A 40mm tongue and groove translucent polycarbonate system developed specifically for use with translucent walls. We reside in a Victorian flat with substantial draughty sash windows. Our secondary glazing arrived at 7am over the day promised, fitted into the millimetre, works perfectly, and appears wonderful. Our bedroom overlooks a railway https://trentonhztiq.thenerdsblog.com/40454691/the-basic-principles-of-secondary-window