rigid insulation r value
Charlotte Adams
Updated on August 17, 2026
With an R-value of 13.1 for a 2″ thick sheet only two 2″ sheets are required to achieve R-25. 2. Extruded polystyrene or XPS (foam is usually pink or blue) XPS has an R-value of 5 per inch of thickness requiring 5″ of insulation to achieve R-25.
What is the R-value of 1 inch foam board?
The polystyrene is expanded. Styrofoam insulation is the cheapest material. R-values can range from 3.6 to 4.2 per inch.
What is the R-value of 3 inch Styrofoam?
Expanded Polystyrene Foam
This product typically has an R value of 3.6 to 4.0 per inch of thickness.
How thick is r30 rigid insulation?
Typical R-30 fiberglass insulation is 10-inches-thick. Prior to buying fiberglass insulation, it is important to measure the joint spacing you are working with. Note that the actual space between the framing members will be less than 16 or 24 inches, but the foam batts can easily be stuffed between these lengths.
What is the thinnest insulation with the highest R-value?
Aerogel insulation offers the highest R-value of any insulating material at less weight and thickness—ideal for construction, refineries, pipelines, and thin-gap thermal barriers.
What is the difference between pink and blue foam board?
Both are manufactured using the same process and contain similar chemical components. The two products also have the same insulating power. However, blue foam boards are manufactured by Dow Chemical Co. whereas the pink foam boards are manufactured by Owens Corning company.
What insulation has the highest R-value per inch?
Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch; aerogel has the next highest R-value (about R-10 to R-30 per inch), followed by polyurethane (PUR) and phenolic foam insulations with R-7 per inch.
What is the R-value of Rockwool?
While fiberglass insulation is capable of offering an R-value of about 2.2 to 2.7 per inch of insulation, Rockwool has an R-value between 3.0 to 3.3 per inch of insulation.
What is the R-value of XPS insulation?
XPS Data Summary:
R-value: 4.7 per inch.
What is the R-value of 6 inch styrofoam?
One common use of extruded polystyrene foam board is for foundation insulation panels. Polyiso (Polyisocyanurate). This is an even more dense and more expensive foam board insulation. It provides an R-value of 6 per inch of thickness and often comes foil-faced to help reflect radiant heat.
What is the R-value of foil board?
Attached to the face of studs, FOILBOARD® INSULATION PANEL eliminates thermal bridging through the frame and air infiltration. Without insulation a cavity brick wall has an ‘R’ value of 0.5. FOILBOARD® INSULATION PANEL in the cavity will achieve R1. 8 with STANDARD 10 and R2.
What is the R-value of Dow blue board?
DuPont™ STYROFOAM™ Scoreboard Insulation Board (Blue Board) 4 ft by 8 ft Sheet, 1.5″ Thick, R value 7.5 A nonstructural, rigid board insulation manufactured of Extruded Polystyrene Foam (XPS).
What is the R-value of spray foam in a 2×4 wall?
Open-cell spray foam absorbs and holds water. It has a lower R-value per inch than closed-cell foam and is vapor-permeable. The R-value is R-3.5 to R-3.6 per inch, so filling a 2×4 cavity yields about an R-13.
Does foam board insulation need a vapor barrier?
Foam insulation usually does not require a vapor barrier. For some foam insulation types, such as closed-cell spray foam and foam board insulation, the insulation itself stops the movement of most water vapor.
What is the R-value of a 2×6 wall?
When blown or sprayed cellulose insulation is used, the R-value is typically R-20 for 2×6 walls.
What is the difference between R30 and R19 insulation?
The bigger the R value, the better the insulation is at slowing down the heat transfer. So R19 is better insulation than R13, and R30 is better than R19. The larger the R value, the better the insulation value.
Is foam board a good insulator?
Foam board insulation provides good thermal resistance and reduce heat conduction through structural elements, such as wood and steel studs, according to the U.S. DOE.
What is the R-value of 2 inch blue Styrofoam?
A wall utilizing STYROFOAM T-MASS Technology with a 2-inch exterior layer and a 4-inch interior layer of concrete along with a 2-inch layer of STYROFOAM extruded polystyrene insulation would result in a material R-value of approximately 11.33.