If you are planning a build, a renovation, or dealing with a structural problem, knowing when to bring in a structural engineer makes the whole project easier. A structural engineer evaluates loads, materials, and codes so the structure is safe, durable, and code-compliant. Engaging one at the right milestones, rather than as a last resort, smooths permitting and reduces surprises.
What a Structural Engineer Actually Does
Before the milestones, it helps to understand the role. A structural engineer:
- Evaluates loads (dead, live, wind, snow) and how they flow through a building
- Sizes beams, columns, slabs, foundations, and connections
- Verifies compliance with building codes and local amendments
- Reviews soil conditions and geotechnical reports
- Produces stamped drawings and calculations for permits and construction
- Performs inspections, assessments, and forensic investigations
- Advises on reinforcement, repairs, and retrofits
In short, a structural engineer turns design intent into buildable, safe, code-compliant solutions.
Milestone 1: Concept and Feasibility
The earliest point to bring in a structural engineer is during concept planning, where the decisions have the widest consequences.
- Identify structural systems that suit the project (wood vs. steel vs. concrete)
- Test spans, grid layouts, and column spacings against your program
- Anticipate foundation needs based on site conditions and topography
- Flag constraints early: height limits, snow loads, wind exposure, floodplain
- Provide preliminary sizing to inform architectural massing and MEP coordination
Early input reduces redesign later. If your project involves long spans, open floor plans, heavy equipment, or complex geometry, involve an engineer as soon as you have a basic brief.
Milestone 2: Schematic Design
Once the concept gels, schematic design turns ideas into preliminary plans. This is a prime moment to involve a structural engineer if you have not already.
- Establish a clear structural grid and load paths
- Select primary materials and framing strategy
- Determine floor and roof systems and preliminary member sizes
- Consider lateral systems (shear walls, braced frames, moment frames)
- Coordinate with the architect for penetrations, stair openings, skylights, and mechanical chases
Getting the skeleton right at this stage avoids conflicts later, like a beam running through planned ductwork.
Milestone 3: Design Development and Permitting
Most Wisconsin municipalities require stamped structural drawings for a permit once a project steps outside the prescriptive code tables. At this stage a structural engineer will:
- Provide sealed drawings and calculations
- Demonstrate compliance with local building codes and snow and wind loads
- Coordinate with geotechnical reports for foundation design
- Address thermal bridging considerations that intersect with the structure
- Respond to plan review comments from building officials
Plan review usually involves at least one round of comments. Having an engineer engaged reduces the back-and-forth. There is more detail in our guide to what structural drawings and calculations a building permit needs.
Milestone 4: Due Diligence Before Buying or Renovating
If you are purchasing property or planning significant renovations, a pre-purchase or pre-renovation structural assessment tells you what you are actually buying.
- Reviewing visible structural elements (framing, columns, foundations)
- Assessing cracks, deflection, sagging floors, or out-of-plumb walls
- Evaluating past modifications for load paths and code compliance
- Considering future plans, such as removing a wall or adding a second story
- Describing the scope of reinforcement or repair the structure would need
This is a different service from a home inspection — see what to expect from a structural engineer inspection for how the two differ.
Milestone 5: Pre-Construction and Bidding
Before breaking ground, or before requesting contractor bids, a structural engineer can finalize the details that otherwise turn into extras.
- Produce detailed drawings and specifications
- Review shop drawings and delegated design elements (trusses, steel connections, precast)
- Clarify tolerances, camber, and erection sequences
- Coordinate embeds and anchor bolts with other trades
- Answer bidder RFIs to reduce ambiguity
With a complete structural package, contractors can price accurately from the same set of documents.
Milestone 6: During Construction
Even with complete drawings, questions come up in the field. Construction support is a core part of the role.
- Reviewing Requests for Information (RFIs)
- Evaluating substitution requests and value engineering proposals
- Inspecting critical work (rebar placement, structural steel, welds, anchors, framing)
- Addressing unforeseen site conditions such as poor soils or unexpected utilities
- Approving field fixes for conflicts or tolerances
- Issuing revised details and addenda as needed
Milestone 7: Renovations, Additions, and Wall Removals
Renovation projects often carry structural implications. Any time you alter a load path, an engineer should be involved.
- Removing or resizing a load-bearing wall
- Adding a second story, dormer, or heavy rooftop equipment
- Converting attics or basements into living space
- Opening floor plans or adding large window and door openings
- Adding decks, balconies, or exterior stairs
- Retrofitting for wind resistance
- Changing floor loads, such as a change of use from storage to assembly
The engineer determines whether new beams, columns, footings, or shear walls are required, designs the reinforcement to meet code, and advises on sequencing to keep the structure stable during construction. There is more on this in our guide to structural considerations for home additions and renovations.
Milestone 8: Signs of Structural Distress
If a building shows signs of movement or distress, do not wait. An engineer can diagnose the cause and design the repair.
- Stair-step cracks in masonry or widening drywall cracks that reappear after patching
- Doors or windows that stick, suddenly misalign, or will not latch
- Noticeable floor sagging, soft spots, or bouncing
- Bowed or leaning walls, out-of-plumb framing, or tilting chimneys
- Water intrusion at foundations or chronic dampness in crawl spaces
- Corroded steel, rotting wood, insect damage, or spalling concrete
- New cracks or separations after a storm
An engineer can distinguish cosmetic issues from genuine safety concerns and help you prioritize what to address first.
