1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Window Sill Replacement - how to level

Discussion in 'General DIY' started by CNSam, 3 Apr 2020.

  1. CNSam

    CNSam

    Joined:
    14 Oct 2017
    Messages:
    18
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi Folks,

    So I'm in the process of replacing a windowsill in our kitchen which had basically every dent, chunk etc missing from it. It was a wooden sill which was coming away anyway.

    I have taken the sill up today and noticed that below it is basically...bricks and mortar, however the plaster line is higher than the level of the brick (see pics).

    What's going to be my best course of action here please folks? I'm thinking filling with something and levelling off or just using packing wood, but then how do I secure the new sill?

    Any help would be greatly appreciated

    Sam
     
  2. JobAndKnock

    JobAndKnock

    Joined:
    30 Sep 2011
    Messages:
    4,796
    Thanks Received:
    1,027
    Location:
    Lancashire
    Country:
    United Kingdom
    Dobs of compo (plasterboard adhesive) laid across the window opening and the window board dropped on and pressed down to the correct height and level OR two rows of packers at something like 300 to 400mm centres laid across the window opening an levelled (front to back and side to side). The window board is laid atop these, they are then drilled and counterbored before drilling through into the masonry of the wall beneath with an SDS/masonry drill (7mm drill bit, 7mm plugs, #10 or 5mm screws - often 80 to 100mm long to get through the board, packers/dabs and fix into the masonry below) and screwed down. If the wall beneath is a stud wall, then skip the masonry drill and brown plug and screw straight down. Packets can be of cuts of softwood or plywood or plastic window/door packers

    After it has set (if using dabs), or been screwed down, fill the gap beneath the window board with plaster. Screw holes in the window board can be filled with 2 pack filler and sanded flush. Note that whilst PB adhesive is normally sticky enough to hold an MDF or softwood window board on it's own, it doesn't always work, so for a belt and braces approach add a few screws drilled and counterbored and long enough to fix into the wall beneath

    Note the use of the term window board as opposed to window cill (sorry, but that's joiner-speak)
     
    Last edited: 3 Apr 2020
  3. Sponsored Links
  4. Johnny Allround

    Johnny Allround

    Joined:
    27 Mar 2020
    Messages:
    459
    Thanks Received:
    88
    Country:
    United Kingdom
    Hi Sam, fit soft wood window board and cap it ,finish off with a nice clean silicon line job done. Capping sits over existing calls when having upvc windows installed. Hope this helps.
     
  5. Johnny Allround

    Johnny Allround

    Joined:
    27 Mar 2020
    Messages:
    459
    Thanks Received:
    88
    Country:
    United Kingdom
    Not calls I meant cills.
     
  6. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
  7. Sponsored Links
Loading...

Share This Page