How Thick Insulation For Concrete Floor

Many increase the under slab insulating foam board thickness to 3 or 4 inches at the outer 2 to 4 feet of the slab.

How thick insulation for concrete floor.

Why is this the case. The first important thing to pay intention to is the depth of the floor slab. Insulation sheets should be laid tightly together with the joints staggered to avoid movement. 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.

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. 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. 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.

Lightweight rigid polyisocyanurate pir foam insulation boards such as those manufactured by celotex are among the most thermally efficient commonly available. Designers generally insulate both directly under the slab and around the perimeter as well. Step 4 place 2 inch thick pieces of rigid styrofoam insulation on top of the plastic sheeting. 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.

Room alterations you will need to think about raising skirting boards trimming doors and maybe moving sockets. Thicknesses of dpms vary but 1 200 gauge is a common thickness. Place the insulation edge to edge using duct or other construction tape to hold the insulation together. 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.

The plastic serves as a vapor barrier preventing moisture from passing up through the gravel to the concrete floor above. It s the old pareto 80 20 rule with concrete floors. There are two main reasons that i know of.