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Proper Installation of Basement Window Well Replacement to the Cement Block

Emily Patterson

Basement window wells are barriers installed on the outside of the window and connected to the foundation wall. They prevent water from coming in around the basement window. If the foundation is constructed with cement block, the window well are firmly attached to the cement block wall to prevent water from entering the window well and subsequently, seeping in around the window.

Proper Sizing

Install window wells in front of windows that are below ground level.

A properly sized window well is required for effective control of water around the basement window. If the previous window well failed to prevent water from entering the well, it may have been improperly sized.

Remove the soil in front of the window until the soil is one foot below the window frame. Measure the distance from the bottom of the excavated soil to the ground level. Make sure the replacement window well is 6 inches above the level of the soil so the height of the replacement window well must be the depth required with an additional 6 inches added to the height.

The replacement window well must be 6 inches wider than the window. Measure the window and add 6 inches to the width to be sure you purchase a window well of the proper width for your replacement window well.

Proper Installation

Proper drainage from the bottom of the window well is necessary to prevent water from accumulating in the window well. Remove an additional six inches of soil from the area below the window and fill with 6 inches of gravel.

The replacement window well will have holes for attaching the window well to the foundation wall. Place the window well in position and use a pencil to mark the location of each hole in the window well against the concrete block foundation. Masonry screws will hold the replacement window well securely to a concrete block foundation wall. Use a masonry drill bit to drill pilot holes in the concrete block. The size of masonry bit required will be noted on the masonry screw package. Apply a bead of exterior grade caulk to the edge of the window well. Align the replacement window well with the drilled holes and use a drill with a screwdriver bit to install the masonry screws. The caulk will create a seal between the concrete block wall and the window well to prevent water from entering the window well between the concrete block and edge of the window well.

Grade the soil around the window well so it slopes away from the window well. If the soil slopes toward the window well, it will create a pool and slowly seep under the window well and fill the window well with water.