Aluminium casement windows – also called projected windows or sash windows – incorporate ‘leaves’ or ‘sashes’ that swing out from the window’s outer frame.

Casement windows can take one of two forms: top-hung or side-hung. The sashes of top hung windows are attached to the top of the outer frame with movable friction stays, thus allowing the bottom to swing-out. Whereas with side-hung windows the sash is attached either on the left or right, allowing the opposite side to swing-out.

The obvious benefit of this is to control wind, rain or ventilation to the exact degree that you like. Top-hung casement windows are probably the best solution for the weather-facing side of any building, as you can have them open without admitting any rain or severe winds. No other window can be opened as far, which can be an important advantage when you depend on cross ventilation to cool your home.

A casement window unit usually has a combination of fixed panes as well as opening sashes. (see standard configurations below) but can also be custom-designed. In the case of shopfronts or enclosures, casement window units can be built to fit seamlessly with fixed-pane windows, sliding doors or folding doors.