At the least the installer should know the pattern repeat, type of match, width of paper, and length of bolt. Probably the most difficult part of estimating is evaluating the amount of paper in a roll. There is no standard roll. Adding to the confusion, the imported machine print size of 20.5 inches by 33 feet is most often referred to as a roll in Europe and as a double-roll bolt here. For correct estimating, each project must refer back to the showroom, retail outlet, or producer to verify the packaging of the material.
Good communication is essential.
Once the method of packaging is clear, an accurate estimate can be made. Increasingly, the bolt size of 27 inches wide by 27 feet long is encountered. This size is not a true metric size, but rather a hybrid. Comparing the square footage of the room to the square footage of the roll is only marginally useful. Square footage itself is not a reliable indicator of the number of rolls required, especially for large-repeat domestic handprints.