Why Field Information Matters
Structural engineers design based on what's actually in the building. When drawings aren't available or conditions have changed from original design, field-collected information fills the gap. The quality of that information directly affects the accuracy and reliability of the engineering.
Essential Field Information
Photographs
Photographs are the most powerful documentation tool. For structural purposes, photos should capture:
- Exposed framing members (beams, joists, columns, studs) with measurements when possible
- Connection details — how members attach to each other and to the structure
- Foundation walls or footings where visible
- Any areas of cracking, damage, deflection, or distress
- Overall room dimensions and ceiling heights
- Roof framing and existing HVAC curb or penetration locations
Label photos with compass direction, room name, and description. Include a measuring tape in framing photos for scale. Photograph in good lighting — use supplemental lighting if needed.
Framing Member Dimensions
When framing is accessible, measure and record member sizes. For steel members, note the section depth (beam height), flange width, and web thickness. For wood members, note actual dimensions (not nominal), spacing, and span. For concrete, note wall or slab thickness and rebar spacing if visible.
Floor Plan Dimensions
Measure wall-to-wall dimensions for every room, hallway, and opening in the project area. Include door and window opening sizes and locations. Note column or post locations and any existing steel beams or headers visible in the ceiling or at openings.
Story Heights
Record floor-to-ceiling heights, floor-to-underside-of-framing heights, and total floor-to-floor heights where multi-story. These drive the structural system sizing for columns, walls, and lateral elements.
Equipment Information
For projects involving equipment installation, provide the equipment manufacturer's data sheets showing weight, dimensions, center of gravity, and required mounting pattern. For RTUs, also note existing curb size and location relative to roof framing.
How Contractors Help
On most existing building projects, the general contractor or a skilled subcontractor collects field information in coordination with the structural engineer. The engineer specifies what's needed; the contractor provides the access, measurements, and photos. This is a well-established workflow on TI, renovation, and equipment replacement projects.
The key is clarity upfront about what information is needed — and confirmation that the contractor has collected it completely before engineering begins in earnest.