How to Anchor a Basement Window

Cut and clear out the window opening in your concrete basement wall. Remove any loose material or debris along the edges of the opening so there is a clean and flat surface on which to mount your window frame.

Cut the 2-by-10 inch timbers to the same thickness as your basement wall with a circular saw. They should fit flush against both edges of the wall when laid in place along the window opening. Use your tape measure to record the length of all four sides of the window opening.

Cut four lengths from the 2-by-10s to fit the opening measurements. Use your hammer and nails to assemble your four 2-by-10s into a square-shaped sleeve with the same dimensions as your window opening. The sleeve can then be anchored to the basement wall, where it serves as a mounting place for your window frame and window. Cut precisely so the fit is tight, and use your hammer to force the sleeve into position.

Use your hammer or small sledge, and concrete nails to anchor the top and bottom plates in place first. Drive each nail into the mortar joints between the concrete blocks that make up your wall. Perform the same steps for the side plates.

Lift and place the new window and frame into the wooden sleeve you have just installed. The frame can then be leveled with shims and fastened to the sleeve with wood screws.