What R-value should a Knoxville attic have?

R-38 is the common minimum and R-49 is the recommended target for East Tennessee attics.

Can I add insulation over old insulation?

Yes, as long as the existing material is dry and not compacted. Wet or moldy insulation needs to come out first.

Material Calculators

East Tennessee attics generally target R-38 to R-49. Enter the area and target R-value to size the material.

Your numbers

Area length(ft)

Area width(ft)

Insulation type

Target R-value

Bags of blown-in

30 bags

Air-seal top plates, can lights, and the attic hatch before adding insulation — sealing first is what makes the R-value actually perform.

Quantities are planning estimates. Verify measurements on site and buy a little extra for cuts, waste, and future repairs.

Gallons of paint and primer for a room, based on real wall area.

Sheets, screws, joint compound, and tape for walls and ceilings.

Tile count, thinset, and grout for a floor, shower, or backsplash.

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