This invention relates to prefabricated trusses and, more particularly, to prefabricated trusses for use in structures such as residential and commercial buildings.
Trusses, like many parts of the structure, have been prefabricated for a number of years. The motivating factor behind the use of prefabricated trusses is to produce a structurally sound building while saving labor and materials. By prefabricating the truss, at a location other than the actual building site or other than in place, money can be saved due to more efficient use of labor, specialized machines, economy of scale, etc. Prefabricated trusses have generally taken the form of a triangle, two sides of which will define the roof surface, the third side to rest upon the top plate or king plate of the structures walls. As such, the truss is separate from and supported upon the walls with a bottom chord level with the top of the walls.
Where a wall, either exterior or interior, is designed to have an opening, typically the wall would be framed and a beam or header placed across the uppermost edge of the opening and integrated with the wall either by attachment to surrounding studs and possibly with the addition of cripple studs. The area above the header would be finished off with a sill or king plate running the length of the wall. A prefabricated truss placed on top of the wall would usually have a bottom most beam or chord that would be parallel to and lie against the king plate. As such, the truss was not integrated with the wall but rather attached at the generally linear interface of the king plate with the bottom chord of the truss.
Other prefabricated trusses may not have a bottom side or chord level with the wall but, as in the case of a scissors truss, be likewise designed to be secured to the top of a structurally complete wall.