How to Attach a Window Seal to Cement

Build the cement wall by a window seal so that it comes within ¼ inch of the window frame if you don’t already have the cement in place. Allow the cement to fully dry before attempting to attach the cement to the window seal.

Apply masonry primer to the edge of the cement wall surface with a thin paintbrush. Use a thin, even layer and allow the primer to dry for the length of time recommended by the manufacturer.

Brush an even layer of an appropriate primer, such as masonry primer, on a cement or concrete window or wood primer on a wood window, onto the side of the window frame closest to the window seal. Allow the primer to dry fully before attaching the wall and window surfaces.

Cut the tip of a masonry caulk or butyl rubber tube down so that it fits inside the crack between the cement surface and window seal. Insert the tip into the top of a gap between the wall surface and frame, and squeeze the tube to fill the space between the cement wall and the window with caulking. Continue inserting caulk or rubber into the space until the entire crack is filled to the surface.

Leave the caulk or rubber to settle in the crack for 2 to 3 hours to allow it to settle. Go over the crack again and fill the crack back to the surface. Repeat the process for the other gaps around the window to attach the cement to the entire perimeter of the window seal.