Insulation Below Radiant Floor Concrete Above Grade

Confirm with your engineer what strength is needed.

Insulation below radiant floor concrete above grade.

For a vapor barrier below a concrete floor slab most choose 6 to 10 mil polyethylene. This article explains how to avoid some fatal mistakes when installing radiant heat in a concrete floor slab by describing an incompetent radiant heat floor installation along with an explanation of why things went wrong and how to avoid these errors. Why insulate under a slab on grade foundation. For example installing a below grade insulation rated for 100 psi when only 40 psi is needed will nearly double the material cost.

Their researchers found that xps insulation installed below grade for 15 years had absorbed 67 percent or more moisture. Insulation below the slab suits continuous low level heating gradually warming the thermal mass of the concrete and sustaining it at a consistent temperature. Because extruded polystyrene insulating board will absorb little moisture the vapor barrier can be placed above or below the slab insulation. Slab on grade floors with a floor surface less than 12 inches below grade should be insulated in accordance with information provided in the insulation and fenestration requirements by component table which is reproduced following this paragraph.

For crete heat below grade installations will require a vapor barrier. The greater the temperature differential between the floor and the ground below the greater the rate of heat loss will be. 2015 iecc irc section r402 2 10 n1102 2 10 slab on grade floors. Where the heating is likely to be turned on and off such as in new build domestic properties and a faster thermal response is required the floating floor arrangement of insulation above the slab can be more appropriate.

For comfort and to save money that s why. For your above grade floors some heat will be lost downwards but this is not a problem as it will simply be adding heat to the room below. Radiant heating system design or installation mistakes that must be avoided. On or above grade installations may or may not require a barrier depending on the flooring type and local codes.

One of the best ways to save money on rigid foam insulation installed under concrete slabs is to ensure the material is not over engineered. Although building codes differ by region builders typically use r5 and r10 insulation under the concrete slab but floors insulated with r20 contain the heat in your basement far better than those insulated with lower r values. In many areas building code has fallen behind common sense on what specification of insulation to use under a slab it is common to install as little as r5 insulation below slab floors making that about the weakest point in a building envelope as walls are. Can blanket insulation be used together with on top of or under foamboard insulation.

Insulating below slab on grade foundations. Many designers mistakenly assume that loads placed on slabs transfer through to the underlying insulation and soil at a 45 degree angle instead of a more uniform distribution. Target an appropriate compressive strength. In most cases rfoil concrete insulation can be used in conjunction with rigid foamboard but only when installed on top of foamboard.