How to Do Finishing Work for a New Window

Clean the window trim, inside and out, of any residue left over from the manufacturing or installation process using a pH-neutral cleanser. Use a sponge for the cleaning, and then rinse with clean water. Wait for the trim to dry before proceeding.

Place masking paper over the window and masking tape over the walls adjacent to prevent any over-brushing of the finish material. Lay a drop cloth at the base of the wall to catch any dripping finish material as well.

Sand the trim lightly with a medium-grit sandpaper to texture the trim and remove any glossy factory finish from the window. Wipe with a tack cloth after sanding to ensure a residue-free surface.

Cover the trim with a layer of primer, using a paintbrush to apply a light layer. Use a brush that’s as close to the width of the trim as possible. Begin with the side edges of the trim where it meets the walls, then cover the bottom and finish with the top. Paint the edges inside the trim against the windowpane next, following the same painting order. Finish the priming by covering the face of the trim, connecting the two covered edges. Prime both the inside and outside of the window, and then wait overnight for the primer to dry.

Use an exterior latex paint for the outside of the window trim and an interior paint for the inside. Cover the window with the paint color of your choice following the same application process as the primer layer. Use two or more light layers of topcoat, applying each until you conceal the primer color. Wait two hours between each layer for drying time, and then allow the final layer to dry for 48 hours before taking off the masking paper and tape.