Rigid Insulation For Slab On Grade

In climate zones 4 and 5 the code requires certain slabs below grade slabs that are less than 12 in.

Rigid insulation for slab on grade.

Two common rigid foam insulations specified for below grade applications are expanded polystyrene eps and extruded polystyrene xps. R 7 7 rigid foam insulation model 310891 18 35 18 35. Consult appendix a table a6 3 1 in the 2016 edition for a tabulation of assembly f factors for slab on grade floors based on the arrangement and rated r value of the applied insulation. Below grade under slab with foamular xps insulation.

It also discusses installation procedures for below grade and under slab insulation. 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. If the slab has hydronic tubing the minimum r value of this insulation increases to r 15. 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.

Water resistant rigid board for under concrete slab insulation and slab support in traffic bearing applications. Set your store to see local availability add to cart. 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. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the building materials department.

While standard building codes typically require insulating value ranging from r 10 to r 15 detailing around the perimeter is generally weak. Rigid insulation is placed vertically on the exterior face of the foundation wall. The f factors for slab on grade floors are defined in standard 90 1. Spray foam for sure has uses where it is the best choice by a long shot but under a slab is not the place.

These f factors are acceptable for all slab on grade floors but you need to make sure. When building a slab on grade eps rigid foam insulation is the most common choice of insulation for performance and cost. Insulating a slab on grade can be expensive. 2015 iecc irc section r402 2 10 n1102 2 10 slab on grade floors.

Continuous insulation is defined in 90 1 as insulation that is continuous across all structural members without thermal bridges other than fasteners and service. This insulation aligns with rigid foam sheathing that covers the framed walls above grade. Figure 4 11 illustrates a slab on grade foundation with a masonry foundation wall. This may leave a significant thermal.

Materials suitable for below grade insulation are limited to rigid foam high density spray foam and rockwool boards.