Sill (or cill) replacement

Discussion in 'Builders' Talk' started by mackie, Sep 5, 2021.

  1. mackie

    mackie Member

    Hi,

    I need some help / advice please.

    1950's ex-council house. Concrete exterior sill has blown as per picture. It is a 1680mm stooled sill on a 1550mm wide window opening. Someone has tried to fix it before, but that was no more than patching the front edge (you can see this on the left of the picture, I think this is what has fallen out the rest of the sill).

    I will be repalcing the window and so now is the best time to look at the sill. However I cannot seem to find a repalcement. I can find modern versions, but this will look new compared to the other sills (picture 2) and I cannot seem to find anything at a reclaimation Yard local to me (Bognor Regis, West Sussex).

    Any ideas on the best way to sort this out. Ok last resort would be to remove and replace with bricks and then the window I order have a larger uPVC cill but to me this is the last resort.

    Thanks in advance.

    Damaged.jpg

    Other.jpg
     
  2. Wayners

    Wayners Screwfix Select

    I've seen them cast in place. Make a box up along the sill and pour concrete then shape as setting.

    Other way is to use bricks along to make a sill
     
  3. mitefix

    mitefix Active Member

    Place a timber Pattress on the front secure it in place and fill it from the top building it up in layers

    Epoxyset 105 Standard Concrete Repair 4kg (toolstation.com)

    A new sill would need to be pre casted to the original shape or find and shape a concrete sill to suit.

    I have shaped them before out of pre cast concrete lintels.
     
    Last edited: Sep 5, 2021
    Wayners likes this.
  4. Truckcab79

    Truckcab79 Screwfix Select

    I’ve done both ways. Easiest is probably to make up a box mould of exactly the right dimensions and cast a new one. Don’t overlook how heavy it will be once it’s finished though. When I did my first one I was removing it from the mould when it suddenly dawned on me I was fitting it on my own and couldn’t actually lift it. :D

    Also not that difficult to cast in situ. If you want a permanent fix don’t forget you’ll need to drill and fix some supports between the two pieces. (Like rebar). Stainless steel threaded bar works well.

    Here’s one I did for a client as free ‘extra’ at the end of a kitchen refit. There was pretty much none left. Really should have come out but no money left apparently. Only charged her a tenner for materials as I was there anyway. She was made up as you can imagine compared to what she would have had to pay to get it replaced. Didn’t help that rotten frame in the picture behind it though.

    upload_2021-9-5_16-31-11.jpeg

    upload_2021-9-5_16-31-46.jpeg

    upload_2021-9-5_16-32-16.jpeg
     
    chillimonster likes this.
  5. Truckcab79

    Truckcab79 Screwfix Select

    ….and whichever route you take don’t forget to cast the drip channel underneath. Easily missed.
     
  6. mackie

    mackie Member

    Had a couple of builders out and basically it is shot. Not only has it cracked along the front edge but also from front to back (under the window). The concrete is also as soft as s…, also falling apart when poked with a screwdriver.

    Have found a local company who make concrete products and so they will make we a new sill, window is coming out anyway so will change it them.

    thanks for the advice though.
     
  7. Truckcab79

    Truckcab79 Screwfix Select

    Sounds like a good move. Trouble is, once they crack, the rebar inside gets rusty, expands and continues pushing out on the concrete making it progressively worse.
     
  8. mackie

    mackie Member

    Cill - replaced - Quiet pleased with the end result (the 3 x tape you can see at the bottom of the window is just an infill to close the gap until the new window arrives).

    Fixed.jpg
     
    Truckcab79 likes this.

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