I’m trying to find the best way to fill a hole in wood with a cavity behind it.

I’ve got a stair box which at some point in the past has had a chunk taken out of it that goes completely through the wood. Due to the fact it’s a stair box there’s a large hollow cavity behind the hole that means I can’t fill it with putty or epoxy without it easily being pushed through into the cavity.

What’s the best practice here?

EDIT: Attached Imageenter image description here


  • 2
    You're getting a lot of good guesses. You'd probably get even better ones if you'd actually included a picture of the situation, maybe even with a tape measure in it so people can see how bit a hole you're dealing with since you didn't mention that, either.
    – FreeMan
    Commented Jun 8, 2022 at 18:12
  • 1
    I agree there is not enough info in this question to come up with an intelligent answer. Please post a picture and included some measurements and you will get much better answers.
    – bigchief
    Commented Jun 8, 2022 at 20:06
  • 1
    "stair box" is somewhat ambiguous is this an arcitectural feature or a piece of furniture?
    – Jasen
    Commented Jun 9, 2022 at 5:48
  • I’ve added an image now. Apologies for any ambiguity about the term “stair box”, I think it’s a UK term. It’s a wooden “box” that covers the top of a staircase as it comes into a room. Something like this images.app.goo.gl/nQRgCmJz81MVVN678
    – martpendle
    Commented Jun 9, 2022 at 6:57
  • 1
    The picture in your question is helpful, but the images at the link still leave me (from the USA) confused. Is this some sort of hatch/box covering the top of the stairs leading to the attic? I don't understand how it covers the stairs, yet the stairs remain useable. Maybe my coffee isn't working yet this morning... Do you have access to the back side of this, even from a ladder? If so, it's an easy-peasy fix... Is that really wood or is it plaster? From here, it looks like a thick coat of plaster.
    – FreeMan
    Commented Jun 9, 2022 at 10:45

3 Answers 3


If the hole is large enough, do the standard:

"Push in a stick or two with wire or string in the middle all the way into the hole (while holding the string), then pull the stick(s) with the string against the hole, then apply patch material, wait for it to cure, cut off the strings or wires, complete the patch"

If it's too small for that, you should just be able to stuff it with putty (but it still might take two or more applications to fill it completely.)

  • Who are you quoting here? I don't understand that part, but any quote should have attribution.
    – isherwood
    Commented Jun 8, 2022 at 16:17

Maybe you don't need anything behind it. Given that we don't know how big the hole is, or even if it's on the riser or tread, try this.

Use a hole saw to round it off, slightly bigger than the hole. Using a slightly bigger holesaw, cut a circle from an appropriate piece of wood, an interference fit. If you have to make the usual hole in its centre, a piece of dowel will fill that, first. Carefully tap in the circle of wood, with wood glue round its edge, till it's flush. Stand back and admire, don't touch for several hours.

  • 1
    Any tips on how to start a hole saw without slipping when the center is already missing? I find it hard.
    – jay613
    Commented Jun 8, 2022 at 16:30
  • 2
    @jay613 - try pinning a strip of thin plywood spanning the hole. Works every time!
    – Tim
    Commented Jun 8, 2022 at 16:33

As you don't show a picture then I will be making some assumptions.

I would be doing one of the following:

  1. make the hole circular and glue in a dowel then surface to suit.

  2. screw in some screws such that they are below the surface and protrude into the hole to be filled. Use a "stiff" mix ie one that won't sag and fill then treat as needed to match the surface.

Edit, based on the picture now posted: I have repaired damage like that by drilling a hole for a dowel and once fitted then drilling the next dowel so it overlaps the first. Continue so you have a set of overlapping dowels that "lock" in to each other. Surface to suit. Once completed and painted it was indistinguishable.

  • Thanks, I like the screw idea! If I were to use dowels are you thinking glue in the edges would keep it from being pushed in?
    – martpendle
    Commented Jun 8, 2022 at 10:14
  • 1
    Once the glue dries, it will stay. If the hole is on the top, if the dowel is a loose fit, will need to hold it somehow till the glue dries. Maybe with a screw in a lager piece of wood holding the dowel.
    – crip659
    Commented Jun 8, 2022 at 10:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.