My 100-year-old house has a wooden front door made of thick wood ribs interspersed with 8 wood panels, each about 10" high, 8" wide, but only 1/8" or 3/16" thick. Perhaps the door originally had glass instead, then someone replaced glass with cheap, thin wood panels?

Anyway, there's a thin (1/16" wide) but ugly crack running top-to-bottom (10" high) in one panel. From the inside I even can see a little bit of daylight on the other side on bright days, although on rainy days the crack closes up as the wood swells.

I've sanded, patched, and repainted the inside of the crack once before, using lightweight spackling compound on the inside only, but I was lazy and didn't do anything to the outside of the crack that's exposed to the elements. So after a few months of rain and hot sun, the the crack reappeared.

Both inside and outside are painted (Inside: latex, outside: not sure.) The crack on the outside is barely noticeable because the exterior side door is black, but the inside is white and the crack is very noticeable. So mostly I care about fixing the inside and want to do as little as possible outside, as long as the crack doesn't get more visible outside.

Any advice for how to patch this to withstand the elements on the outside and look good on the inside? I'm looking for advice about patching material (or materials if I have to use something different outside vs. inside) and technique (e.g. outside first? inside first? anything special to worry about given that inside and outside are only an eigth of an inch apart?)

  • You say you've already patched it but didn't say what with. Also, take a look at: diy.stackexchange.com/questions/2132/…
    – Niall C.
    Jan 3, 2012 at 1:19
  • 1
    Maybe a picture would help to see how large the crack is? If the crack is small enough, wood putty works well. If it is large, then you need something flexible, like caulk, to prevent the crack from appearing again. Other options, replace panel and/or door (which may not be an option).
    – Jon Raynor
    Jan 3, 2012 at 16:21
  • @Jon Raynor - I edited to add more info about crack width. It's under 1/16"-- very thin-- but it's highly visible against the white inside of the door, and made worse by paint on the inside peeling away from the crack. Replacing the panel or door is aan option I'd love to avoid. ;-) Jan 3, 2012 at 18:55
  • @Niall C. - I edited with more info about how I patched it the first time with lightweight spackling compound. I assume that failed because of water coming in from the other side? I looked at the other thread and wasn't sure if it covers my case where one side is exposed to the elements, and where the wood is very thin. Jan 3, 2012 at 18:58

1 Answer 1


Lightweight spackling compound is not suitable for exterior use. Even if painted, water will effect it greatly. In addition, it is prone to cracking as it is brittle and probably will not withstand opening and closing of the door (vibrations).

Wood filler or wood glue may work to fill the crack and would be better for exterior use. The glue is probably more flexible than the filler and may be better for filling the crack. I've used the wood filler before, but usually to fill nail holes or fill in small cracks. For a few bucks and some sanding, it may be worth a go round.

Another option would be to caulk the crack. Since caulk is flexible, it will resist cracking better than the wood filler. Both caulk and wood filler would be paintable. I don't think you can stain caulk, but I believe the door is painted on both sides.

The other option I mentioned in the comments is to replace the panel/door. The panel is most likely held in by surrounding trim, so if that can be removed, just the panel could be replaced.

Another option would be to get a very thin piece of veneer wood, cut it to the dimensions of the panel, and then glue it on top of the existing panel. Since you cannot see the crack from the outside, this could be done on the inside and then painted to match.

  • Glue or caulk sounds like the easiest first step to try. Which would you recommend if I had to choose? Jan 4, 2012 at 0:34
  • If both sides of the door is paintable, probably a good interior/exterior caulk as it will resist cracking better.
    – Jon Raynor
    Jan 4, 2012 at 14:15
  • Cool. Should I fill the caulk in on one side only and just wipe off anything that seeps into the other side, or should I press into both sides? Jan 5, 2012 at 16:51
  • Fill in one side, wipe any excess off the other side. Let dry, then fill in any gaps on the other side as the dried caulk will serve as a backer for the other side. Getting both sides filled in with one pass I think would be challenging as pressing one side would effect the other.
    – Jon Raynor
    Jan 5, 2012 at 16:59
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    I don't think it matters, pick a side, lay a bead of caulk in the crack, use a taper or putty knife to smooth it out, wipe off any excess, move to other side of door, wipe out any excess that has leaked though. Let dry and then fill in any voids on the other side of the door using the dried caulk as a backer from the 1st application.
    – Jon Raynor
    Jan 6, 2012 at 16:36

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