On this rear-elevation replacement project in Denbigh, cill projection is the first installation control and we set the cill projection and end details to suit the opening and surrounding finish. Kaizen Windows & Doors links perimeter sealing to opening sizes, room functions, sill heights, access and external sealing, making sure we form a continuous weather-resistant seal around the external frame perimeter, with cill projection kept as the lead check for this rear-elevation replacement scope. We also review trickle vents before making good and integrate background ventilators with the frame head, room use and internal finish where specified, with cill projection kept as the lead check for this rear-elevation replacement scope. Finally, installation access is checked so we can plan handling and working access before existing frames are removed, helping deliver rear windows coordinated around the way the adjoining rooms are used, with cill projection kept as the lead check for this rear-elevation replacement scope.