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What is the R-value of wood?

Author

Sophia Vance

Published Jan 11, 2026

The R-Value of Wood

The R-value for wood ranges between 1.41 per inch (2.54 cm) for most softwoods and 0.71 for most hardwoods.

What is the R-value of 4 inch thick wood?

The R-value of softwoods ranges from 1.41 per inch for most softwoods to 0.71 for hardwoods. So, if you have an exterior wall made of 4-inch-thick wood, it might have an R-value somewhere in the range of 3 to 6.

Is wood a good insulator of cold?

Wood exhibits a low thermal conductivity (high heat-insulating capacity) compared with materials such as metals, marble, glass, and concrete. Thermal conductivity is highest in the axial direction and increases with density and moisture content; thus, light, dry woods are better insulators.

What is the R-value of 1 inch of pine wood?

In a solid log wall, the logs provide both structure and insulation. The R-value for wood ranges between 1.41 per inch (2.54 cm) for most softwoods and 0.71 for most hardwoods.

What type of wood has the best insulation?

The nanowood insulated better in both cases. The wood blocked at least 10 degrees more heat than styrofoam or silica aerogel, which had been awarded the Guinness World Record for 'best insulator'. The nanowood, which is white, also effectively reflects sunlight.

This Swiss Builder uses NO INSULATION...

Does drywall have any R-value?

Drywall, for instance, has an R-value of about R-0.5 for its half-inch thickness. This is minimal when you consider that filling a 4-inch-thick wall cavity with insulation increases the R-value to about R-15.

What is the R-value of 1 inch Styrofoam?

STYROFOAM extruded polystyrene insulation is rated at an R-value of 5.0 per inch at 75°F.

What is the R-value of OSB?

OSB (½-inch) has an R-value of 0.5 – 0.62. Fiberboard is less expensive than OSB.

What is the R-value of a 2x6 board?

Thermal Control

The installed insulation R-value for 2x6 fiberglass batt ranges between R-19 and R-21. When blown or sprayed cellulose insulation is used, the R-value is typically R-20 for 2x6 walls.

Does concrete have an R-value?

Concrete has a low R-value. Concrete by itself has a very low R-value, a measure of thermal resistance. Its insulation value comes primarily from using it in thick slabs, and hence isolating the insulated space from thermal fluxes in the environment.

What is the R-value of metal?

The r-value, which is also called the Lankford coefficient or the plastic strain ratio, is the ratio of the true width strain to the true thickness strain at a particular value of length strain, indicated in Equation 1. Strains of 15% to 20% are commonly used for determining the r-value of low carbon sheet steel.

What is the R-value of a 2x10?

The rafters in cathedral ceilings are usually made of 2x12s or 2x10s, and Owens Corning makes two special high-density insulation products specifically for these rafters -- R-38C for 2x12s and R-30C for 2x10s.

Whats the highest R-value you can get in a 2x4 wall?

They are available in widths suited to standard spacings of wall studs and attic or floor joists: 2x4 walls can hold R-13 or R-15 batts; 2x6 walls can have R-19 or R-21 products.

Does plywood act as insulation?

Plywood is one insulation option. The R-value is a measure of how effective a material is as an insulator, i.e. how well it keeps cold air out of a warm building, or hot air out of a cold building.

What is the R-value of aluminum foil?

According to ASHRAE, when just a little condensation is visible on aluminum foil, the emissivity can reach 0.2 to 0.3, which would decrease that R-value down to R-3.86.

What is the R-value of metal studs?

The correction factors account for thermal inefficiencies every 16” or 24,” based on steel studs with an R-value of roughly 0.1 per inch.

What is the R-value of 2 foam board?

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.

Does cinder block have an R-value?

Cinder block walls have an extremely low R-value, ranging between 1.9 and 2.5. The recommended value for an exterior wall is between R-13 and R-23. Therefore, a cinder block wall, without any additional material, has very little insulating properties.

What is a good R-value?

Depending on where you live and the part of your home you're insulating (walls, crawlspace, attic, etc.), you'll need a different R-Value. Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces.

What is the R-value of rigid foam board?

Extruded polystyrene: Extruded polystyrene (XPS) rigid foam is usually blue or pink in color, with a smooth plastic surface. XPS panels typically aren't faced with other material. The R-value is about R-5.

Can wood be used as insulation?

Wood and wood-base materials are by nature relatively good heat insulators. The natural fiber of wood is in itself a hollow cell which provides a minute air space, hence an insulating unit.