old pareto 80 20 rule with concrete floors. Many increase the under slab insulating foam board thickness to 3 or 4 inches at the outer 2 to 4 feet of the slab.

The math is pretty simple the thicker the concrete floor insulation material the deeper the slab will have. Step 4 place 2 inch thick pieces of rigid styrofoam insulation on top of the plastic sheeting. The plastic serves as a vapor barrier preventing moisture from passing up through the gravel to the concrete floor above.