Installation Instructions

4
Most homes’ surface areas are made up of a series of rectangles or triangles.
When estimating vinyl siding, estimate each rectangular or triangular section separately and add the totals
together. Rather than trying to multiply feet and inches together, simply round to the next highest three-inch
increment and use the decimal equivalent.
For example: 10' 1" would become 10' 3" or 10.25'
10' 5" would become 10' 6" or 10.50'
10' 7" would become 10' 9" or 10.75'
10' 10" would become 11'
Multiplication then becomes simple: 10.25' x 10.75' = 110.19 sq. ft.
When all the individual sections are added together, the total is divided by 100 for the total number of squares.
This will be rounded up to the next whole square.
Example House
A house is 40' x 30' x 9' feet high at the eaves.
Front is 40' x 9' or . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 sq. ft.
Back is the same or. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 sq. ft.
Right end is 30' x 9' to the eave line or . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 sq. ft.
Left end is the same or . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 sq. ft.
Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1260 sq. ft.
Calculating Gable Area
Width of the house is 30' with a 12" or 1' overhang, front and rear. This totals a gable width of 32'. The roof
pitch of this house is 5 in 12, which means for every foot of run, the gable rises 5". The run is always half of
the total width, in this case 32', so the run is half of that, or 16'.
To convert the 5" to feet, divide it by 12. (5 divided by 12 = .42 ft.)
To figure the height of the gable, multiply the run of 16' by the rise per foot or .42'. 16' x .42' = 6.72'.
This is the gable’s height at the center.
Multiply the width by the height: 32' x 6.72' = 215 sq. ft.
Multiply this by .75 to allow for waste in cutting along the rake.
215 sq. ft. x .75 = 161.2 sq. ft. in one gable. You have two gables,
so multiply 161.2 x 2 which = 322.4 sq. ft. of total gable area.
Add this to the 1260 sq. ft. figured for the walls, above.
1260 sq. ft. + 322.4 sq. ft. = 1582.4 square feet of total siding.
1582.4 sq. ft. divided by 100 sq. ft (1 square) = 15.82 squares. Round this up to 16 squares.
You notice that we did not deduct for openings and always rounded up,
so there is no need to add back to the estimate for cutting waste.
16 squares will do this job.
general estimating tips