Before you order and install your new window sills, you need to determine the correct window sill size. This is made simple with our step-by-step measuring guide.
What do you need?
Open your window and measure the entire width of the wall opening. If your window sill extends into masonry then please add the length of this extension to your final measurement.
Now determine the depth of your window sill. Measure from the front edge of the wall opening (the area where the window sill will rest on the masonry) to the window frame. You will also need to add 30-40 mm. This overhang protects your facade from water.
Example: 1000 mm (3.) + 40 mm (4.) = 1040 mm (1.)
Please measure the entire width of the wall’s opening before subtracting 5 mm from this measurement for installation allowance. If you want to install your new window sill into the masonry, please ensure that you account for the amount of the sill that you wish to have extend into the wall.
Example: 1000 mm - 5 mm = 995 mm
The depth of the window sill should now be determined. To do so, please determine the distance from the front edge of the extending masonry that the window sill will sit on, to the window frame. Now add 10-20 mm to this measurement. This is for the part of the window sill that will be embedded below the window. If you want an overhang for aesthetic reasons, now is the time to add the desired depth (30-40 mm is the standard).
Example: 1000 mm + 10 mm = 1010 mm
