How to Reseal an Exterior Door

Take off the doorknob and deadbolt lock by unscrewing the mounting screws on the interior side of the door, using the Phillips screwdriver. Remove the lock and knob from the door.

Apply a strip of painter's tape around the exterior door's window pane, if applicable.

Sand the exterior door's old sealant with a medium-grit sanding block until the door has a smooth surface. Sand off the old sealant's flakes and chips. Use the sanding block's corners to clean old sealant from the grooves and designs in the door and trim.

Clean the exterior door with a clean, dry rag or tack cloth. Completely remove all dust from the door's surface.

Lay a dropcloth on the floor below the door.

Stir a can of exterior door sealant with a paint stick, using the sealant manufacturer's recommended mixing directions. The time required to thoroughly mix the sealant depends on the type and color of the sealant.

Apply a thin coat of sealant to the exterior door's edges, using a foam applicator to spread the sealant evenly.

Cover the surface with a thin coat of sealant, using the foam applicator to follow the grain of the wood. Coat the door's trim designs with the applicator's corner, using a dabbing motion to fill the recesses. Let the sealant dry completely.

Sand any bubbles and runs from the sealant's base coat with an extra fine-grit sanding block, working with the wood grain. Clean dust from the exterior door with the rag or tack cloth.

Apply a second coat of sealant to the exterior door, using the same method as the first coat. Repeat until the door has the desired finish, as each additional coat will darken the finish.

Let the sealant dry completely before removing the painter's tape and reinstalling the doorknob and lock.