Replacing rotten window sill

Discussion in 'Wood / Woodwork / Carpentry' started by Keitai, 10 Oct 2020.

  1. Keitai

    Keitai

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    Got a replacement piece of wood for a rotten window sill. It's 45mm thick and a few cm wider than old piece. I was just gonna plane it down to right thickness. Regarding the mitred angle would definitely be just be 45 degrees ( which would mean just cutting it with chop mitre saw) or do need to scribe it in somehow? 16023201441105493067413022332709.jpg
     
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  3. If you can take the side bits (there's probably a proper name for them) looks like you won't have to. Is the chamfer of the new wood the same as the old?
     
  4. wgt52

    wgt52

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    Me thinks you are brave if you're not used to wooden windows and working on them.

    So how much of the cill is needing replacement?
    Is the window light (sash?) fixed or hinged?
    Is the cill separate from the casement? If it is do you know how it is fixed?

    Yes the corner should be a simple mitre at 45 degrees.
    Once you have the replacement sized to match don't forget to create the 'Drip' grove.

    When fixing you will need waterproof glue. And probably 2pack filler.

    Good luck
     
  5. It looks to be separate.
     
  6. KenGMac

    KenGMac

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    Must admit, i am with EddieM, It looks like that sill is a so called Planted sill meaning the external sill appears to have been retro-fitted to the rest of the sash?

    As an aside, for longevity, the new sill would have been better if it were treated? OR??? is it treated timber??
     
  7. Keitai

    Keitai

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    It's just the small end bits which need replacing. Top and bottom. I've used untreated wood. I planed it down to thickness and will paint sadolin wood stain over it. The mitre cut seems a bit off as I used the old one as a template. Was going to screw and use sticks like **** to hold it in. I guess get external brown silicon too.

    How do I cut a new drip groove? Hand saw?


    20201014_142048.jpg 20201014_143435.jpg 20201014_150730.jpg
     
  8. troutybrown

    troutybrown

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    Put a groove in with a router
     
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  9. Keitai

    Keitai

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    Cant seem to get this piece in. Feels jammed. Can u see the big gap where I'm trying to push it in. Shall I just put silicon ro cover that? 20201014_155948.jpg
     
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  11. KenGMac

    KenGMac

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    Two possibilities instantly?

    Check to see that the remnants of the old sill are totally removed.

    Most likely is that the new sill is just a small amount too long? in that you are holding the Miter to get it to mate as well as you can but the overall length of the sill is jamming as you offer it into place? to check, slide the sill in but keep the end nearest the wall actually rubbing on the wall??

    Ken.
     
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  12. Burnerman

    Burnerman

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    It looks like the insert is tight where your thumb is, but whatever you do the mitre is going to have a gap :(
    I think you’re a bit tight at the wall too - and that bit is easy to sort with silicone.
    (Unless this is your property, think hard before getting involved with stuff like this!)
    John :)
     
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  13. wgt52

    wgt52

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    You need to ease the end where the new cill butts up against the brickwork.

    But before you fix the new planted cill some preparation.
    Make sure the casement (that is the main window timbers) is clean and and I'd treat the bare timber with Cuprinol 5* wood treatment. Any timber in the newly exposed casement that is soft should be treated with a wood hardener. Make sure the top of the wall is free of dust and rubble. Is the casement bedded onto mortar? if so then the planted cill probably needed to be also (but you could point that up afterwards).
    I'd drill through the casement to the inside the house to fix the planted cill with screws from the inside. You can always hide the screw heads by increasing the hole inside to take the screw head and then fix or plug.
    Use waterproof glue to help the fixing.

    Drip grove needs to be 1/4 to 5/16 inch wide and a similar depth.
     
  14. Keitai

    Keitai

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    Why do you say think hard about doing this kind of thing? The old sills are rotten out and pull out. I could just push them back in and tell them to get a specialist window company out on which case it's the same as doing nothing or put these two replacements bits and charge considerably less than a window company. What could go wrong?

    The whole window sills will need replacing anyway properly soon.

    Are you saying I could be sued? If so, I won't continue
     
  15. Keitai

    Keitai

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    Screenshot_20201015-104849_Gallery.jpg Screenshot_20201015-104919_Gallery.jpg
    Don't think it was cemented in. Think it was screwed into the wood on top of the render.

    Wood hardener. I'll get some. What a palava.

    I've got window wood sealant as well.

    Not totally sure how I'll drill through from the inside to be honest. It does seem like the previous guy just screwed in from the front
     
  16. KenGMac

    KenGMac

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    The times I have undertaken this type of repair [OK A very long time ago?] I have screwed from the outside, this because you will have more control over the placing of the screws and overall positioning of the sill when fitted / being fixed.

    Ken.
     
  17. Burnerman

    Burnerman

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    No, I'm not saying it's hard to repair, just that it won't last any great length of time and after a year or so the punter may not be too chuffed!
    This needs to be explained before the job commences, that its a bodge and little else.
    I've done a few repairs like this, you never earn what the job is worth and you're just postponing the inevitable - so I don't bother anymore.....if they can't afford a window replacement then it's not my problem.
    Getting less soft in my old age!
    John :)
     
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