How can you calculate paint qty for window grills?

Answer 1

Calculate the total square feet of surface and divide into the square feet expected to get out of a gallon of paint.

Lineal ft of grill per sash x thickness of grill material being painted

e.g. 1 average size double hung 6 light window sash -

3' x 5' window = 2 sashes aprox 2.5' tall by 3' wide

6 light window is 3 over 2 lights

so width of the sash is 3' divided by 3 lights or aprox 1' of grill width per light.

the sash is 2.5' tall and is divided by 2 lights or aprox 1.25' of grill height per light

W + W + L + L = 1 + 1 + 1.25 + 1.25 = 4.5 Lin ft per light.

yes I know the part of one light that adjoins another will be doubled. This is tedious enough without making that accommodation...

LF of each light - 4.5'

Rail thickness 2" Thickness of grill - its an inch give or take but since the perimeter of the grills are the sash rails and so we just want to average stuff together, call the rail thickness 2"

1 foot divided by 12 inches is .0833 per LF x 2" thick is 1.666 of SF per LF of rail.

.1666 SF per foot of rail x 4.5 LF of rail per light = .75 SF of grill per light

.75 SF of grill per light x 6 lights = 4.5 SF of grill per sash.

If you get 300 to 350 sf out of a gallon of paint, this works out to 66 sashes out of a gallon, or 33 windows, assuming I did this calc correctly. That means just buy 1 gallon of paint for the window sashes and you'll likely have more than enough... I hope:)

Matt R

nyc-hs.com