When it comes to rebonding of wall-paper in the room, first of all there is question: how many rolls to buy that it was not necessary to join on the foreground strip at the last minute "from pieces" or to move furniture to close "bald" places.
1. Measure perimeter of the room of the room (cumulative length of all walls) and subtract from it width of window and door openings. For example, 3 by 4 meters with one door (80 centimeters) and standard butterfly window (140 centimeters) the perimeter will be equal in the rectangular room to 11.8 meters.
2. Measure wall height. To the turned-out digit it is necessary to add 10 centimeters ("allowance" for cutting of wall-paper from above and from below when gluing). If you are going to glue wall-paper with the large drawing and you should "adjust" precisely pattern – add on also rapport step, that is repeatability of elements of pattern in centimeters (this information is usually specified on roll). Thus we receive the maximum length of one strip of wall-paper. For example, with height of walls of 2 meters of 40 centimeters at rapport in 20 centimeters and 10 centimeters of "allowances" total length will be 2 meters 70 centimeters.
3. Calculate how many whole strips you will be able to cut from one roll of wallpaper. Standard length of roll is 10.05 meters. Thus, one roll is equal in our case to three strips of wall-paper (and in case with the monophonic wall-paper which is not demanding adjustment or wall-paper with very small drawing from it it would be possible "to find" four strips).
4. Calculate number of strips which will be required to you. For this purpose the perimeter of the room needs to be divided into width of roll and to round to integer (upwards). Standard wall-paper has width of 53 centimeters, but for calculations it is better "to round down" this digit to consider possible curvature of walls because of which wall-paper in places should be glued with an overlap. Thus on 11.8 meters of perimeter we will need 24 strips of wall-paper.
5. Now the number of strips necessary for pasting of walls, we will divide into number of strips in roll. Also we will add one more roll for pasting of fragments of walls over door and window openings. Thus, on the room 3х4 meters to us are required (24 to separate 9 standard rolls into three plus one). At repair in rooms of the big square and also rooms with large number of windows or doors it is better to add two rolls.