Based on your r-value, which is determined on which climate zone your in., R-value is determined by the thickness or depth of the insulation.Most common attic insulation R-value in the US in R-38 for southern climates and R-49 for the Northern climates.
Measure the attic L X W, to get the square footage, each product covers differently.
If using Batts or rolled insulation, check you ceiling rafters spaces, common spaces are 15"-16" or 23"-24".
If using loose filled, optional measuring rulers can be purchased to help guide the depth required.
Google The U.S. Department of Energy (DOE) and the International Energy Conservation Code (IECC). There are guides to help you determine your Zone, along with recommended insulation properties.
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If you see you rafters, You need to add more.
Best to ask a professional.
You can always rent a machine from Home depot. The bags are marked.
Measure you space Length x Width GET CURRENT DEPTH
Or you could get quotes for Spray Foam to keep your whole attic conditioned.
Measure the attic space for square footage and find out how many square feet of insulation you need.
The California Code for Insulation requires thickness of R30 rating and higher (we use R38.)
If the home is 10 years old or older just need to know the square footage and if it’s one story or two story and based on that we can calculate a number to upgrade the attic to a combined 14 1/2 inches known as R-38 which is the UBC / uniform building code for new construction.
We place markers in the attic and leave them there permanently to show the homeowner that they are receiving the proper amount of insulation. We only use the best on the market by Certainteed and will never settle and is a green guard product approved for hospitals and school applications.
To be to code, it has to be at least 16 inches. If you take something to measure up there, you can tell where you’re at with insulation. We can do an attic cap, which is just adding insulation on top of the current insulation.
Really depends on if there is inspections or not. At minimum r-30 is required. Some towns will require r-49 which is the new codes for roof insulation.
To give you a basic answer is not the easiest thing to do for knowing how much insulation you need in a given area. It depends a lot on what you’re looking for fiberglass cellulose spray foam. The basic is you could take your area length times the width and you can get the amount of square footage that you have for your attic space, then bending on what type of material you want to put in will give you an idea of the cost.
But everything is built differently and how things are applied are different but the best thing to do is when somebody is really interested is to have a professional come out and measure it and get a price that way. In some areas they rely on a prescriptive amount of insulation that needs to go into attic space walls basements so on and so forth again depending on what you’re looking for.
I install spray foam insulation so the best thing to do sometimes is to Google spray foam insulation and you can get a national average and there’s usually calculators to tell you how to measure. That’s usually the best thing to do and you can figure that out for fiberglass or blown-in cellulose. Just remember out of the three things I mentioned fiberglass, cellulose, and spray foam insulation. You will find that the spray foam insulation is the only one that stops all the air movement and keeps moisture out and that’s what you’re really looking for more than anything else.
An R 38 is recommended. That is generally about 10 inches.
Measure the height and width of any windows or doors in the wall. Multiply the measurements to find the area of each window or door, and subtract them from the total square footage of the wall. This gives you the square footage of insulation you need for that wall
The way you know how much insulation you need on your attic space is by following the city codes on the residential title 24.
Normally every homeowner should have R30 R value in the attic space witch is equivalent to 10.5” thickness of either fiberglass blanket insulation or blown in insulation, with that said you can always upgrade the R value to a higher thermal performance, the thicker the insulation the better performance, you can go up to R-60 R value,
R30 = 10.5”
R38 = 12”
R49 = 16”
R60 =20”
And so on
For blow-in insulation we recommend to go up to 12-13 inch.
If you decide to go with batting insulation.
So the minimum for attic will be R-30.
In our climate zone building codes state that R-38 is the bare minimum, but energy star recommends R-49.
Get a pro to estimate it for you. In many cases they can install it for less than you can buy it for. The insulation type, vapor barriers, venting, and use of faced/ unfaced are all dictated by your climate to help prevent condensation and mold growth issues. A pro in your area would be able to advise you on best practices rather than gambling and creating a mold growth environment.
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The R-value is the thickness of the insulation.
Here is a great tip:
Divide the R-# by 3, and you will get the thickness in inches.
R-30 = 30/3=10"
R-38 = 38/3= 12.4"
For attic we recommend R-38.
to calculate the square attic footage for insulation, get your property square footage and add 10%.
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