If you are building a new home or a significant addition, you will likely find yourself considering various options to insulate the exterior walls and attic. Each option has a stated “R Value” which measures the resistance to heat loss. The higher the R Value the better, however, you should be comparing the whole wall R Value, which incorporates all of the other materials composing your exterior wall, for instance, the wood framing and sheathing. Following are approximate values for the most common exterior wall systems:
- 2 x 4 wood studs @ 16” o.c., with R13 fiberglass blanket insulation at cavities, ½” wood sheathing, house wrap: R-10
- 2 x 6 wood studs @ 16” o.c., with R19 fiberglass blanket insulation at cavities, ½” wood sheathing, house wrap: R-13.7
- 2 x 4 wood studs @ 16” o.c., with R-13 fiberglass blanket insulation at cavities, ½” wood sheathing, and 1” Extruded Polystyrene continuous outside sheathing: R-15.
- 2 x 6 wood studs @ 24” o.c., with open cell spray foam insulation at cavities, ½” wood sheathing, house wrap: R-16
- 2 x 6 wood studs @ 24” o.c., with R-19 fiberglass blanket insulation at cavities, ½” wood sheathing, and 1” Extruded Polystyrene continuous outside sheathing: R-20
- 2 x 6 wood studs @ 24” o.c., with closed cell spray foam insulation at cavities, ½” wood sheathing, house wrap: R-20
- 9” Insulated Concrete Forms with 5” Expanded Polystyrene: R-20
View our completed Neoclassical home in Clarence NY, insulated with 2″ continuous rigid foam.
