In old box sash windows the original panes are often only 2–3 mm thin, and at some point the first one cracks. At this property in Berlin-Zehlendorf we replaced several cracked panes: removed the old remains, cleaned the rebates of old putty and fitted new panes of 4 mm float glass, puttied and neatly struck off. Among them was a semicircular window, for which we cut a circular segment to an exact fit – the right-hand pane in the photo. The frame stays, only the glass is new: the cheapest way to get a box window tight and presentable again without touching the original.
