How to Calculate Area For Siding

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If you are planning to install new siding on your home, you must know the linear perimeter footage of your home in order to calculate how much siding you will need. This is a relatively easy task and involves some basic geometry calculations.

Step 1 - Draw a Diagram

First, draw a diagram of your house. Break the building structure down into basic geometrical shapes—rectangle, triangle, square, etc. Make a diagram for each side of your house and for any outbuildings onto which you will install the siding.

Step 2 - Measure the Building

Now, you will need to measure the length and width of each side of your house. Include each geometrical shape that your diagram includes.

Step 3 - Calculate for Linear Perimeter

    Measure each wall all around house. Measure wall height. Multiply both numbers together for area.

    Measure all gables height and width. Multiply width times height and then divide by 2 for area. Add area numbers together for total square footage, then add 10% for waste. Add all the area results together to obtain amount of siding to order.

    Siding Waste

    With almost any kind of siding installation, there will be waste caused by matching seams, cutting for doors or windows or simple unfamiliarity with the type of siding. To accommodate the waste, once you have your calculations for the building area, add a minimum of 10%.

    When you order or purchase siding, make sure you understand the supplier’s policy about returning any materials that you do not use. While it is often helpful to keep a small amount of extra siding available for repairs or damage in the future, if you have a great deal of excess leftover from installation, you may be able to return it for a refund.

    Ordering Siding

    Remember that you will not only need to order the siding that will go on your building, you must also order fascia, house wrap and any supporting materials that your specific type of siding requires for installation.

    Even if you plan to work with an installer, it is a good idea to do your own calculations to know how much siding you will need. Having this knowledge will help you evaluate the installer’s knowledge and understanding of your project.