SteveBausch - The question that mattshak33 has asked is valid and he has received good advice in another forum. Pre-Engineered buildings are often bid either with or without a foundation:
1. If a foundation is included, the building manufacturer typically hires an engineer to make the design based on the specific site.
2. If a foundation is not included, the building manufacturer will have a brief statement to the effect that a "suitable foundation" must be provided.
Many times pre-engineered buildings have uses that require quite detailed & atypical foundations, for example:
1. Sloped floors with trenches and sumps to collect spilled industrial process water.
2. Equipment pedestals for heavy machinery.
3. Embedded process piping or electrical conduits.
The building are pre-engineered, but the foundations are certainly site specific and may require custom design.