HOW MUCH DO YOU NEED?

WALLPAPER

Before choosing your wallpaper, keep in mind that wallpaper with little or no pattern to match at the seams and the ceiling will be the easiest to apply, thus resulting in the least amount of wasted wallpaper. If you choose a patterned wallpaper, a small repeating pattern will result in less waste than a large repeating pattern. And a pattern that is aligned horizontally (matching on each column of paper) will waste less than one that drops or alternates its pattern (matching on every other column).

TO DETERMINE THE AMOUNT OF WALL SPACE YOU'RE COVERING:

• Measure the length of each wall, add these figures together, and multiply by the height of the walls to get the area (square footage) of the room's walls.

• Calculate the square footage of each door, window, and other opening in the room. Add these figures together and subtract the total from the area of the room's walls.

• Take that figure and multiply by 1.15, to account for a waste rate of about 15 percent in your wallpaper project. You'll end up with a target amount to purchase when you shop.

• Wallpaper is sold in single, double, and triple rolls. Coverage can vary, so be sure to refer to the roll's label for the proper square footage. (The average coverage for a double roll, for example, is 56 square feet.) After choosing a paper, divide the coverage figure (from the label) into the total square footage of the walls of the room you're papering. Round the answer up to the nearest whole number. This is the number of rolls you need to buy.

• Save leftover wallpaper rolls, carefully wrapped to keep clean.

INTERIOR PAINT

Estimate your room size and paint needs before you go to the store. Running out of a custom color halfway through the job could mean disaster. For the sake of the following exercise, assume that you have a 10x15-foot room with an 8-foot ceiling. The room has two doors and two windows.

FOR WALLS

Measure the total distance (perimeter) around the room:

(10 ft. + 15 ft.) x 2 = 50 ft.

Multiply the perimeter by the ceiling height to get the total wall area:

50 ft. x 8 ft. = 400 sq. ft.

Doors are usually 21 square feet (there are two in this exercise):

21 sq. ft. x 2 = 42 sq. ft.

Windows average 15 square feet (there are two in this exercise):

15 sq. ft. x 2 = 30 sq. ft.

Take the total wall area and subtract the area for the doors and windows to get the wall surface to be painted:

400 sq. ft. (wall area)

– 42 sq. ft. (doors)

– 30 sq. ft. (windows)

= 328 sq. ft.

As a rule of thumb, one gallon of quality paint will usually cover 400 square feet. One quart will cover 100 square feet. Because you need to cover 328 square feet in this example, one gallon will be adequate to give one coat of paint to the walls. (Coverage will be affected by the porosity and texture of the surface. In addition, bright colors may require a minimum of two coats.)