If you have applied for a building permit and the plan reviewer handed the application back asking for “engineered drawings” or “stamped calculations,” you are not being singled out. It is a routine request, and it usually means the project has reached a point where someone with a professional engineering license has to put their name on how the building will carry its loads.
This is a plain-language walk-through of what that request actually means, what ends up in the package, and how to get through it without the project sitting still.
What a building department is really asking for
A building permit application is a request to be allowed to build something. The plan reviewer’s job is to confirm that what you are proposing will stand up, hold what you plan to put on it, and handle the snow, wind and use it will see over its life.
For a lot of everyday work, the code has prescriptive tables that cover it. Standard joist spans, standard headers over standard openings. A contractor can point at the table and the reviewer can check it.
The moment a project steps outside those tables, the tables stop answering the question. That is when the reviewer asks for structural drawings and calculations prepared by a licensed engineer. It is not a judgment about your contractor’s work. It is that the code has run out of pre-approved answers and someone has to do the math for your specific building.
What goes in the drawing set
“Structural drawings” is shorthand for the sheets that show how the building holds itself up, as opposed to the sheets that show where the cabinets go. Depending on the project, that can include:
- A foundation plan — footing sizes and depths, wall thicknesses, reinforcing, and how the new work ties into anything existing.
- Framing plans — floor by floor, showing every beam, column, joist and header, with sizes and spacing called out.
- A roof framing plan — trusses or rafters, bearing points, and how the roof loads get down to the foundation.
- Sections and details — close-up drawings of the connections. Where a beam lands on a post, how a new header ties into old framing, how a column is anchored. Connections are where most of the real engineering lives.
- A general notes sheet — the design loads used, the material strengths assumed, and the standards the design was built on. This is the sheet the plan reviewer reads first.
The set does not have to be thick. It has to be complete enough that a reviewer can follow the loads from the roof to the soil, and complete enough that the crew in the field can build exactly what was designed.
What the calculations are doing
The drawings say what to build. The structural calculations are the written proof that those sizes work. In Wisconsin the loads that usually drive the answer are:
- Dead load — the permanent weight of the building itself. Framing, sheathing, roofing, flooring, drywall.
- Live load — the weight of what goes in and on it. People, furniture, inventory, equipment.
- Snow load — what accumulates on the roof, including drifting where a lower roof meets a taller wall. In this part of the state it is often the number that governs the roof design.
- Wind load — pressure pushing on the walls and lifting on the roof, and the uplift connections that resist it.
- Seismic and lateral — how the building resists being pushed sideways and stays square.
Each structural member gets checked against the combination of those loads that is hardest on it. The calculation shows the demand, the capacity, and the margin between them. When a plan reviewer questions a beam size, the calculation is the answer.
What the stamp means
A stamped drawing carries the seal and signature of a licensed professional engineer. In Wisconsin that is a state-issued license held by a person, not a company. The principal engineer at Curva Consultants holds Wisconsin PE License No. 47224.
The stamp is a statement that a licensed engineer prepared or directly supervised the design and takes professional responsibility for it. That is why a building department will accept a stamped drawing instead of a code table: the responsibility has a name attached to it.
It also means the engineer has to be satisfied before it gets sealed. If something in the design does not work, it gets resolved before the stamp goes on, not after.
Projects that usually need engineered drawings
Every municipality writes its own submittal requirements, so the only authoritative answer comes from the building department handling your permit. That said, these are the situations that commonly trigger the request:
- Taking out a wall. If it is carrying load, something has to carry it instead, and the new beam and its posts have to be sized and detailed.
- Additions. New structure tying into old structure, often on new footings next to existing ones. There is more on this in our guide to structural considerations for home additions and renovations.
- Large or unusual openings — wide sliders, garage door widenings, open-concept spans that no standard header table covers.
- Change of use. Turning a warehouse bay into a gym, or an office into a restaurant, changes the live load the floor has to carry even if nothing structural is being moved.
- Mezzanines and equipment platforms, and any machinery being hung from or set on existing framing.
- Commercial and multi-story work, where prescriptive tables generally do not apply at all.
- Repairs after damage, where the existing structure has to be evaluated before the repair can be designed.
If you are not sure which bucket your project falls in, a short conversation before you submit is usually enough to tell.
How to keep the permit moving
The delays we see most often are not engineering problems. They are missing information. Having these in hand at the start makes a real difference:
- Your architectural plans, even if they are preliminary. Dimensions and layout drive everything downstream.
- Measurements of what is already there for work on an existing building — joist sizes and direction, spans, wall locations, what the foundation looks like.
- The actual weight of anything unusual going in. Equipment cut sheets, tank capacities, rack loading. Guessing here almost always means redesigning later.
- Your municipality’s submittal checklist. They differ, and the checklist tells the engineer exactly what the reviewer expects to see.
- Any plan review comments you have already received. If a reviewer has written down what is missing, that is the most direct starting point.
What happens if the drawings are skipped
The permit does not get issued, which is the simplest version of the problem. The harder version is work that goes ahead without them: an inspector can require finished work to be opened back up so the structure underneath can be seen, and anything that does not check out has to be corrected before the project can move on.
Getting the structural work documented before the walls close up is a far smaller job than sorting it out afterward.
Working with Curva Consultants
Curva Consultants prepares structural drawings and calculations for permit submittal across northeast Wisconsin, working in wood, steel, concrete and masonry on residential, commercial, industrial and municipal projects. Offices are in Green Bay and Manitowoc, with regular work in De Pere, Ashwaubenon, downtown Green Bay and the surrounding communities.
If the project starts with a question about an existing building rather than a new design, that is a different first step — see what to expect from a structural engineer inspection. If damage is involved, forensic engineering and damage investigation is the starting point, and hiring your own structural engineer for an insurance claim covers how that works alongside a claim.
To get drawings and calculations started for a permit submittal, get in touch or call 866-455-0155. A full list of services is on the structural engineering services page.