I live in an ancient apartment and last night I leaned on the window sill only to cause small cracks in the wood and paint to appear, as you can see in the photo.

enter image description here

What would you recommend for cosmetically repairing the cracks? I don't care to replace the sill completely right now.

  • 1
    Like what was posted in the answer it looks like this sill is about to break off completely. Could you post another picture from the front corner view of the window sill so we can see what is on the wall just under the sill? Sometimes a skirting trim or board is installed under a sill like this to help support the sill. If there is not one there you may want to push up the cracked sill and install a skirting board to help support the sill. Do this before trying to fill the crack with any kind of filler. With any luck this re-work may keep the crack closed up.
    – Michael Karas
    Dec 1, 2015 at 13:23
  • So underneath the sill there are some metal clips drilled into the wall providing support so the whole thing is more stable structurally than it looks. Dec 2, 2015 at 8:53

2 Answers 2


Any wood filler that cures will be fine. (Avoid things labeled "non hardening"... these sometimes have "putty" in the name.) Sand it smooth (120 grit sandpaper, with the grain), then try your best to match the paint.

That does look like it's about to break off, though. Don't lean on it any more.


you have probably started a crack that hasn't quite completely broken through. the below process works quite well for this sort of thing.

1) support the sill with something below it. this will prevent further movement.

2) get yourself a glue syringe from a place like lee valley tools. inkjet refill syringes work fine as well. use the largest syringe needle that is in the kit.

3) get a drill bit to match the syringe needle diameter

4) drill holes every 1" or so along the length of the crack to a depth just short of the full depth of the board

5) fill syringe with woodglue and inject into the crack. you need to insert the needle into the hole to make a tight seal with the hole. the goal is to squeeze glue in and have it spread into the adjacent crack that the hole straddles. you may need to thin the glue with water a little to achieve injection. you will just have to experiment. ideally, the glue will ooze out of the crack on either side. do every hole.

6) let dry, sand, fill, sand again and then repaint


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