So, you’ve decided that you’re going to take the plunge, you’re going to wallpaper a room or section of your house. Once you know which walls you would like to cover in wallpaper, the next question is how is wallpaper sold and then how much wallpaper do I need? For an in-depth explanation on this please see our blog on “How is wallpaper sold” to learn about rolls of wallpaper and their sizes and how get the correct measurements. But briefly, wallpaper is sold in rolls and these rolls differ in size but Sasi Wallpaper usually deal with Standard Rolls or USA Rolls. A standard roll is 52cm wide and 10m in length. A USA roll is 68.6cm wide and 8.23m in length.
Now, back to the wall you are wanting to wallpaper! First you need to take the measurements of the height of the wall (standard heights in South Africa are between 2.6m and 2.9m). Then take the running length or width of the wall. If the wall has windows and doors measure as if they don’t exist. It is important to be as accurate as possible, buy a 5m or 8m measuring tape from your local hardware store for this purpose if you can, they are always handy to have anyway.
Wallpaper rolls have an insert and this gives you all the information about your wallpaper. It explains how to hang the paper using a paste-the-wall or paste-the-paper method, it indicates the batch number and it also indicates whether the wallpaper has a pattern repeat.
Wallpaper designs usually have a pattern repeat unless they are textured or random matches. Some designs have a smaller pattern repeat such as 26cm and others a big pattern repeat like 64cm and some designs are half drop. This makes things sound very complicated.
Pattern Repeat is indicated by a distance in centimeters or inches, for example 26cm or 68cm. Wallpaper is printed using a cylinder or screen, the pattern repeat is dependent on the circumference of the cylinder and how many times the same design is printed onto the paper. This pattern repeat is added on the wall height when calculating how many rolls of paper you will require.
Pattern Match is indicated with arrows or written as straight, half drop or random. This pattern match allows for the wallpaper to be hung seamlessly, matching the pattern across the various drops of wallpaper. A straight match means that both drops will share the same horizontal plane to join up the two parts of the design. If the pattern is somewhere in between then it is an offset match. Random match means that there is no pattern to match, this usually occurs with textured wallpaper, and grass and striped patterns.
Calculating How Much Wallpaper you will need:
Once you have determined the width of the wall, divide it by the width of the roll. This will give you the number of drops required, but make sure to always round up.
For example, a wall of 3.2m wide. If you are using a standard roll of wallpaper with a width of 52cm, you would take 3.2m (3meters 20cm) and divide it by 52cm = 6.15 drops, round it up to 7 drops.
To calculate the drop length: take the wall height + pattern repeat (eg) 26cm + 15cm for trimming at the top and bottom.
For Example: wall height 2.6m +26cm+15cm = 3.01m.
Each roll has 10.05m of wallpaper on it. For this example, you will be able to get 3 drops from a roll (3.01 + 3.01+3.01 = 9.03). This means you would be left with 1.02cm of unused wallpaper. This is unfortunately waste as you cannot join wallpaper in the middle of a drop. If you need 7 drops and you get three drops from a roll you will need 3 rolls.
Here are the formal calculations for the above examples:
Wall width 3.2m
Wall height 2.6m
Pattern Repeat 26cm
Standard Roll 52cm x 10m USA Roll 68.6cm x 8.23
3.2 / 0.52 = 6.15 drops 3.2 / 0.686 = 4.66
6.15 rounded up to 7 drops 4.66 rounded up to 5
7 x (2.6 +15cm + 26cm) 5 x (2.6 +15cm +26cm)
= 7 x 3.01 = 5 x 3.01
= 21.07 ÷ 10m (roll) = 15.05 ÷ 8.23m roll
= 2.107 = 1.82
= 3 rolls = 2 rolls
There are many wallpaper calculators available online but they are not always accurate and it is for this reason that we recommend that our clients take a bit of time and do the calculations personally. However, if you are struggling to figure out how many rolls you will need or if the job is very technical, we do suggest that you ask an installer to come out and measure or alternatively you are welcome to stop by our showroom and we can assist you with the calculations.
For more information or to purchase wallpaper online please look at our website www.sasiwallpaper.co.za or contact us on +27 (0) 11 262 494