use Siding Measurement and Scaling: Figuring and Ordering Materials
How to Figure Siding Materials for your House
OK, so you have your siding picked out, maybe even the color. Or perhaps you have a couple of selections and want to compare costs. First, you´ll need to figure up how much siding you´ll need for your house. Siding is typically sold by the square. 100 square feet is 1 square. It can also be sold by the board, or by the lineal foot.How many square your house is
To figure how many square your house is, you need to break each surface down to either a rectangle or a triangle. If your house has a gable end, you will make the wall a rectangle up to the height that it meets the roof, then you will break the gable into two triangles. The illustration in Fig. 1 shows the different dimensions of a house that should be measured, and how it should be broken up.
Before you install, measure the Rectangles
The rectangles are the easiest to figure. You basically take the length and multiply it by the height of the wall. This will give you the total square feet of that wall. Don´t worry about subtracting for windows or doors. For most installations, that siding will be used up to account for wasted material anyhow. The only time you would want to account for items like this is for a garage front or a wall that has more window area then actual siding. Then you´ll have to divide up the several small sections of actual siding and figure them individually.For triangle shapes, just multiply .5 times the length times the height of the triangle. For a typical gable (both sides are the same) that is, say 24 feet wide and 4 feet high at the peak (a 4/12 pitch roof), the gable itself will account for ½ square, or 48 square feet ( .5 * 24 * 4 = 48) since you´ll round up. According to the laws of geometry, this formula will even work if the roof pitches are different on each side.
There´s nothing worse then getting almost done and needing ½ square.
I´ve found a safe method is to figure each wall´s amount individually and any gables. For example, if you figure one wall as 285 square feet, and another as 215 square feet, just make the first wall 3 square and the second 2 ½ square (round up to the next half square). Figure any gables by themselves and add their total square. This will help you account for waste that will occur. There are always pieces left over that are too small to put anywhere. Another method is to add up all the total square feet for the house, add 10%, and then round up to the next square. Either way, the key is, there will be waste, buy extra. I can´t tell you how many jobs I´ve installed (measured by a salesperson) where siding was special ordered and not measured correctly. There´s nothing worse then getting almost done and needing ½ square.There are some other things to consider which depend on the type of siding you have selected. For example, if you chose vinyl, you´ll also have to get the trim pieces. If you chose cedar, you´ll have to get enough 1 x material to construct corners, as well as window and door trim. I´ll deal with specifics for each type of siding in it´s respective article.