Rough Opening (Ro)

What is a Rough Opening (Ro) ?

Definition of Rough Opening (Ro) in Construction
The rough opening, is the full untrimmed opening for a window or door. The rough opening, like the masonry opening, will be calculated to allow the proper installation of the door or window, with shim space allocated to allow adjustment. Normal shim space can be as small as 1/4 inch, to as large as 1 inch on either side of the opening. The rough openings in a structure are necessary during the construction of the structure. It is imperative that the framer, mason, concrete sub, etc. all be provided the correct rough openings for all the doors, windows or other assemblies that will be installed within the exterior walls of the structure. The rough openings are also required for horizontal construction such as concrete slabs and roof decks for items such as roof hatches or elevator pits. It is very important that a contractor accurately research the rough openings required for all elements of the project. Substantial delays can occur in a construction project if the rough openings are not readily available or are incorrect and the structure is built according to incorrect rough opening dimensions. Most window and door catalogs will provide the specific rough openings required to accommodate their windows and doors. This information must be accessed to allow the mason to anticipate their coursing and the framer to frame the openings in the structure correctly.