The base code requires that the design of your structure meet certain requirements. The code allows for a couple of ways to meet these requirements. The first method is known as “prescriptive” wall bracing, and is built into the code as prescribed building elements that must be included at specified positions of the building. Prescriptive methods are acceptable as long as the structure’s design fits within certain limitations (wall height, window size/location, etc.). The second method is to demonstrate, by engineering analysis, the forces imposed upon the structure, and the design of structural elements to withstand those forces. Whereas the prescriptive method imposes certain limitations on the design of the structure, the engineering analysis of the building allows for greater flexibility in the design, while ensuring it can withstand the actual natural forces the structure will experience.
In almost all cases, Mascord designs will require engineering analysis (not designed to prescriptive method). This analysis is required to be conducted by a professional, such as an engineer, who is licensed by the state in which the structure will be built. Furthermore, the analysis is specific to the exact building site – for this reason, we do not have “pre-engineered” plans that can be built anywhere. An engineer will need to review the plans and provide an engineering analysis report and additional drawings and specifications to go along with your plans for permit submittal. You should allow for additional time and expense to complete this process.
When the design includes retaining walls, these will also require engineering. Although the code provides for some prescriptive basement and concrete/masonry wall designs, these only work in limited situations. The use of site-engineered retaining walls allows for much greater design flexibility and ensures that the walls are designed specifically for the design loads, unique soils, fluid pressures, and drainage characteristics at the building site. It makes little sense to place the most expensive investment a family typically makes onto a foundation that is not designed for the unique characteristics of the land on which it is set.
The physical characteristics of the building site may necessitate additional analysis by licensed professionals, such as engineers, geologists, or even archaeologists. A geo-technical engineer may be required to assess the risks of ground movement and the impact of ground water on the design of the structure’s foundations, for example. These issues can be especially challenging where certain soil types are involved, or where faults, slides or other surface features are expressed. The probability/risk of things like flood, wildfire, landslide, high wind or earthquake should be considered and analysis of how to address these concerns may be required as part of your permit process. In some cases, historical preservation, ecological conservation or some other restriction may come into play. It is recommended to check with your planning department to review any known concerns, well ahead of obtaining your plans and starting your project