How Much Insulation for 600 Square Feet?
Bags or rolls
6 bags
600 square feet of wall or ceiling, framed at 16 inches on center, with 106.8 square foot bags.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Wall or ceiling area600 sq ft
- Stud or joist spacing16 in
- Coverage per bag or roll106.8 sq ft
Bags or rolls6 bags
| Gross area | 600 sq ft |
|---|---|
| Framing factor at 16 in oc | 90% |
| Cavity area to insulate | 540 sq ft |
| Bags at 106.8 sq ft | 6 |
| Coverage bought | 641 sq ft |
The material list this produces
| Insulation batts, bags | 6 |
|---|---|
| Vapor retarder, sq ft (if required) | 600 |
Coverage per bag compared
Bag coverage is the number that decides this, and it is printed on the bag. Here is the same area at five common coverages.
| Coverage per bag | Bags or rolls | Coverage bought |
|---|---|---|
| 40 sq ft | 14 bags | 560 sq ft |
| 50 sq ft | 11 bags | 550 sq ft |
| 75 sq ft | 8 bags | 600 sq ft |
| 90 sq ft | 6 bags | 540 sq ft |
| 106.8 sq ft | 6 bags | 641 sq ft |
What else matters here
Six hundred square feet gross, 540 of cavity, six bags, 641 square feet bought.
How much R value that wall should have is a climate question and the code answers it by zone. Broadly, wood framed walls run around R-13 to R-15 in the warm south, R-20 or R-13 plus continuous exterior foam through the middle of the country, and R-20 or better plus foam in the cold north. The zone map and the table are in the energy code your jurisdiction adopted, which is often an older edition than the current one.
Insulating above code is usually cheap while the wall is open and expensive afterwards, so the question worth asking is not what is required but what the incremental bag costs against the next thirty years of heating. The answer is almost always to fill the cavity properly and spend the argument on air sealing instead.
What this calculator assumes
- Framing takes up roughly 10 percent of a wall at 16 inch on center and 7 percent at 24. Cavity area is reduced accordingly, so you do not buy insulation for the studs.
- Bag coverage varies a lot by R value and width. The default is a common R-13 kraft faced batt bag; read your own bag and change it.
Questions people ask
How many bags of insulation for 600 square feet?
Six bags at 106.8 square feet per bag, covering the 540 square feet of cavity left after framing.
What R value do exterior walls need?
It depends on the climate zone, roughly R-13 to R-15 in the south and R-20 or R-13 plus continuous exterior foam further north. The energy code your jurisdiction adopted has the table.
How much does one bag of batts cover?
It is printed on the bag and it moves with R value and width. The default here is a common R-13 kraft faced batt bag at 106.8 square feet. Change it to whatever you are actually buying before you trust the count.
The insulation calculator takes any dimensions you like and hands back the same list.