Cracked window sill repair

28 Apr 2008
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United Kingdom
I'm in the process of restoring an old sash window and I've found that the window sill is cracked. The sill is a big old lump of sandstone about 120mm thick and, as far as I can tell, the crack runs all the way through.

The way I see it I have three options:
  1. Do nothing. I don't like this option, it'll let in water and likely make the crack worse over time. Frost isn't really an issue with this house, it leaks so much heat nothing freezes.
  2. Dig it out a bit and fill it with a strong mortar mix or some premix concrete repair product.
  3. Pour epoxy in the crack. I'm not keen on this


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There's a small concern about what caused the crack, if there's an opening below that cill (another window or door) then check there hasn't been any dropping.
Assuming you're going to repaint, best bet is grind it out a wee bit (a v or groove 5mm x 5mm deep will work) then car body filler.
Thanks, it's solid masonry below the sill all the way down. The crack runs through that hole. It was full of wood which is what they used before plastic wall plugs. Who knows why that hole was drilled originally but I'm pretty sure that's what's caused the crack. Body filler isn't a bad idea though.

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