UKCA Marking and BS EN 1090 EXC2: Why It Matters for Your Structural Steel

What UKCA marking and BS EN 1090 EXC2 actually mean, why buyers, architects and contractors should insist on them, and the real risks of non-compliant structural steel.

Structural steel holds up everything else in a building. A beam over a knock-through, the frame of an extension or the columns under a mezzanine all have to carry their load safely for decades. So when you buy fabricated structural steelwork, you need more than a good price. You need proof that it was made properly.

That proof is **UKCA marking to BS EN 1090**. Here is what it means, why you should insist on it, and what can go wrong if you don't.

## What is BS EN 1090?

BS EN 1090 is the harmonised standard for fabricating structural steel and aluminium components. It has several parts. The two that matter most here are:

- **BS EN 1090-1** covers how fabricators show their components conform. It requires a certified **Factory Production Control (FPC)** system, audited by an approved body.

- **BS EN 1090-2** sets the technical rules for executing steel structures: materials, cutting, welding, bolting, tolerances, inspection and testing.

In short, BS EN 1090 makes sure a fabricator has documented, controlled and audited processes, not just skilled welders.

# What does EXC2 mean?

BS EN 1090 sorts structures into four **Execution Classes**, EXC1 to EXC4. The higher the class, the stricter the requirements for welding quality, inspection, traceability and staff qualifications.

- **EXC1**: simple, low-consequence structures such as some agricultural buildings and basic stairs.

- **EXC2**: the most common class for buildings in the UK. It covers most residential, commercial and industrial steelwork, including beams, columns, portal frames, mezzanines and extensions.

- **EXC3 and EXC4**: high-consequence structures such as large stadia, bridges and major public buildings.

The structural engineer sets the execution class for the job. Because most UK building work is specified at EXC2, a fabricator certified to **EXC2** can legally supply the vast majority of projects. A fabricator certified only to EXC1 cannot.

EXC2 certification also means the fabricator has:

- A qualified **Responsible Welding Coordinator (RWC)** overseeing welding work

- Qualified welding procedures (WPQRs) and certified welders

- Full **material traceability**, from mill certificate to finished piece

- Documented inspection and testing

- Regular external audits of the whole system

## What is UKCA marking?

UKCA (UK Conformity Assessed) is the product marking used in Great Britain. It replaced CE marking after Brexit. Under the UK Construction Products Regulation, fabricated structural steel components covered by BS EN 1090-1 **must** be UKCA marked (or, where still accepted, CE marked) before they are placed on the market.

A UKCA mark on structural steel means the fabricator holds a certified FPC system to BS EN 1090 and supplies a **Declaration of Performance (DoP)** stating the component's key characteristics. It is not a badge a fabricator can choose to use. It is a legal requirement for the product.

## Why buyers, architects and contractors should insist on it

### 1. It's the law

Supplying structural steel components without the required marking breaches construction products regulations. If you are the contractor or client, non-compliant steel in your building becomes your problem too.

### 2. Building control will ask

Building control officers and approved inspectors increasingly ask for evidence of compliance, such as the DoP, the UKCA marking and the execution class. If the paperwork isn't there, sign-off can be delayed or refused. That can mean costly remedial work, or even removing and replacing steel that's already installed.

### 3. Insurance, warranties and resale

Structural warranty providers, insurers and lenders expect structural elements to be compliant. Non-compliant steel can affect cover, cause problems with completion certificates and come up during conveyancing when the property is sold.

### 4. Traceability gives accountability

With EXC2 you know exactly which grade of steel was used, who welded it, to which procedure, and how it was inspected. If a question ever comes up, there's a full paper trail.

### 5. Professional duty

Architects, engineers and principal contractors have a duty of care. Since the Building Safety Act, the industry has been under much closer scrutiny over product compliance and the "golden thread" of information. Specifying and checking for UKCA-marked EXC2 steel protects your clients and your professional reputation.

## The risks of non-compliant steel

Cheap, uncertified steelwork can look identical to compliant steel once it's painted and installed. The difference is what you can't see:

- **Poor welds**: lack of fusion, porosity or undersized welds that may fail under load

- **Wrong materials**: unverified steel grades with lower strength than the design assumes

- **Dimensional errors**: out-of-tolerance members that don't fit, causing problems on site or stressing connections

- **No paper trail**: no mill certificates, no weld records, no inspection reports, and nothing to show building control

- **Liability**: if something fails, every party in the chain may face claims, and having no compliance documentation makes them very hard to defend

- **Delays and rework**: failed inspections, stopped work and replacing steel cost far more than doing it right first time

The few pounds saved on uncertified steel can quickly become thousands spent on putting it right, and in the worst case a serious safety risk.

## What to ask your fabricator

Before you place an order, ask:

1. Are you **certified to BS EN 1090-1**, and to which **execution class**?

2. Can you provide your **FPC certificate** and who issued it?

3. Will the steel be **UKCA marked**, and will you supply a **Declaration of Performance**?

4. Who is your **Responsible Welding Coordinator**?

5. Can you provide **mill certificates and traceability** for the materials?

A reputable fabricator will answer all of these straight away and be happy to show the documents.

## How JAS Welding Services can help

At **JAS Welding Services Ltd** in Norwich, all of our structural steelwork is fabricated under our **BS EN 1090 EXC2 Factory Production Control** system and **UKCA marked**. You get documented, traceable steelwork that satisfies building control.

With more than 15 years' experience, we handle the whole job:

- Steel beams, RSJs, columns and portal frames

- Steel frames for extensions, loft conversions and knock-throughs

- Mezzanine floors, platforms and support steelwork

- Commercial, agricultural and industrial structures

- Structural calculations arranged through our engineering partners

- Fabrication in our Norwich workshop and installation by our own team

We also provide **RWC (Responsible Welding Coordinator) services** to other fabricators and contractors who need qualified support with their own compliance.

**Need compliant structural steel for your next project?** Send us your plans or engineer's drawings for a free, no-obligation quote.