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Siding | Deck | Area Calculator

Wall Area Calculator

Here's a picture of a rectangle (green) plus a triangle (yellow.) Your home walls and deck will be comprised of shapes similar to these. With no intention to confuse these terms, we've simply called dimensions "height", "width", and "length" to keep them identified and to avoid using overly technical terms. Record the sizes (dimensions) of these areas.

InspectUSA Calculators Every time a wall changes direction, there is a new wall section as shown at left. Some will have triangular gable areas (yellow), and some will be plain rectangles (green).

Decks may have triangles and rectangles, as well as possibly circles.

Find all of these areas on the structure, and write down the dimensions in feet, as well as the type of area for each. Convert feet + inches to decimal feet (conversion table below). A  worksheet is availble to download and print.
The calculators below will compute areas and the amount of flat surface you need to cover.

Area is calculated by multiplying feet in width by feet in length (ft x ft) to get square feet (ft2.) The calculators below will do the math for you, including the formulas for areas of triangles and circles. For each surface area you measured, enter the appropriate values in the calculator(s), then write the result on your worksheet. When all areas have been calculated, add them all up to get the total square feet to be finished.

The conversion table (below left) show conversion from inches to decimal feet. For instance, if you measure 6 feet and 2 inches (same as 6'-2"), the value in feet is 6 + .17, or 6.17 (same as 6.17')

After entering a value, click outside the entry box to initiate the calculation

conversions

inches

feet

1

.08

2

.17

3

.25

4

.33

5

.42

6

.50

7

.58

8

.67

9

.75

10

.83

11

.92

In the calculator below, the "Triangle + Rectangle", calculates the entire area of a gabled house end, e.g., the sum of the tan and green areas. Enter all dimensions in feet.

Rectangle: Enter Width & Length
Triangle: Enter Length & Height
Triangle + Rectangle: Enter all three

WIDTH
LENGTH
HEIGHT
CALCULATED AREA =
ft2

ENTER DIAMETER

AREA
 1/4 = ft2
 1/2 = ft2
 3/4 = ft2
full =    ft2

Circles on your structure may be only half or quarter-circles, but all will have a diameter. Enter the diameter of a circle in feet at right to find the areas for 1/4, 1/2, 3/4 and full sections.


Checkpoints:
As you tally your results, make a "good sense" comparison as follows:

  • A 20' x 30' deck is 600 square feet
  • The area of the siding on a house will be roughly equal to its floor space (±10%). For instance, a one story, 30' x 60' house (about 1800 square feet) will have about 1600 to 2000 square feet of exterior siding
  • If your numbers seem vastly out of line, then re-check your written measurements! Also see the Roof Area Calculator


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