Measuring the outer window sill
1. Measure the length of the window sill
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.
2. Measure the depth of the window sill
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.)
Measuring the interior window sill
1. Measure the length of the window sill
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
2. Measure the depth of the window sill
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
