Help Calculating How Much Radiant Barrier You Will Need

Once you have decided on the best installation method for your project, you will be able to calculate how much Radiant Barrier is needed.

If installing over an attic floor...

If you are installing the radiant barrier over an attic floor you will need to calculate the square footage of the floor.

1. If you have a single story home with attic space over the entire house, the main floor square footage should be the same as the attic.  You can also refer to your homes appraisal for square footage.

2. If your home is multiple stories you will need to calculate the sqaure footage only of the areas that have attic space above.

Example: For this example we will use an attic foot print of 40' x 30'.

Step 1: 40' x 30' = 1200 s.f. (attic area)

Step 2: 1,200 s.f. / 1,000 s.f. (roll) = 1.2 rolls of Ecofoil Radiant Barrier.

In this example, we would need to purchase 1 roll of 4' x 250' and 1 roll of 4' x 125' Ecofoil Radiant Barrier for a total of 1,500 s.f.

 

If installing to the underside of rafters...

If you are installing radiant barrier insulation to the underside of the roof rafters, you will need to calculate the square footage of the roof area. At the bottom of this page is a roof pitch chart to help you calculate your roof area.

1. First calculate the area square footage of the foot print of the attic.

2. After you have the square footage of the attic, take that number x the factor that corresponds with your roof pitch. (See chart below)

3. If the roof is a standard gable roof, remember to measure the area of the gables (attic walls).  It is a good idea to cover gables with radiant barrier as well.

4. Finally, take your roof area number, add it to the gable number and divide it by 1,000 s.f.  This will tell you how many rolls of radiant barrier are needed.

 

Example:  For this example we will use the same attic foot print of 40' x 30' and our roof pitch is 6:12.

Step 1: 40' x 30' = 1,200 s.f. (attic area)

Step 2: 1,200 s.f. x 1.12 (pitch factor) = 1,344 s.f.

Step 3: 15' x 7.5' = 112.5 s.f. per gable. Two gables x 112.5 s.f. = 225 s.f.

Step 3: 1,344 s.f. + 225 s.f. / 1,000 s.f. (roll) = 2 rolls of Ecofoil Radiant Barrier

In this example, we would need to purchase 2 rolls of 4' x 250'  Ecofoil Radiant Barrier for a total of 2,000 s.f.

 

ROOF PITCH FACTOR CHART 

Pitch Factor
1:12 1.01
2:12 1.02
3:12 1.03
4:12 1.05
5:12 1.08
6:12 1.12
7:12 1.16
8:12 1.20
9:12 1.25
10:12 1.30
11:12 1.36
12:12 1.41