The short answer: A structural weld inspection confirms that each weld matches the drawings in size, length, type and location, and that it is free of cracks, incomplete fusion, excessive undercut and other rejectable defects. Every weld gets a visual inspection. Critical welds, such as complete-joint-penetration groove welds, may also be tested with ultrasonic or magnetic particle methods.
A structural weld inspection verifies that each weld is the right size, type, and length shown on the drawings and is free of defects that would weaken it. Every structural weld gets a visual inspection; critical welds — such as complete-joint-penetration welds in moment connections — may also get nondestructive testing like ultrasonic testing.
Who inspects structural welds?
On many commercial projects the building code requires special inspection of structural steel, performed by an independent inspection agency hired by the owner. Inspectors are typically Certified Welding Inspectors (CWIs) or hold equivalent qualifications. The engineer’s statement of special inspections lists exactly what must be inspected and how often.
What a visual inspection checks
- Size and length — fillet weld legs and groove weld reinforcement match the drawings.
- Location and type — the right weld is in the right place on every connection.
- Profile — no excessive convexity, concavity, or overlap.
- Surface defects — cracks, undercut beyond allowed limits, porosity, and incomplete fusion.
- Craters and arc strikes — filled craters and no stray arc strikes on members.
Nondestructive testing (NDT)
| Method | What it finds | Typical use |
|---|---|---|
| Ultrasonic (UT) | Internal flaws in groove welds | CJP welds in moment connections and splices |
| Magnetic particle (MT) | Surface and near-surface cracks | Fillet welds and critical connections |
| Dye penetrant (PT) | Surface-breaking defects | Non-magnetic materials or spot checks |
| Radiographic (RT) | Internal porosity and inclusions | Less common on building steel today |
How to avoid failed inspections
- Know the requirements early. Read the statement of special inspections before steel work starts.
- Keep access open. Inspectors need to reach welds before fireproofing, drywall, or decking covers them.
- Schedule inspections as you go. Inspecting connections in batches avoids tearing out finishes later.
- Work to the procedure. Proper joint prep, preheat, and technique prevent most rejectable defects.
What happens if a weld fails?
Rejected welds are marked, repaired — usually by removing the defective portion and re-welding — and re-inspected. That’s why we plan our structural welding around inspection from day one. If you’re facing a failed inspection or need weld repairs, get in touch.
How weld inspections fit the permit process in DFW cities
Owners are often surprised that two different people look at the steel on a commercial job. The city building inspector checks work against the approved permit. The special inspector, hired by the owner, checks the structural welds and bolts in detail and reports to the building official. Dallas, Fort Worth and Collin County cities such as Plano, Frisco and McKinney adopt the International Building Code with local amendments, so the Chapter 17 special inspection requirements apply in each. Forms, portals and scheduling rules still differ from city to city.
A typical sequence on a commercial steel job
- Permit review. The structural drawings and statement of special inspections are approved with the permit.
- Pre-construction meeting. Some cities and agencies hold one to confirm who inspects what.
- Inspections as work proceeds. The special inspector visits during and after welding and logs any nonconforming welds.
- Corrections. Repairs are made and re-inspected before the area is covered.
- Final report. The agency submits a final report stating whether discrepancies were corrected. The building official typically wants it before issuing a certificate of occupancy.
Plan around Texas summers
Long stretches of summer heat push a lot of steel work into early-morning hours. If the welders start at dawn and the inspector doesn’t know it, finished welds sit uninspected while other trades close in around them. Put inspection windows on the same schedule as the welding.
Requirements are set city by city, so check with your local building department. Our service area page lists the DFW cities we work in.
Key takeaways
- The engineer's statement of special inspections lists which welds get inspected and how often.
- Visual inspection covers every weld; ultrasonic testing is usually reserved for complete-joint-penetration groove welds.
- Schedule inspections before fireproofing, decking or drywall hides the connections.
- Rejected welds must be repaired and re-inspected, so first-time quality protects the schedule.
Frequently asked questions
Who pays for special inspections on a commercial project?
The building code puts the hiring of special inspectors on the owner, or on the engineer or architect acting as the owner's agent, so the owner usually pays the inspection agency directly. That keeps the inspector independent of the contractor whose work is being checked. Contracts often shift the cost of re-inspecting rejected work to the contractor responsible, so read that clause before the job starts.
Does a residential steel beam need a weld inspection?
Usually not a special inspection. One- and two-family homes are built under the International Residential Code, which generally doesn't require the special inspections commercial buildings get. The city's framing inspector still checks the work against the permit, and the engineer who sized the beam may want to see the installation or photos before issuing a letter. Requirements vary by city, so confirm with the permit office.
What is the difference between a CWI and a special inspector?
A Certified Welding Inspector is an individual credential issued by the American Welding Society after an exam and a review of experience. A special inspector is a role on a project: someone the building official accepts as qualified to perform the inspections listed in the statement of special inspections. Many special inspectors for structural welding are CWIs, but the credential and the role are separate things.
Planning steel work in Dallas–Fort Worth? Send us your drawings or photos for a free, written estimate.