| 1 | Confirm the required clear span | Interior width without columns or interior supports | Common single-span planning widths are approximately 20–100 ft; wider buildings may require deeper members, heavier bracing, or additional engineering. | The quoted clear width must be measured between finished interior faces, not between exterior wall lines. Confirm whether roof framing, bracing, or equipment reduces usable clearance. |
| 2 | Choose bay spacing for the intended use | Distance between primary frames along the building length | Typical preliminary bay spacing is about 20–30 ft. Longer bays can reduce the number of frames but generally increase member forces, purlin requirements, and connection demands. | Check vehicle turning areas, storage racks, crane runway locations, wall openings, and whether the selected spacing matches the supplier’s structural design. |
| 3 | Set the eave height from actual clearance needs | Vertical height at the sidewall eave | Common low-rise planning heights are approximately 12–24 ft. Allow additional height for insulation, lighting, ventilation, doors, and equipment movement. | Confirm the clear height below framing, not only the nominal eave height. Account for roof slope, suspended services, sprinklers, and required maintenance access. |
| 4 | Calculate roof and floor loads correctly | Dead, live, snow, rain, wind, seismic, and equipment loads | Typical roof live-load provisions in many low-rise applications may start around 20 psf, but the governing value depends on the adopted building code, occupancy, geometry, and local conditions. | Request a written load schedule. Snow drift, unbalanced snow, ponding, suspended loads, solar equipment, and rooftop units must be evaluated separately where applicable. |
| 5 | Check wind design inputs | Basic wind speed, exposure, enclosure classification, and internal pressure | Wind speeds vary significantly by location and code edition; many U.S. design jurisdictions use mapped ultimate wind speeds of approximately 90–150 mph for common building categories. | Use the site-specific code wind speed and exposure category. Verify door and wall openings because large openings can change internal pressure assumptions. |
| 6 | Review cold-formed steel design compliance | Member strength, local buckling, distortional buckling, connections, and bracing | Cold-formed steel structural members should be designed and checked using the applicable edition of AISI S100 or the governing local standard. | Ask for design calculations or a sealed structural package identifying material thickness, yield strength, effective section properties, limit states, and connection design assumptions. |
| 7 | Specify roof slope and drainage requirements | Roof pitch, gutters, downspouts, valleys, and drainage paths | Common metal-building roof slopes are approximately 1:12 to 4:12. The selected slope affects headroom, snow behavior, drainage, and exterior height. | Verify minimum drainage slope, roof-panel requirements, overflow provisions, and whether valleys or parapets create concentrated snow or rain loads. |
| 8 | Coordinate doors and large openings early | Opening width, opening height, jamb location, and header requirements | Personnel doors are often about 3 ft wide × 7 ft high; vehicle doors commonly range from approximately 12–24 ft wide, depending on equipment and access needs. | Confirm rough openings, framed opening dimensions, door reactions, wind exposure, and clearance from corner posts, bracing, and adjacent bays. |
| 9 | Match the foundation to the building reactions | Anchor bolts, uplift, shear, bearing, slab thickness, and soil capacity | A common preliminary slab-on-ground thickness may be about 4–6 in, but footings, piers, thickened slabs, and reinforcement depend on soil and structural reactions. | Obtain column reactions and anchor-bolt plans before pouring concrete. Confirm geotechnical conditions, frost depth, drainage, settlement risk, and local foundation requirements. |
| 10 | Plan for future loads and modifications | Cranes, mezzanines, solar panels, insulation, partitions, and suspended equipment | Future additions can introduce concentrated loads well above ordinary roof loading. Design allowances should be stated in psf, plf, or point loads, not described only as “heavy duty.” | Identify future loads before fabrication. Do not attach equipment, hoists, mezzanines, or solar systems to primary or secondary members without a qualified structural review. |