How to Cut an Opening in Lap Siding

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  • 1-3 hours
  • Intermediate
  • 0-400
What You'll Need
Measuring tape
Chalk line
Circular saw
Wood cutting blade
Hammer and nail puller
Wood Chisel
Pencil or marker
A helper

If you would like to create an opening in the lap siding on your home—like to install a window or a door—you will need to know how to correctly cut out the opening in order to avoid damaging the areas of the lap siding that will not be removed. This two part series of articles will walk you through the entire process of cutting out an opening in the lap siding on your home. Let's get started.

Step 1 - Choose a Location for the Opening

Before you begin, you should carefully consider the location you'll be using for the opening in your lap siding. If you'll be installing a door or window, you might want to consider any other obstructions that may be on the inside of the house, such as a wall or structural beams of supports that can not be moved.

Step 2 - Measure and Mark Corner Borders

wood lap siding on a building

Once you have chosen a suitable location for the opening in the lap siding, you should measure the dimensions of the opening and create marks at the corners of the borders with a pencil or marker. You should create marks for the four corners of the opening, so you can use those as guides for creating cutting lines with a chalk line.

Step 3 - Create Chalk Lines for Cuts

Have someone help you to make chalk lines you will need to outline the opening in the lap siding. In order to create the chalk lines, you and your friend will both need to take one end of the chalk line and hold it tightly between two of the corner marks you created earlier.

Once the chalk line is taut, snap the chalk line to create the line between the two marks. Continue this for creating lines between the marks for the other corners. When you finish, you should see a rectangle or square shape drawn on your wall.

Step 4 - Score the Cut Lines

Hammer, chisel, saw, level, and pencil

After you have finished creating the chalk lines, you can use the hammer and wood chisel to score along the length of the chalk line to create a cutting guide for your circular saw. To do this, hold the chisel in one hand and align the chisel head with the chalk line. Then, strike the butt of the chisel with the hammer and continue doing this until you have scored along the entire length of the chalk line. When scoring the line, drive the chisel to a depth of about 1/8-inch. Repeat this process for the other three lines in your opening.

Step 5 - Cut the Lap Siding along Scored Lines

Using the line you scored with the hammer and chisel as your cutting guide, use the circular saw to cut along the length of the line. Set the depth of the blade to about ¼-inch, and cut the lap siding in small increments. Between each cut, adjust the blade depth so it is deeper by ¼-inch. Don't cut all the way to the edges of the lines or the corners. You will use a different type of saw to do this later.