A sill tray collects any residual water and disperses it to the exterior of the building.

Aluminium window and door joinery has not changed this concept, but do rely totally on the window or door frame to be waterproof and require all water capture points to drain freely.

Window and door / wall cladding detailing at the head, side and foot of windows and doors is a critical area in the waterproofing of the exterior of the building, too often a lack of detailing sees the waterproofing of the junction between the window or door and the wall cladding fail.