Insulation Type | R-0 | R-5 | R-10 | R-15 | R-20 | R-30 |
| | | Unheated Slab | | |
Uninsulated slab | 0.73 | — | — | — | — | — |
2 ft. Horizontal (No thermal break) | — | 0.70 | 0.70 | 0.69 | — | — |
4 ft. Horizontal (No thermal break) | — | 0.67 | 0.64 | 0.63 | — | — |
2 ft. Vertical | — | 0.58 | 0.54 | 0.52 | — | — |
4 ft. Vertical | — | 0.54 | 0.48 | 0.45 | — | — |
Fully insulated slab* | — | — | 0.36 | 0.31 | 0.26 | 0.21 |
| | | Heated Slab | | |
Uninsulated slab | 0.84 | — | — | — | — | — |
Fully insulated slab* | — | 0.74 | 0.55 | 0.44 | 0.39 | 0.32 |
R-5 Center (With perimeter insulation) | — | — | 0.66 | 0.62 | — | — |
R-10 Center (With perimeter insulation) | — | — | — | 0.51 | — | — |
3 ft. Vertical | — | — | 0.78 | — | — | — |
* | Edge insulation R-10 regardless of the below slab insulation level. |