Compressed Attic Insulation

What is attic insulation.

Compressed attic insulation. When it s time to re roof adding 2 of roofing polyiso or a 2 5 polyiso nailbase panel would be sufficient to beat code minimum performance on a u factor basis due to the r11 thermal break over the rafters. Batt and roll insulation works well between joist and stud spaces or if you have a wide open space or a crawlspace. Make sure your home is properly insulated in all these locations. This lowers the insulation s r value.

Insulation loses its effectiveness when it is constantly being compressed by being walked on or having boxes stored on it loses its insulation ability. There was no plywood up there plus it looks like the insulation is not uniformly compressed. Subtract the cavity depth from the thickness of the batt in inches. Grab a tape measure and a flashlight to see what kind of insulation you already have in the attic and how deep it is.

Yes the compressed r value can be estimated using the following method. Batt and roll insulation and loose fill sometimes known as blown in insulation. When compressed to less than its labeled thickness glass fi ber insulation will experience a reduction in r value. R value simply means resistance to heat flow.

Achieving greater r values in attics. Let s look at an r 19 batt in a 2x6 cavity step 1. These thermal defects undermine the r value of your attic insulation. The floor insulation can simply be left in place if you re now heating the attic.

See install batt and roll insulation for details. The chart below indicates the compressed r value of standard building insulation products when installed in framing cavities with a depth that is less than the labeled thickness of the insulation. There are two main types of insulation. You can mix the type and material of insulation too.

Insulation ratings can be improved by adding more layers of insulation. Then use the numbers in the chart at right to estimate its r value. There is a path down the center of the attic that has the top 6 inches of insulation above the joists that appears to have been compressed by either some one crawling across the attic or laying a piece of plywood across the joists. Loose fill blown in insulation is best for tight spaces or if your attic already has a layer of insulation.

I have a question for you regarding what you wrote. To make a niche i want to compress the insulation quite a bit down to only 1 5 or 1 75 inches. The ideal attic insulation r value is different than the ideal wall insulation r value. Over the years fiberglass batt insulation gradually collapses and deteriorates.

I believe it is r 19. Pull up and dispose of any material that s compressed water stained or moldy it s useless.