An R-value is the resistance value of particular components in construction and includes materials such as plasterboard, brick or insulation. info@celotex.co.uk 01473 820850

Mar 20, 2019 · 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. Polyiso comes in several thicknesses and is used over house sheathing underneath siding or in attic spaces where its reflective properties are very effective. Per-inch, R-value of softwood is 1.41. In hardwood, it is 0.71. Logs of around 6 inches would then have an R-value that is about 8. This value, when compared to other insulating materials, is actually pretty low; it is so low that it is below many industry standards. *R means resistance to heat flow. The higher the R-value, the greater the insulating power. R-value determined by ASTM C518. THERMAX™ Heavy Duty Insulation 1. pRoDucT nAME THERMAX™ Heavy Duty Insulation 2. MAnuf AcTuRER The Dow Chemical Company Dow Building Solutions 200 Larkin Midland, MI 48674 1-866-583-BLUE (2583) Fax 1-989-832-1465 It offers R-values from R-11 to R-70. Johns Manville’s Spider™ loose-fill insulation is blown in behind the BIBS® fabric for complete coverage, making it easier to install at R-15 and R-23 in 2×4 and 2×6 walls without bulging. The JM Spider solution does not settle, retaining its original R-value and energy efficiency. Knauf

Considering that plywood has an R-value of just 0.94, it would take a piece of plywood well over 2 inches thick to offer the same protection as a piece of fiberglass that is just 3/4 inch in width. Thus, walls would have to be excessively thick to offer fiberglass-level protection, which cuts into living space.

*R means resistance to heat flow. The higher the R-value, the greater the insulating power. R-value determined by ASTM C518. THERMAX™ Heavy Duty Insulation 1. pRoDucT nAME THERMAX™ Heavy Duty Insulation 2. MAnuf AcTuRER The Dow Chemical Company Dow Building Solutions 200 Larkin Midland, MI 48674 1-866-583-BLUE (2583) Fax 1-989-832-1465 It offers R-values from R-11 to R-70. Johns Manville’s Spider™ loose-fill insulation is blown in behind the BIBS® fabric for complete coverage, making it easier to install at R-15 and R-23 in 2×4 and 2×6 walls without bulging. The JM Spider solution does not settle, retaining its original R-value and energy efficiency. Knauf

THERMAX TM Foamboard. THERMAX TM brand insulation is a polyisocyanurate rigid board insulation with an R-value of 6.5 per inch. This product has FM 4880 class 1 wall and ceiling approval for fire exposure and can be left exposed in both the wall and ceiling providing a nice aesthetically pleasing look to the interior as well as increasing energy efficiency.

1- Per BSAF, 1#/cu.ft. eps has an r value of 3.85 AT 75 degrees F. Important for people living in the north, such as Minnesota, is that the r value at 0 degrees F is 4.55. The R Value goes up as the temperature drops. 2- The exact opposite is true for polyiso. Also it is much more expensive.