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Types of Roofing - Configuration Calulations

Roof Calculation - Roofing Squares on your house:


A roofing square is equal to 100 square feet.

Reinke Shake LT's 
The World's Finest Metal Shingles !

Roof Quantity Calculation for Reinke Shakes


For conventional homes:


1.  Looking down on your house, separate it into rectangular sections.

2.  Determine the length and width of each section ( include the distance the roof overhangs the outer wall ).

3.  Multiply the length and width of all the rectangles.

4.  Add the multiplied areas together.     This would be the roof area if you had a flat roof.

5.  Multiply the area by the slope factor ( chart below ).

6.  Divide the final number by 100 ( example, 2050 would take 20.5 squares ).

7.  Another way is to take the extreme length and extreme width of your house ( with the overhang ) and subtract all the areas where the house notches in.


Slope Factors:    Slope is how much higher the roof is at 12" closer to the peak.


2 in 12   1.014                                 5 in 12   1.083                              8 in 12    1.202

3 in 12   1.031                                 6 in 12   1.118                            10 in 12   1.302

4 in 12   1.054                                 7 in 12   1.157                            12 in 12   1.414


Ridge and Hips take 1 square of Reinke Shakes LT shingles for every 96 feet of length.


Geodesic Domes:


A close estimate is 'Diameter' X 'Diameter' X .015 equals the number of squares. 

For extensions on the dome, use the conventional home formula above and add it to the dome number.

( example,  45 foot dome:  45 x 45 x .015 = 30.375  Therefore approx. 30 1/2 squares ).




A very frugal roofer will have less than 2% waste.  Other roofers will have over 10%.   The best roofers will closely weigh the cost of labor, verses the cost of wasted materials.  They will add on up to 8% for waste on cheap shingles, but for more expensive shingles it will be closer to 3%.

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