circumference = around
: Height x circumference
: then you take and divide circumference by 3.14
: the you divide that answer by 2
: then you X the answer by 2
: and then X that by 3.14 and you have your answer
: for the top portion of the cylinder
COVERAGE FOR DIFFERENT SHAPES
CHAIN LINK FENCES
Figure the square foot area as a solid and double it to allow for both sides. For spray, this will be fairly accurate since overspray must be considered. For roller, the coverage indicated in the product data sheets should be increased.
WALLS -- When figuring the square foot area, openings of less than 100 square feet should not be deducted.
OPEN WEB STEEL JOISTS
Original equipment manufacturers and fabricators generally dip these joists, as a first or shop coat. On all repaint work, by spray, these manufacturers recommend the paint be estimated by thinking of the joist as a solid rather than open web. Double for both sides.
To compute the square foot area of a stack multiply height (B) by the average diameter (A) and multiply that total by 3.
EXAMPLE: Diameter of stack at the top 5 feet.
Diameter of stack at the bottom 15 feet.
( 2 /( 5 + 15)
Average diameter = 10 feet.
Height 60 feet.
60 x 10 = 600.
600 x 3 = 1800 square feet of surface area.
DOWNSPOUTS & GUTTERS Measure the circumference in inches. To figure square feet, divide the circumference by 12 and multiply by total length in feet. Double this figure if the inside is to be painted.
PICKET FENCE Multiply the height by the length and multiply the result by four.
ESTIMATING PAINT REQUIREMENTS
OVER VARIOUS SURFACES
MOST EXTERIOR PRODUCTS WILL AVERAGE 400 TO 450 SQUARE FEET PER GALLON ON SMOOTH SURFACES; HOWEVER, SOME SURFACES, DUE TO IRREGULARITY OR ROUGHNESS OF THE SURFACE, WILL TAKE CONSIDERABLY MORE PAINT.
The following is an approximate estimate over various irregular surfaces.
It is advisable when estimating the square footage in the average residence to include areas such as windows, doors, etc. in the final figure. Deduct these areas only when they comprise a more than average percentage of the total area.