Field of the Invention
The present invention relates generally to structural elements for a building, and more particularly to a device, method, and system for framing openings in building walls.
Description of the Related Art
Buildings, such as houses and other structures, are commonly constructed of frame-constructed walls that separate the inside of the building from the outside, and that separate rooms from one another, as well as that support a roof and possibly upper floors of the building. The frame-constructed walls are formed by so-called stick members, which include vertical studs, horizontal wall plates, and horizontal load-bearing headers or lintels over portals, doors, windows and fireplaces. The stick members for a stick-built wall may be of wood, steel, or other materials. The frame-constructed walls serve as a base for wall coverings, such as wallboard, siding, wall sheathing, etc.
The walls typically have openings for doors and windows, for example, that are formed in the wall and provided with framing that forms a rough opening for the window or door and that supports the window or door in the wall. In one example, a framed rough window opening has a vertical king stud on each side of the opening extending from the bottom or sole plate of the wall to the top plate of the wall structure. Vertical jack studs are provided below the window opening and vertical cripple studs are provided in the wall above the window opening. Horizontal members of the rough window opening include a sill at the bottom of the window opening and a header or lintel extending horizontally across the top of the opening. Vertical trimmer studs are provided on the sides of the opening extending from the sill to the header or from the sole plate to the header. Doors may be framed in the same way but without the use of a sill and jack studs that form the wall below a window.
Every structural opening of a standard stick-built structure requires at least two king studs, two jack studs, and one header. Typically, these three elements are constructed using solid virgin lumber, the construction of which requires multiple calculations and cuts by the contractor, resulting in pieces of scrap wood and using valuable time. These calculations are based off of the expert knowledge that the professional construction worker has gained. Following this process, the three elements are commonly nailed together to form the opening. In the majority of new construction, walls are framed flat on the floor and then stood up and set in place. With this form of framing, doors and windows are laid out first.
The process of remodeling, although different, also places a major focus on the importance of structural openings. With the top plates and sole plates already installed, studs are cut and installed vertically, to create new openings.
In both cases, the king studs are installed first. The king stud is the piece of lumber that runs from the bottom plate or sole plate of the wall (a horizontal piece of wood usually 1.5 inches thick that acts as the base of the wall to which vertical pieces may be attached) to the top plate of the wall (a horizontal piece that runs parallel to the sole plate that forms the top of the wall). In most states, building codes require that the top plate is to be doubled, making it a total of 3 inches thick. The purpose of the king studs is to uphold the structural integrity of the stud wall and to hold the header in place laterally. King studs can be purchased in pre-cut lengths for standard ceiling heights. For example, for a ceiling height of 8 feet (96 inches), a pre-cut king stud is 92⅝ inches in length. This accounts for a 1.5 inch thick sole plate and a 3 inch top plate. This same calculation is applied to ceilings that are 9 feet and 10 feet high.
Second components of a structural opening are the jack studs (also called trimmers). Jack studs are cut and nailed at the inside surfaces of the king studs relative to the wall opening. The jack studs also rest on the sole plate of the wall. The jack studs are responsible for carrying the header and for distributing the bearing weight that the header carries, down to the base plate, ensuring structural stability. The jack studs are typically cut on the job site, and are measured depending on the door, window, or opening height. For example, for a 6 feet, 8 inch (80 inch) tall door, the jack studs are cut to 80.5 inches and installed on the sole plate. It is common knowledge to construction professionals that in order to fit a 6 feet 8 inch door, the opening in the wall must have a height of roughly 82 inches. The same calculation applies to doors that are 7 feet tall and 8 feet tall. Both jack studs and king studs of a typical building structure are formed of flat pieces of conventional lumber.
The final component of the three components of a structural opening, according to certain embodiments, is the header. The header can be described simply as the structural piece that spans the opening formed by the jack and king studs. The header is placed on top of the jack studs. Whatever weight the header bears is therefore transferred to the jack studs and down to the sole plates. The header is typically placed directly under the top plate, between the two king studs, and bearing on the two jack studs. The amount of weight that the header bears can vary as it is responsible for supporting the weight of the ceiling, as well as any floors above. The load can often determine the height, width, and composition of the header. Headers are normally built using solid conventional lumber. However, headers can also be of engineered materials, sometimes including sandwich structures of steel or plywood depending on the structural strength required. If the only bearing responsibility for the header is to support sheet rock or other wall portion above the header, a hollow header may be used to reduce cost and save material. Headers are easily manipulated and can also be insulated in order to increase the R-value (insulating value) of that area of the building structure. The R-value is the ability of a given space to resist heat flow. A high R-value means less escaping heat or influx of heat when an air conditioner is in use, which can lead to increased savings on energy bills.
The typical necessary dimensions (especially width) of the header are also common knowledge to house construction professionals, for example. The two 1.5 inch jack studs must be accounted for. For a 24 inch wide door, which requires a rough 26 inch wide opening, the header must be cut to 29 inches. When the opening is much larger, it is common for two jack studs to be used on either side of the opening. As a result, the length of the header must account for an added 3 inches on each side, for a total of 6 inches of additional length.