How to Fix a Hole in a Door? (Step-By-Step Tutorial)

Introduction: How to Fix a Hole in a Hollow Core Door

By csledbetter

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When a hollow core door gets damaged, repair (rather than replacement) is possible if you can overcome the two issues that make such a repair difficult. First, these doors are hollow. There is nothing behind the MDF or hardboard surface skin of the door for a patch to adhere to, or to provide support to prevent subsequent cracking of the patch. Second, many hollow core doors have a texture molded into the MDF or hardboard to resemble wood grain. A smooth patch on such a door will stand out simply because the texture does not match.

Damage to these doors can be repaired by the creative use of products that were originally intended for something else. This Instructable describes how to use Insulating Foam Sealant to fill the void behind the damaged area and Silicone Rubber mold material and casting resin to reproduce the wood grain texture over the patch.

The main activities required to repair a hole in a hollow core door are:

  1. Fill the hollow space behind the damaged area with insulating foam sealant to allow filler material to be applied over the hole and to provide strength and support for the completed patch so it does not crack under use
  2. Use epoxy filler material to fill the damaged area and bring it flush with the finished surface
  3. Create a silicone mold of the finished surface texture of the door (in this case, a faux wood grain texture)
  4. Use the silicone texture mold and casting resin to reproduce the texture over the filled and sanded patch
  5. Prime the patches and paint the door

Step-by-step instructions to complete these activities are provided below.


2. Create a barrier around the perimeter of the hole

Take some paper towels and gently insert them into the hollow part of the door around the perimeter of the hole, or try this strategy from Jeff Shipwash, owner of Shipwash Properties (opens in new tab), who says: ‘I like to use a folded piece of cardboard or a thick poster board material.’

This will keep the foam which you’ll use next in the place where it’s needed.

How to fix a hole in a hollow door

To fix a hole in a hollow door you will need:

  • Utility knife
  • Paper towels
  • Low expansion foam
  • Spackle
  • Putty knife
  • 120 grit sandpaper
  • Paintbrush
  • Paint

Whats the fastest way to fix a hole in a door?

Using expanding foam and something to act as a backing board is a quick and reliable repair method. View our How-To here.

How to Fix Holes and Cracks in Wooden Doors

Another common problem with doors that homeowners encounter is cracks in solid wooden doors, occurring most commonly in exterior panel doors.

These unsightly cracks are caused by the inability of the wood panels to naturally expand and contract with changing temperatures and humidity levels. Layers of lacquer and paint hold the panels in place, and this rigidity ends up cracking the wood at weak points. If left unchecked, these hairline cracks can expand until, eventually, the door’s insulating properties are compromised.

Addressing these hairline cracks is not as difficult as many people think: this particular method was borrowed from boat builders and will leave you with a waterproof solution to cracked panels in your exterior door.

It is worth noting that, while this technique will extend the life of your door since the paint is still holding the panels in place, these cracks may continue to grow, and eventually, your door may need to be replaced altogether.


  • Utility Knife. A standard, an adjustable utility knife is an essential tool in this job.
  • Hacksaw Blade. A hacksaw blade or any semi-flexible metal blade will work in this application.
  • Flat Head Screwdriver. The width of the head isn’t of importance, as you will be using the screwdriver as a packing tool.
  • Putty Knife. Any size putty knife will work here.
  • Paper Towels. These are simply for cleaning purposes.
  • Paint Brush. A flat brush is best as you will be painting a flat surface.
  • Sandpaper. Fine grit sandpaper will help smooth your surface for paint.


  • Natural Fiber String. Any thin, cotton, or hemp twine will work; a variety with two or three strands twisted together is best. 3mm is perfect.
  • Elmer’s Glue. The classic adhesive we all know from elementary school works great here as well.
  • Plastic Wood. Plastic wood or putty will work here, as they are crack resistant and durable.
  • Paint. A small amount of paint is required for these jobs, although do your best to match the existing color unless you feel like changing things up and painting the entire door a new color.

