As the masonry is erected, reveals are created to form the hard edges of door and window openings. These reveals are vertical breaks in the masonry that form part of the structural openings for windows and doors within the shell of the building. The exact size of the openings are made either to measurements on the plans, or to the measurements on the window schedule, if one is available. If the openings are made to the sizes on the plans, the window company can measure the exact size of the openings once the lintels are installed. These openings can vary in width and height throughout a building, to add variety to the overall appearance of the build. Windows come in many different shapes and sizes, and the structural openings must be made to accommodate them. One critical element regarding the installation of windows is the height from the sill of the window to the finished floor. In the event that the window is designated as a fire escape point, the top of the sill from the finished floor must fall somewhere between 800mm and 1100mm. This allows for appropriate fire escape access as well as ensuring the window ledge is not so low that a danger of falling is present.  

External doors come in a range of standard sizes and so the structural openings sizes are likely to remain the same between jobs. For example, the typical structural opening size required for an external door measuring 1981mm x 762mm is 2100mm x 900mm, when considering the thickness of the frame. This opening size allows give the frame room to be adjusted and shimmed if required, with this size remaining fairly typical between projects. Windows on the other hand are available in an even larger array of sizes, as well as the option being available for custom sized windows to be created. The structural opening sizes for these are often denoted on the drawings and are unlikely to remain the same between different projects. As always, it’s imperative to check the drawings and schedules for the correct opening sizes to avoid costly mistakes.   

Large sliding or bifold doors are also very popular in modern construction, especially as a part of extension works. These doors typically span the full width of the rear of the extension, with only a small reveal either side. They also reach almost full height from floor to ceiling, with only the depth of the structural steel or lintel above them visible in the room.  

Different options for glass styles are available, often specified on the drawings. Whilst regular clear glass is standard in most scenarios, obscured glass may be called for in terms of creating privacy.