Buying wallpaper is undoubtedly exciting. The work that goes into deciding just how much paper you need however can be quite dispiriting. Yet you don’t need a degree in Math to work this out. With the correct measurement of the surface area you are working with and correct knowledge of wallpaper dimensions, you will be well on your way to properly planning for your purchase.
All you need is to follow these simple tricks.
Measure the Surface Area
You will need a measuring tape, a pen or pencil and somewhere to note your measurements.
Measure the length of the walls that you plan to wallpaper
Simply extend the measuring tape from one corner of the wall to the other. Note this measurement and round it up to the nearest whole number. Do this for all the walls, remembering to round up the measurement if it is not whole. If for instance, the length is 159.25 inches, round this up to 160 inches.
For a rectangular room, you could simply measure two of the walls and multiply each length by two. However, this may run the risk of not getting entirely accurate measurements because the walls may not be perfectly symmetrical.
Measure the height of the walls
Find the highest point of the wall and use it as your measurement point. Remember to round your number up to the nearest whole number.
Convert all your measurements into feet or metres
Wallpaper dimensions are usually given in square feet or metres . Convert the measurements you noted down into these figures so that it is easier to work out what you need. If your figures are in inches, divide your measurements by 12 to find the total distance in feet. If they are in centimetres, divide by 100 to find the distance in metres.
Calculate the surface area of the walls
Add the lengths of each wall to find the perimeter of the room. Find the total surface area by multiplying the total length by the height. To be more accurate, you could deduct the surface area covered by any doors or windows. On the other hand, it is considered more prudent not to deduct them as it is better to have more material rather than less.
Calculate any other relevant surface area
This could be any sloped wall that will need to be covered with wallpaper. If for instance, it is shaped like a triangle towards the top, you will need to measure this surface area separately. Find one corner at the bottom of the triangle and measure the length to the other corner. Measure the height from the bottom of the triangle to the tip of the triangle. Use the formula for finding the area of a triangle to find the surface area. (½ base*height)
Determine the Number of Rolls you will Need
Consider pattern repeats on the wallpaper
To achieve a smooth finish, you will need to match the patterns on the wallpaper all the way to the top of the wall. Look at the edge of the paper to find two identical parts of the pattern. Find on a point on the pattern and measure the length to where the pattern repeats itself. Assuming the wallpaper has floral patterns, measure the distance from the center of one flower to the center of the next similar flower.
If however, the pattern is random and non-repeating, there will be no need for this measurement. Often, the pattern repeat will be indicated on the packaging so be on the lookout for that.
Find the amount of usable wallpaper per roll based on the pattern measurement
Even though the surface area of the wallpaper will be indicated, the amount that will be actually usable will largely depend on the pattern and how much you will need to trim it to line it up. Divide the height of the wall by the length between the pattern repeats. If the figure is a fraction, remember to round it up to determine how many repeats you will require and thus how much wallpaper you need.
Find the number of rolls you will require in total
Finally, take the total surface area of the wall and divide it by the surface area of the usable wallpaper per roll. Once more, round this up to the next whole number.
Account for extra paper
When you have the total number of rolls you need, add about 10-20% of these to cater for any mistakes that may happen while fixing it, or for any future uses.
As a further measure to be certain that you get what you need, take your estimations with you as you head to the retailer for another pair of eyes.
A few tips for you to keep a note of:
❖ Make sure you order all your wallpaper from the same batch. Manufacturers use new colors and dyes each day. If you use different batches, you may end up with different shades of what you thought was the same paper.
❖ While pricing for wallpaper is given based on single rolls, often they come packaged as a set of two rolls. Verify this before making your purchase so you don’t end up with half or twice more than what you need.