Calculating the Amount of Paint Needed to a Paint a House

To estimate the number of gallons of paint needed to cover the outside of a house, first multiply the distance around the building by the average height (if the building has gables, add two feet to the average height before multiplying). Then check the label on a can of the paint you intend to use and find out how many square feet each gallon of the coating will cover. Finally, divide the calculated square footage by the second number and you should be close to an answer.

Close, but not right on, until you allow for the porosity of the surface being covered. A corrugated metal wall will need one-third more paint to cover it than a flat metal one and you'll find that paint goes 10% farther on wide-lap siding than it does on narrow.

Any surface that is noticeable dry, rough and/or porous will drink up at least 20% more coating than a similar surface that isn't, and you should always figure on using an extra 50% of your paint when applying the first coat to concrete blocks.

By Ron from Cortez, CO