Aspect Ratio Warning on Sliders
The uPVC industry worldwide recommends not to exceed a ratio of 2:1 where the height of the sash should not be more than double the width of sash.
The reason for this is that when the sash gets too high, relative to width, it becomes unpredictable as it slides - imagine sliding a piece of A4 paper along a table in the landscape orientation, and then compare how firm it feels when you slide it along the table in portrait orientation.