Milestone 9: After Storm, Fire, or Impact Damage
Following high winds, heavy snow, flooding, fire, or a vehicle impact, a structural evaluation establishes whether the structure was compromised before anyone re-occupies or repairs it.
- Visual safety assessment
- Detailed structural evaluation documented for an insurance claim
- Temporary shoring or stabilization design
- Repair or retrofit design to restore capacity and meet current codes
- Documentation for the authority having jurisdiction
This is forensic engineering and damage investigation. If an insurance claim is involved, you can hire your own structural engineer to document the damage — note that an engineer evaluates damage, while a claims adjuster determines coverage.
Milestone 10: Special Structures and Loads
Some projects involve unusual loads or site conditions:
- Retaining walls, shoring, and slope stabilization
- Rooftop solar arrays and battery systems (added dead loads, wind uplift)
- Heavy equipment, balconies, or hot tubs
- Long-span roofs, cantilevers, and transfer girders
- Foundation underpinning and helical piles
- Mezzanines, equipment platforms, and machinery support
- Agricultural buildings and utility support structures
What to Look For in a Structural Engineer
The one thing that is not optional is the license. In Wisconsin, structural drawings submitted for a permit have to carry the seal and signature of a licensed professional engineer, and that license is issued to a person, not a company. The principal engineer at Curva Consultants holds Wisconsin PE License No. 47224.
Beyond the license, what makes the working relationship go well:
- Familiarity with local codes, soil conditions, and the permitting offices you will be dealing with
- Experience with your materials — wood, steel, concrete, masonry
- A clear list of the drawings, calculations, and meetings included in the scope
- Construction administration support, so questions in the field have somewhere to go
- Straight answers about risks and unknowns rather than reassurance
Useful questions at the start of a project:
- What are the likely load paths and lateral systems here?
- What are the biggest structural unknowns?
- What assumptions are being made about the soils and the existing conditions?
- How will changes or field conflicts be handled?
How to Make the Engineering Go Smoothly
- Bring the engineer in early — early collaboration reduces redesign and delays
- Share complete information: existing plans, photos, surveys, and geotechnical reports
- Define the scope clearly and agree on deliverables and milestones
- Decide on materials up front — switching from wood to steel midstream triggers redesign
- Coordinate with the architect and MEP so conflicts get resolved on paper, not on site
- Plan for inspections at critical stages: foundations, framing, steel
- Ask about standard details that can be reused where appropriate
Red Flags That Mean You Should Call Now
- Rapidly widening cracks or sudden movement after a storm
- Sagging floors or visibly deflecting beams
- Repeatedly sticking doors and windows that suggest shifting
- Water undermining foundations or erosion near retaining walls
- Structural elements that were removed at some point with no documentation
- Significant rot, insect damage, or corrosion
- A second story or roof plan added to a structure not designed for it
Bringing It All Together
Knowing when to involve a structural engineer is about matching expertise to the moments in a project where it changes the outcome. Involve one early for concept and schematic design, bring them into permitting, lean on them during construction, and call immediately if you see distress or after storm or fire damage.
Structural Engineering in Northeast Wisconsin
Curva Consultants provides structural design, stamped drawings and calculations, structural assessments, and damage investigation for residential, commercial, industrial, and municipal projects, working in wood, steel, concrete, and masonry.
Offices are in Green Bay and Manitowoc, with regular work in De Pere, Ashwaubenon, Allouez, Howard, Suamico, downtown Green Bay, the Appleton area, and the Sheboygan area.
If your project is approaching any of the milestones above, get in touch or call 866-455-0155. A full list of services is on the structural engineering services page.
Frequently Asked Questions
What does a structural engineer do, and how do they support a project?
A structural engineer analyzes loads, designs beams, columns, foundations, and lateral systems, and confirms code compliance. They coordinate with geotechnical reports, produce stamped drawings and calculations, and provide site observations. Involving one early reduces redesign and avoids conflicts with mechanical and electrical work.
When should I involve a structural engineer during planning and design?
At concept and schematic design, to set grids, spans, and lateral systems, and again at design development and permitting to produce sealed plans and calculations. Early involvement streamlines approvals and prevents rework by aligning the structure with architectural intent, site conditions, and local code.
Do renovations or wall removals require a structural engineer?
Renovations that alter load paths generally do — removing load-bearing walls, adding a second story, large window or door openings, rooftop equipment, or decks. The engineer verifies capacity, designs new beams, columns, and footings, and specifies sequencing and temporary shoring so the work can be done safely and pass inspection.
What signs of structural distress mean I should call an engineer?
Stair-step masonry cracks, widening drywall cracks, sagging or bouncy floors, sticking doors or windows, bowed walls, tilting chimneys, chronic foundation dampness, rot, corrosion, or spalling concrete. After a storm, flood, or fire, an engineer can assess safety, design stabilization, and guide code-compliant repairs.
How does a structural engineer help with permits and construction?
For permits, the engineer prepares stamped drawings and calculations documenting loads, materials, and code compliance, and responds to plan review comments. During construction, they review RFIs and submittals, inspect critical work such as rebar and anchors, approve field fixes, and help resolve unforeseen conditions.
What should I have ready before the first conversation?
Your goals for the project, any existing drawings or measurements, photos, a site survey, and a geotechnical report if one exists. For work on an existing building, measurements of what is already there — joist sizes and direction, spans, wall locations — make the first conversation far more productive.