In This Series
In simplest terms, a rough opening (RO) is a hole in a framed wall for a door or a window. Most door and window manufacturers provide RO dimensions and we build ROs to those sizes. But rough openings are a lot more than that. Whenever wall framing is interrupted for an opening, the structural functions of the wall frame must be accomplished by the RO framing.
The wall framing transfers the weight of the house down through the frame. Studs, the vertical members in a wall frame, are primarily responsible for that duty. When we remove studs for a door or window, those vertical loads must be redirected around the opening. We accomplish this with horizontal framing members called headers that act as beams that span the openings. Headers then transfer the loads to vertical framing supports—known as king studs and jack studs—on the sides of the opening. (Jack studs are also referred to as trimmers.) If the opening is for a window, we install a rough sill between the jacks and the short studs known as cripples below the sill. (Short studs used above a header are also referred to as cripples.)
The other structural functions of a rough opening are more subtle but no less important. We frame house walls to resist lateral loads and shear forces from wind or seismic activity. A wood frame skinned with properly attached sheathing offers good lateral resistance, but the framing around an RO must be able to offer the same resistance. In special cases such as high-wind areas or in active seismic zones, you may need to beef up RO framing or limit the number of openings. This article will walk you through the basics of laying out and framing basic rough openings.
Objective:
To demonstrate the process of laying out and building rough openings for doors and windows.
Prerequisite Skills:
- Basic understanding of stud-wall framing.
- Ability to read and take dimensions from basic floor plans.
- Familiarity and basic skills with power saws.
- Familiarity and basic skills with pneumatic framing nailers.
- Familiarity and basic skills with routers.
Tools:
Measuring tape, rafter square, hammer, pneumatic framing nailer, circular saw, router
Vocabulary:
Rough opening (RO): Framed opening into which a door or window fits.
Plate: Horizontal framing members at the top and bottom of a wall that the studs nail to.
Jack stud: Vertical framing members that flank each side of a rough opening and support the header. These are also know as trimmer studs in many parts of the country.
King stud: Full height vertical framing members that the jacks attach to.
Header: Horizontal framing member that forms the top of the rough opening. May be structural if the wall with the opening is a supporting (load bearing) wall.
Cripple: Short studs that fill in under a rough sill.
Rough sill: Horizontal framing member at the bottom of a window RO, often doubled.
Sheathing: Typically plywood or OSB that is fastened (usually nailed) to the framing; provides shear strength to the wall frame and a nailing base for exterior siding and trim.
Centerline: Horizontal midpoint of an opening, usually designated with a CL.
