The floor insulation can simply be left in place if you re now heating the attic.
Compressed insulation attic.
What is attic insulation.
Then use the numbers in the chart at right to estimate its 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.
R value simply means resistance to heat flow.
Subtract the cavity depth from the thickness of the batt in inches.
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.
When compressed to less than its labeled thickness glass fi ber insulation will experience a reduction in r value.
See install batt and roll insulation for details.
There are two main types of insulation.
Insulation loses its effectiveness when it is constantly being compressed by being walked on or having boxes stored on it loses its insulation ability.
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.
Batt and roll insulation works well between joist and stud spaces or if you have a wide open space or a crawlspace.
To make a niche i want to compress the insulation quite a bit down to only 1 5 or 1 75 inches.
Over the years fiberglass batt insulation gradually collapses and deteriorates.
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.
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 and loose fill sometimes known as blown in insulation.
Loose fill blown in insulation is best for tight spaces or if your attic already has a layer of insulation.
Most manufacturers use 40 to 60 recycled glass content.
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.
Yes the compressed r value can be estimated using the following method.
Learn more about where to insulate.
For every x the insulation material is compressed the r value decreases by approximately one half of that percentage or x compressed.
This lowers the insulation s r value.
