How Much Roof Insulation Is Enough

For these locations i recommend intermediate insulation values between those for cold climates and hot climates.

How much roof insulation is enough. Click the button to calculate the amount of insulation in square feet and man hours wall and ceiling fiberglass insulation needed for this job. I suggest a 4 5 10 30 60 rule. Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation. As a general rule the attic needs to have 12 inches of insulation warner said.

If you need to add four inches approximately r23 with polyiso insulation or r15 with expanded poly styrene there may not be enough room between the membrane at the roof penetrations. Recommended insulation levels for retrofitting existing wood framed buildings. Add insulation to attic. Input length and width of area to be insulated.

R 4 windows r 5 under slabs r 10 foundation walls or slab perimeter r 30 above grade walls and r 60 in the attic or roof. Membrane manufacturers as well as various building codes require 8 inches of space from the flat roof membrane up to a penetration. You will need a higher r value of insulation if you live in the northeast than if you live in southern california. What about existing houses.

I suggest a 4 5 10 30 60 rule. Where you live different climates require different insulation r values. Having enough insulation in your attic is one of the best ways to save energy on both heating and cooling your home. How much insulation should you install.

The higher the r value the better job the insulation does at preventing the transfer of heat. This calculator is to be used as an estimating tool only. The amount of insulation recommended for your home will vary depending on a number of factors. R 4 windows r 5 under slabs r 10 foundation walls or slab perimeter r 30 above grade walls and r 60 in the attic or roof.

Have loose fill insulation blown in on top of existing insulation. For these locations i recommend intermediate insulation values between those for cold climates and hot climates. How well a particular insulation works is expressed by the r value which ranges from 2 0 to 8 0 per inch of insulation.