The Process of Fixing Cracks in Solid Wood Doors

  1. The first step is to clean the edges of the crack. Using the utility knife and hacksaw blade, remove any burs or detritus that has built up in the gap. It is important to make sure that the wood of the panels is exposed.
  2. Measure out two pieces of string to a bit longer than the length of the crack. This extra length gives you something to hold onto as you proceed.
  3. Thoroughly soak the first piece of string in the Elmer’s glue, making sure that it is completely saturated. You may need to water down the glue if it is too thick and not being effectively absorbed.
  4. Use the tip of the flathead screwdriver to pack the string into the crack, starting at the top and working your way down. Be careful not to push the string all the way through, out the other side of the crack. It is also important to make sure your panels remain parallel and aren’t being twisted as you pack the string.Opening the door so you can easily monitor both sides is a good idea.If you find that your string is too thin or too thick for variations in different portions of the crack, you can gently twist or untwist the end to change the thickness and get a perfect fit.
  5. Repeat the process with the second string, once again being careful not to push the first string out the other side of the door. This can take a bit of finesse as you want the final placement to leave a small trough in the gap to allow your putty to lay flush with the panel.
  6. Let the glue harden for several hours to make sure it is fully cured.
  7. Once your glue is hardened, wipe the area with a paper towel to give the putty a clean surface to bond to.
  8. Use your putty knife to spread the material over the gap, making a smooth surface that is even across the affected area. Allow several hours for the putty to dry.
  9. Take your fine-grit sandpaper and smooth the area to prepare it for paint.
  10. Paint the area to match the rest of the door. Many people choose to paint the entire panel to achieve a more uniform and consistent look.

This process works best on painted doors as the filled areas will remain visible on stained doors. It will achieve the same results functionally, but it won’t be as pretty.

Step 5: Prepare the Texture Mold

If your hollow core door is smooth and flat, you are done. Prime and paint the door. But if your door has a wood grain texture, then the smooth, flat patch will still show up badly after painting. So now it is necessary to reproduce the wood grain texture prior to painting.

Find a place on the door that has no damage, where the wood grain pattern is in good shape. The bottom of the door is a good place to consider because it is typically wider than other areas, and you can create a texture mold that is wide enough to cover most damaged areas. Create a frame out of wood and secure it to the door area selected for the texture mold. Clamps or small nails can be used for this.

Use clay or putty to seal the crack between the wood frame and door to prevent silicone from leaking out.

Level the door so that the silicone settles out to an even thickness across the entire frame.

Following the manufacturer’s instructions for the RTV Silicone Rubber, mix and pour the silicone into the frame. Vibrate the door for a few minutes to help bubbles escape and to ensure the liquid silicone seeps into all of the wood grain texture lines. This can be done by banging lightly on the underside of the door with a rubber mallet.

Let the silicone cure completely. See the manufacturer’s instructions to determine how long to wait. When totally cured, remove the frame and peel up the silicone texture mold. It will not stick to the door. The mold will have a negative relief of the wood grain pattern of the door.

Things You’ll Need

Patching a Hole or Crack

  • Utility knife
  • Paper towels
  • Expanding insulation foam
  • Auto-body filler or spackle
  • Putty knife
  • 120-grit sandpaper
  • 320-grit sandpaper

Repairing a Scratched Door

  • 320-grit sandpaper
  • Wood filler
  • Putty knife
  • Damp cloth or paper towels

Repainting a Hollow Core Door

  • 220-grit sandpaper
  • Paint or wood stain
  • Broad, all-purpose paintbrush or paint roller

What you’ll need for repairing holes in doors

Here’s a list of all the tools and equipment you’ll need to repair and patch the hole:

  • Heavy gloves
  • 320-grit sandpaper and 220-grit sandpaper
  • Wood filler
  • Putty knife
  • Sponge or damp paper towel
  • Vacuum cleaner
  • Screwdriver
  • Hammer
  • Paint or wood stain
  • Paint roller

How do I fill a hole in a wooden door?

Filling a hole in a solid door can be done with wood filler. Here is a great article on repairing solid doors using filler

Additional Tips for Hollow Door Repair

Are you not sure what auto-body filler is? Ron Hazelton explains that auto-body filler is also referred to as polyester resin. This product is made from actual resin and is a catalyst to facilitate its effectiveness. That’s what makes it such a potent tool in your arsenal as you go about repairing the door.

Ron Hazelton recommends using 100-grit sandpaper, but this is up to you and how smooth you’d like the finish to be. You can also try using putty knives that are wider than the holes in the door for the best results and smoothest appearance.

If the hole is on the larger side, HomeServe advises using a piece of cardboard to fix it. Cut a strip to the right size and roll it up to fit into the hole, coming up close to the edges (the inside part of the cardboard should be hollow). Spray the foam into the hole. The cardboard will act as a good support and is stronger than paper towels.

Things You Will Need Paper towels Wood filler Sandpaper Door paint Low-expansion aerosol foam insulation Lightweight auto-body filler Spackle Cardboard Tarp or drop cloth Utility knife Putty knife Spatula Paintbrush


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