Estimating the amount of clapboard siding you need for your house requires simple measuring and basic mathematics. Enlist the help of another person in taking the measurements of your house.

### Things You'll Need

- Pencil
- Paper
- Tape measure

- Ladder
- Calculator

Draw a basic sketch of each side of your house. Break the drawings down into rectangles and triangles. For example, the first floor of the house may create a rectangle with the peaked roof a triangle sitting above the rectangle.

Choose one side of the house as a starting point. Use a tape measure to measure the height and length of any rectangles. Use a ladder to reach the higher edges of the house. Write down the measurements on the corresponding walls in your drawing.

On the same side, measure the base length and the height from the base to the point of any triangles, using a ladder as needed to reach high areas. Write down the measurements on the corresponding parts of your drawing.

Repeat the measuring steps for each of the remaining exterior walls of the house. Make sure to record the numbers on your drawings.

Measure the height and length of any windows and doors on the exterior of the house. Record the measurements on one of your drawings.

For each rectangle, multiply the height by the length to obtain the area of the space. For each triangle, multiply the height by the length, then divide the answer by two to obtain the area of the space. Add together all of the areas for the total exterior surface area of the house.

For each window and door, multiply the height by the length to obtain the area of the space. Add the areas of all the windows and doors together. Subtract this number from the total exterior surface area of the house. The resulting number is the amount of square footage of clapboard siding you require.