R value of insulation?

My name is Jeff, I’m going through the insulation class and seem to be having trouble understanding how to read and understand the the chart. Any help would be great. Thanks.

What chart?

First step is to learn here if the chart on insulation is hard for you to understand. www.buildingscience.com

Break it down into materials used.

  1. Rigid Insulation
  2. Spray Foam Insulation
  3. Sprayed In Place Insulation
  4. Batt Insulation
  5. Loose Fill Insulation

Attics = Fiberglass & Cellulose
Between 3 to 3.5 per inch.

The wall and foundations are usually limitations.

Read more…http://www.grassroots.ca/homeowner_help_articles/insulation-explained.php

Remember, in most cases it is an approximation.


Like Robert said it is fairly easy when you break it down. Throw out the chart and make your own list. Look at at from a per inch prespective.
Cellulose blown in: 3.5 per inch
Fiberglass batt: 3.2 per inch
Life will be easier then.
You can try this site to get you going:

Good points guys but we still don’t know what chart he is stuck on.

I am assuming this one it is a wonderfully useful chart.

All you would do is find the insulation that you are looking at and take the depth measurement. Say you have 18" of fiberglass insulation that is 2.5R for every inch. So the formula reads…

2.5 x 18 = 45

You would have a R value of 45.

Hope that helps.