Prescriptive vs. Engineered

PRESCRIPTIVE APPROACH ( also called "conventional light frame construction") :
The building codes provide details and specifications to build without involving a professionally licensed engineer or architect, if within certain dimensional and building shape limits, for conventional light wood frame construction. Wall framing, nailing, sheathing, foundation details, lumber spans and many other elements of construction are "prescribed" by the codes, so engineering calculations are not required (except for the truss package, which is automatically engineered by the truss fabricator as part of their manufacture). Most of our plans meet the prescriptive requirements of the International Residential Code.

 

ENGINEERED APPROACH:
We have a few plans in our collection which exceed dimension and shape limits for the "prescriptive approach" so they were engineered by our consulting engineer. In using the "engineered approach" as an alternative the engineering calculations are required by the building code to demonstrate structural soundness of the building design for roof structure, floor beams, and/or wind load & seismic (earthquake) lateral calculations. Our consulting engineers are registered in certain states. Because engineering licensing is state-by-state the engineer's calculations are provided for reference only and are not stamped and signed. These plans may or may not require review and wet stamp by a professional engineer or architect licensed in your state. You can call your local building department or inspector to find out what is required in your jurisdiction. For example, rural or agricultural zones in many states often accept these plans without stamp and signature.

Most locations in the US accept or recommend the prescriptive approach in these types of structures. However, a very few jurisdictions accept only state licensed engineer or architect sealed (or "stamped") plans due to local conditions or unusual policies.