For this dual-colour windows project in Longridge, opening checks, frame fitting and finishing are treated as one sequence. Cill Projection leads the review, so we set the cill projection and end details to suit the opening and surrounding finish, with cill projection kept as the lead check for this dual-colour windows scope. We use internal sealing and external making good around internal finish, external finish, trims, sealant colours and adjoining decoration, ensuring we close the internal frame perimeter cleanly before trims or making-good work is completed and finish external reveals, render or masonry interfaces around the installed frame, with cill projection kept as the lead check for this dual-colour windows scope. The last technical check is reveal dimensions; we check internal and external reveal depths so trims, plaster and handle clearances can be coordinated, with cill projection kept as the lead check for this dual-colour windows scope. This supports frame finishes coordinated separately to the interior and exterior appearance.