In this post, we will cover how to change a window sill. This is a job that many DYIers are scared to undertake as it seems much more complicated than it is. Rest assured, even a beginner can change a window sill in a couple of hours.
MATERIALS & TOOLS REQUIRED
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Materials
Tools
- Hand saw
- Hammer
- Chisel or thick screwdriver
- Crow bar
- Tape measure
- Pencil
STEP 1: PREPARE THE WINDOW SILL
To prepare the window sill, remove any trims you may have around the board to fully expose it. If your window sill has no trims, skip this step. You can remove the silicone around the window sill at this stage if you like but this isn’t essential as you can do this after the board has been removed too.
STEP 2: REMOVE THE EXISTING SILL
Depending on the type of window sill you have, it may be going slightly under the wall on the sides. It should go almost right back to the window frame. The existing sill has probably been nailed or glued down.
The easiest way to remove it is to use a saw to cut it into pieces. First, cut it roughly in half.
Next, if your sill tucks into the wall, cut the board again fairly close to the wall and use a claw hammer to rip the middle section out.
Now you need to chisel out the little bit of sill left under the wall. This is likely to be pretty tight because it might have been plastered around. Use a hammer and chisel to knock it out. Try to be gentle to minimise the damage to the wall.
Note that your sill may not go under the wall at all but be a more modern one that just lays in the window frame. In this case, you don’t need to chisel anything; just cut the board in half and rip the halves out.
Repeat on the other side of the wall.
STEP 3: ATTACH A NEW SILL
When you buy a new sill, it is unlikely to be the exact size you need. The first step is to cut it down to your required size. The easiest way to do this is to lay your old sill pieces on top of the new sill and trace the rough shape you need. You can then adjust the measurements by using a tape measure and measuring your actual window. If you are still in the market for a new sill, check out this article on pros and cons of veneer MDF and solid wood sills.
Once the sill is ready, simply slide it into place. If your sill goes under the wall, it will be quite a tight fit.
To attach the sill, traditionally, they are nailed into the wooden blocks underneath. However, if you don’t want to have any visible nails, you can glue the sill down using something like ‘No Nails’.
The last step is to clean up the damage on the wall by using some general filler. You can go ahead and paint or stain the sill as required.
