STYROFOAM™ brand rigid insulation is available in multiple thicknesses, most commonly 1”, 2”, and 3”, with different densities and corresponding R-values depending on the application. Additional thicknesses can be achieved by combining multiple layers of standard board thicknesses and alternating the seams.
It is widely used in residential construction for below-grade foundation insulation, under-slab insulation, and exterior foundation protection.
Overall, STYROFOAM™ insulation is a versatile rigid foam product used throughout residential construction to improve energy efficiency, manage moisture, and protect foundation systems.
Thickness Options & Uses
| Thickness | R-Value | Primary Use | Key Benefits |
|---|---|---|---|
1" |
R-5 |
Below-grade foundation walls (inside or outside) |
Reduces moisture infiltration, helps retain interior heat, provides basic foundation insulation |
2" |
R-10 |
Under residential concrete slabs (especially hydronic heated slabs) |
Prevents heat loss into the ground, improves heating efficiency and comfort |
3" |
R-15 |
Foundation wall protection during backfill |
Higher insulation value, impact resistance, moisture barrier, reduces freezing-related cracking and interior condensation |
