Hollow core doors are an inexpensive alternative to solid core doors for interior applications. Manufactured by wrapping a frame reinforced with structural paper or foam blocks with wood laminates, the doors are easily damaged. Repairing a hollow core door is an easy do-it-yourself home improvement project that will take approximately one hour to complete.
Place the dust sheet under the door to protect flooring. The spray foam is very messy and hard to remove from some surfaces.
Fill the hole in the door with the spray foam. Apply a generous amount to the inside of the door's cavity to strengthen the area around the hole. Allow the foam to expand beyond the door's surface and dry overnight.
Shave the foam using the flat razor blade. Remove the foam to a level just below the door's surface. This provides a solid foundation to hold the plastic filler compound.
Fill the damaged area with a plastic body filler or putty. The filler mixes with a hardener that activates it. Fill the damaged area using a putty knife and allow it to dry.
Sand the damaged area with fine sandpaper. Prime the entire surface of the door with an applicable primer and allow it to dry. Paint the door with a suitable finish paint to complete the project.
Wear disposable plastic gloves when working with spray foam. It is difficult to remove from exposed hands.
Although this method will work for a stained or varnished door, the patch will remain visible after completion. Follow manufacturers' directions and warnings on spray foam can. Use paint and spray foam in well-ventilated areas.