Structural steel projects rarely go exactly to plan—design refinements, site conditions, or client needs shift mid-fabrication. Knowing how to manage changes without derailing your timeline or budget is the difference between a successful project and a costly headache. This guide walks you through the realistic steps to handle modifications with your fabricator.
Why Changes Happen (And Why They're Common)
Change orders in structural steel aren't unusual. Your architect may spot a conflict with MEP routing, a building inspector might flag a detail, or your budget constraints force a design tweak. The key is treating modifications as a structured process, not a casual conversation over email.
Establish a Change Order Process Upfront
Before fabrication starts, confirm your fabricator has a formal change order system. This should include:
- A written template documenting the change, reason, impact on schedule, and cost adjustment
- A clear approval chain (who signs off: you, the general contractor, the structural engineer)
- A timeline for submitting changes (ideally at least 5–7 business days before affected fabrication work begins)
- A baseline price—know what your contract originally specified so cost deltas are transparent
Reputable fabricators like those searchable on Mercoly have documented processes and won't proceed on verbal approvals alone.
Assess the Real Cost and Schedule Impact
A "simple" change rarely is. When you request a modification—say, adding a reinforcing plate or shifting a connection detail—your fabricator needs to evaluate:
Design and Engineering Your fabricator's engineer must redraw the detail, check it against the building code, and confirm it doesn't conflict with adjacent members. This typically costs $200–$600 per detail, depending on complexity.
Material Lead Time If the change requires different steel grades, sizes, or additional tonnage, supplier delays can push your delivery back 2–4 weeks. Some materials (heavy plates, special shapes) have 8–12 week lead times.
Fabrication Rework If steel is already cut or partially welded, scrapping and redoing that work is expensive. A change mid-production can add 15–30% to labor costs for that piece.
CNC and Setup Time Reprogramming cutting, drilling, or punching equipment takes time. Simple changes might add 4–8 hours; complex ones can add days.
Your fabricator should itemize these costs in writing before you approve. A typical small change (a few added holes, a minor dimension shift) might cost $1,500–$4,000 and slip the schedule by 3–7 days. Larger changes can easily exceed $10,000.
Document Everything in Writing
Never rely on phone calls or texts. For every change:
- Send a written request describing the modification clearly (include sketches if possible)
- Get a formal quote from your fabricator—not a rough estimate
- Obtain structural engineer sign-off that the change meets code
- Have the general contractor approve if they're coordinating trades
- Sign and return the change order before work resumes
This paper trail protects you if disputes arise later about scope or cost.
Know Your Contract Terms
Review your original fabrication contract for clauses about:
- Change order markup: Some fabricators add 15–25% overhead to change costs beyond material and labor
- Timing restrictions: Changes requested after a certain fabrication stage may incur steep penalties
- Approval authority: Who has the power to sign off? (Usually the general contractor or architect, not just you)
- Force account work: Can your fabricator charge time-and-materials if the scope becomes undefined?
If your contract is vague here, clarify it now—before you need a change.
Plan for Cumulative Delays
One change rarely stays one change. If your structural system shifts, related connections may need revision. A 2-week delay in steel delivery can compress your erection schedule. Build a buffer—work with your fabricator to understand the cumulative risk.
Frequently Asked Questions
Q: How far into fabrication can I safely request changes? Changes are easiest (and cheapest) before steel is cut; moderately complex if requested during cutting but before welding; and very expensive if parts are already assembled or shipped. Ask your fabricator for the "change cutoff date" during initial planning.
Q: Will my fabricator charge me for changes they caused? No—if your fabricator made an error in interpreting the drawings, they should correct it at no cost. Changes driven by your requests, site conditions, or design evolution are always billable.
Q: What if the change order cost is way higher than expected? You have three options: accept the cost, redesign to avoid the change, or negotiate with your fabricator on phasing or alternatives. Get the quote in writing before deciding.
Start your search for a fabricator with a documented change-order process by comparing local providers on Mercoly.