Rigid Insulation For Slab On Grade

This insulation aligns with rigid foam sheathing that covers the framed walls above grade.

Rigid insulation for slab on grade.

Two common rigid foam insulations specified for below grade applications are expanded polystyrene eps and extruded polystyrene xps. 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. When building a slab on grade eps rigid foam insulation is the most common choice of insulation for performance and cost. An easy way to recognize eps on the jobsite is that it is commonly white.

Figure 4 11 illustrates a slab on grade foundation with a masonry foundation wall. I wouldn t go as far as saying you couldn t use spray foam below a slab but i m not sure why you d want to. It also discusses installation procedures for below grade and under slab insulation. R 7 7 rigid foam insulation model 310891 18 35 18 35.

The f factors for slab on grade floors are defined in standard 90 1. Water resistant rigid board for under concrete slab insulation and slab support in traffic bearing applications. If the slab has hydronic tubing the minimum r value of this insulation increases to r 15. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the building materials department.

Rigid insulation is placed vertically on the exterior face of the foundation wall. Continuous insulation is defined in 90 1 as insulation that is continuous across all structural members without thermal bridges other than fasteners and service. Spray foam for sure has uses where it is the best choice by a long shot but under a slab is not the place. While standard building codes typically require insulating value ranging from r 10 to r 15 detailing around the perimeter is generally weak.

Slab is one foot or less below grade r 10 insulation required extending 2 feet below grade for climate zones 4 and 5 4 feet below grade for climate zone 6 insulation should extend downward from the top of the slab with two options to reduce slab edge insulation r value exterior slab insulation must be protected 46. These f factors are acceptable for all slab on grade floors but you need to make sure. This may leave a significant thermal. Materials suitable for below grade insulation are limited to rigid foam high density spray foam and rockwool boards.

Insulating a slab on grade can be expensive. Below grade to have r 10 vertical insulation at the slab perimeter extending downward from the top of the slab to a depth of at least 2 ft. 2015 iecc irc section r402 2 10 n1102 2 10 slab on grade floors. Set your store to see local availability add to cart.

Below grade under slab with foamular xps insulation.