6 Steps To Install Window Casing

Over the past couple of months, I’ve been slowly but surely been casing each of the windows in my home. I’ve always loved the timeless look that window casing provides! Casing your windows is an easy DIY project that can be accomplished and will instantly upgrade the appearance of your home. So without further ado, here is how to case a window!

Final window casing in dining room

Supplies & Tools

  • 1″x2″ boards cut to size
  • 1″x4″ boards cut to size
  • 1″x6″ boards cut to size
  • 1″x8″ boards cut to size (some home’s are able to use 1″x6″ boards for the window sill, ours our deeper)
  • Caulk
  • Wood Filler
  • Paint

Step 1 – Install the Window Sill

Measurements for window casing

First, remove the blinds from the window. Then cut the 1″x8″ board to the correct length. You want the 1″x8″ board to extend 4.5″ past the edge of the window. Once the board is cut to the correct length, use the irregular shape duplicator to measure the depth of the window sill and trace both of the corners onto the 1″x8″ board. Next, use a jigsaw to cut out the corner piece of the 1″x8″ window sill. Finally, install the 1″x8″ board with a finishing nailer.

The window sill board is the most important piece as the rest of your measurements depend upon the window sill being installed.

Step 2 – Install the Piece Under the Window Sill

Installing the piece under the window sill for window casing

Next, cut the 1″x4″ board that will go under the window sill to a length that is 2″ shorter than the 1″x8″ window sill. Install the board underneath the window sill using a finishing nailer so that it is 1″ shorter on each end.

Step 3 – Install the Side Pieces

Installing the side pieces for window casing

These 1″x4″ side pieces will rest on the 1″x8″ window sill and will run clear to the top of the window. Make sure that the 1″x4″ side pieces are long enough to extend past the clips to take out the blinds, otherwise, you won’t be able to get your blinds out! Once the 1″x4″ side pieces are cut to the correct length, install them using the finishing nailer.

Step 4 – Install the Top of the Casing

Installing the top pieces for window casing

Measure from the edge of one side 1″x4″ piece to the other 1″x4″ side piece. Cut a 1″x2″ piece to this length. Next, install the 1″x2″ piece laying flat on the side 1″x4″ pieces (not so it’s flush, there should be an overhang) using the finishing nailer.

Cut the 1″x6″ piece to the same length as the 1″x2″ piece and install using a finishing nailer.

Finally, cut the last 1″x2″ piece to the same length as the other two. Install the final 1″x2″ piece in the same orientation as the first using a finishing nailer.

Step 5 – Reinstall the Blind Cover

The blind cover will need to be cut since they usually overhang the window. Measure the inside width between one panel to the next, mark how long the blind cover should be, and then cut to the correct size using a miter saw. Make sure that the magnets are within the distance, you don’t want to cut them off. Reinstall the blinds, and then place the blind cover back into position.

Step 6 – Finishing Work

Next, fill in all of the nail holes using wood filler, wait for it to dry, and then sand to get a smooth finish. Then caulk all of the edges and seems to give it a completed look. Next, use a paintbrush to paint any areas of the window trim that can’t be reached using a paint roller. Finally, use a paint roller to finish painting the window casing.

Finished window casing in dining room

The Final Product!

And that is how you case a window! It’s a really easy project that doesn’t take a lot of time to complete but can completely transform how a room looks and feels. The nice thing about this project is you don’t have to do them all at once, you can do one here and another there and soon enough your whole home will be completely transformed!

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