Most post-World War II homes have hollow-core doors. The "core" of the door usually consists of pieces of cardboard crisscrossed on end for rigidity and modest acoustic value. The door is then finished on both sides with a one-eighth-inch layer of veneer plywood or hard board.
Birch and mahogany are the most popular finish for "real wood" veneered hollow doors. These can then be stained and varnished or painted, if desired. The vast majority of hollow-core doors are constructed with a hard board veneer and come factory-primed and ready for paint.
Gaping holes in wood veneer doors are significantly more difficult to repair than those in the painted counterpart. Aside from replacing the door with a new one, the best bet is to apply an added layer of one-eight-inch veneer to cover the entire damaged side.
The sheet of veneer plywood, which can be purchase at most lumber yards or home improvement centers, should be slightly larger than the door. The material should overhang about an inch on all sides.
The face of the existing damaged door should be rough sanded with about an 80 to 100-grit paper. Remove all of the sanding dust with a vacuum or tack cloth before attempting to attach the new veneer.
Use a throwaway paint brush to apply a coat of contact cement on both the sanded face of the door and the back side of the veneer. Allow both surfaces to sit for several minutes until the contact cement becomes tacky.
Lay the sheet of veneer over the face of the door, merging both layers of contact cement. Lay the glued side of the door face down on a flat surface like a concrete garage or patio floor and place a few evenly distributed heavy objects on the door for a lasting glue job.
Allow the door to dry overnight and trim the edges with a router. Complete the job by finishing the door with stain and varnish or the desired finish.
Repairing holes in painted hollow-core doors is a breeze compared to those with a wood veneer.
In contrast with the repairing of wood veneer doors, painted doors can be patched, puttied and painted, making the damaged area virtually unnoticeable.
Start by cutting out the damaged area. Make a pencil mark in the shape of a square surrounding the damaged area. Use a razor knife and rat-tail saw and cut along the pencil line to remove the damaged piece and make room for the new patch material.
After removing the patch material, cut a piece of backer board from a scrap piece of quarter-inch plywood. Any kind will do. The backer board should be about two inches larger than the patch area so that it can be attached to the inside face of the damaged veneer.
Drill a small hole in the center of the backer board. This will serve as a finger hole so that you can hold it in place while securing it with glue and screws.
You'll have to cut the backer board in half in order to get it through the patch opening.
Apply a bead of white glue to the perimeter of the backer board and cinch it up against the inside face of the veneer using a handful of half-inch drywall screws. The finger hole will help in positioning and holding the backer board in place during this process. Allow the glue to set overnight and remove the screws.
With the backer board firmly in place, the actual patch material can be installed. The patch itself is made by fitting a piece of eighth-inch veneer plywood or hard board into the hole and gluing it to the backer board. Use two pieces of silver duct tape crisscrossed over the patch to hold it tightly in place against the backer board. It's best to allow the glue to set for several hours before removing the duct tape.
When the glue has dried and the duct tape has been removed, fill joints and cracks with a wood filler such as a vinyl spackling compound. Because the compound tends to shrink, more than one coat may be required. Sand the spackling compound and a small area surrounding the patch with 120-grit paper.
Finish the project by priming the patch and applying a finish coat of paint. For best results, lightly sand, prime and paint the entire surface of the door.
