Step 1 - Area
To begin, you need to find the height and length of one wall of your house. If you have the architect plans, this will be a simple job. If not, you’ll need a tape measure and pencil to note the measurements.
Multiply the length of the wall by its height. This will give you the area of the wall in square feet. Repeat this for each exterior wall of the house. Add the areas from every wall together to come up with the total square footage of fiber cement siding you’ll need.
Step 2 - How Many Panels?
fiber cement siding pales are usually 8 feet long by 8 inches wide. This give a panel an area of 5.33 square feet. In order to determine your fiber cement siding cost, you’ll need to determine how many panels you need to cover your house.
Divide the total square footage for the house walls by 5.33. The answer will be the number of panels you’ll need. Allow another 10% for errors and problems.
Step 3 - Cost
To determine how much the project will cost you, call around building supply centers to obtain quotes for the materials.
Selected from: https://www.doityourself.com/stry/how-to-clean-hardboard-siding