To estimate the amount of wallpaper needed to paper a room. Measure the height of the room. Add on an allowance for trimming. And calculate how many lengths can be cut from one roll; the usual length of a roll is 10 m 33ft.
Multiply the width of the paper. Usually 520 mm by the number of lengths that can be cut from one roll. Ignoring doors and windows, unless they are extremely large, measure the perimeter of the room, divide this figure by the first figure to calculate the number of rolls required. Remember that fractions must be made up to the next whole number.
If the room has different ceiling-heights, such as a stairwell. Measure those areas with the same height and add the totals together.
Preparing paper for pasting
As most modern wallpapers are rolled with the pattern on the outside, problems can arise when pasting the paper. This is because. When the paper is laid on a table for pasting, the ends roll back into the length, which can result in paste getting on to the surface of the pattern.
Deal with this by planning the job in advance, so that all the lengths of paper required are rough cut to size and left lying on the pasting table overnight, with the patterned side downwards. Hold the ends down by loosely looping a length of string round the pasting table legs and over the combined lengths of paper.
Next day. The paper will no longer curl, making it much simpler to paste individual lengths.