Quick and Easy Guide: Installing Round Window Casing for Home Improvement

Before you begin, you’ll need to take some measurements to ensure the casing will fit and that you’ll have the right size for the round casing. As with any type of window casing, you will need to build the support for holding the window in place. Cut 2×4’s to the measurements you’ve taken of the window casing. Your support should include a top header and a bottom sill. Nail them into place with 8d nails.

To create the shape of the round casing, you’ll need to add corner supports to make a semi-circle. Typically, straight wood won’t work so you’ll need to close in the rectangular area around the casing. Measure from the corner to the casing, in each corner nail in a 2×4 piece. This should be secured with the edges at the measurement you took and with angles cut into each end.

Before setting the window in place, you’ll want to make sure it’s weatherproof. Lay a bead of silicone caulking on both the inside and the outside of the area where the window will go. When you’ve done the caulking, hold up the window casing into the hole you’ve prepared. It’s important to center it before securing it in place. Next use shims to make sure the window is level and then nail it in place with 8d nails. Be sure to use enough so that the window is held solid and doesn’t move.

Finally you’ll want to make sure that there are no gaps between the casing and the support lumber. Give the whole window one last bead of caulking for added weatherproofing and then cut off the ends of the shims until they’re even with the casing. Your round window casing is now ready to make an attractive addition to update and brighten your home.