How to Install Mitered Window Casing Part 2 How to Install Mitered Window Casing Part 2

What You'll Need
1x4-inch Lumber
Miter Saw
Tape Measure
Drill/Drill Bits
Finish Nails
Wood Putty

Now that you have the first part of your window casing project completed, you can then move onto the second part. In the steps below, you will finish off by installing the horizontal pieces and adding wood putty to fill the nail holes.

Step 1: Measure for Top and Bottom Pieces

Measure for the top and bottom pieces of the window casing to ensure a tight fitting miter cut. Start to measure for the top piece, from the top of the side piece across to the top of the other side piece. This will give you the overall length.

Once you have that measurement, you will measure the bottom part of the side casing that is along the top edge of the window. Measure across to the other side edge. Mark these two measurements on your top casing board. Draw a line with the carpenter's square. You should have a 45 degree angle line. Repeat the process with the bottom piece.

Step 2: Cut Casing Boards to Length

Set up your miter saw to cut the 45 degree cut on the top and bottom casing boards. Set the top board onto the cutting platform and line up the blade. Chop the saw through the wood with a smooth action. Repeat the process until all the angle cuts are made.

Step 3: Install Top and Bottom Casing Boards

Now that the cuts have been made you should have boards that will fit perfectly into the place. If they are a little tight, then sand the edges a little until the fit nice and snug. Apply some construction adhesive to the back of the top board and press it into place. Repeat this process with the bottom casing board. 

Step 4: Pre-Drill Pilot Holes

Once you have the boards in place, you can then drill in some pilot holes like you did with the side pieces of the window casing. Space them about 6 to 10 inches apart. 

Step 5: Nail Boards to Wall

Use your hammer to nail in the remaining two casing boards.

Step 6: Fill in Nail Holes

Once all of the casing boards are installed and they are all straight and fit together snug, go around and fill in the nail holes with wood putty. Use a small, flat scraper to spread a small dab of putty to each of the holes. Make sure that the entire hole is full. If there are any empty spaces in the mitered section, fill those in with wood putty also. Allow the putty to completely dry for the amount of time indicated on the packaging, and then sand them smooth with the rest of the wood.

Step 7: Stain or Paint

Your metered window casing is now complete. Finish this project by applying either paint or a stain to the wood. Make sure that the wood is clean of any dust, and apply a primer to the wood. Spread out the stain or paint with a foam brush to minimize any brush strokes. 

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