Compressed Insulation Attic

Then use the numbers in the chart at right to estimate its r value.

Compressed insulation attic.

Over the years fiberglass batt insulation gradually collapses and deteriorates. I have a question for you regarding what you wrote. Insulation loses its effectiveness when it is constantly being compressed by being walked on or having boxes stored on it loses its insulation ability. Yes the compressed r value can be estimated using the following method.

Loose fill blown in insulation is best for tight spaces or if your attic already has a layer of insulation. To make a niche i want to compress the insulation quite a bit down to only 1 5 or 1 75 inches. What is attic insulation. See install batt and roll insulation for details.

Batt and roll insulation works well between joist and stud spaces or if you have a wide open space or a crawlspace. This lowers the insulation s r value. 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. The floor insulation can simply be left in place if you re now heating the attic.

Simple thermal analysis reveals that if you have 5 missing insulation in an attic bare sheetrock you ll have a slightly more than a 54 drop in r value. R value simply means resistance to heat flow. I believe it is r 19. Most manufacturers use 40 to 60 recycled glass content.

When compressed to less than its labeled thickness glass fi ber insulation will experience a reduction in r value. You can compress fiberglass insulation as much as you want i am trying to make a shower niche on a 2x6 exterior wall in which fiberglass insulation already exists. Grab a tape measure and a flashlight to see what kind of insulation you already have in the attic and how deep it is. 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.

Subtract the cavity depth from the thickness of the batt in inches. Learn more about where to insulate. Batt and roll insulation and loose fill sometimes known as blown in insulation. Loose fill insulation must be applied using an insulation blowing machine in either open blow applications such as attic spaces or closed cavity applications such as those found inside existing walls or covered attic floors.

Let s look at an r 19 batt in a 2x6 cavity step 1. For every x the insulation material is compressed the r value decreases by approximately one half of that percentage or x compressed.