Garage door R-value by construction
A garage door’s insulation value depends on its construction: a 1-layer door is a bare steel skin (little R-value), a 2-layer adds polystyrene, and a 3-layer sandwiches polyurethane foam between two steel skins (the highest R-value, strongest and quietest). The bands below are labeled planning bands — manufacturers measure R-value differently, so confirm on the door’s spec sheet. Use them with the R-value helper and insulation cost tools.
| Construction | Typical R-value band |
|---|---|
| 1-layer (single steel skin, no insulation) | R0–6 |
| 2-layer (steel + polystyrene) | R6–9 |
| 3-layer (steel + polyurethane + steel) | R9–19 |
Labeled planning bands. Manufacturers measure R-value differently, so compare on the door’s own spec sheet. A higher R-value door is also stronger and quieter.