Prefabricated Structural Steelwork
Prefabrication-first - every joint pre-welded in the workshop means one fewer hot-works permit on site, one fewer fire watch, and less disruption to adjacent trades.
What we deliver.
We fabricate structural steelwork for pre-welded assembly and delivery ready to erect - primary frames, secondary steel, connection assemblies, mezzanine sections, stair stringers, and bolted-connection sub-assemblies all shipped from the Rotherham workshop. Every joint we can prefabricate is one fewer hot-works permit on site, one fewer fire watch, one fewer day adjacent trades can't work, and one fewer joint subject to site conditions. Dimensional accuracy is validated against the Tekla model before dispatch; bolt-up and adjustment windows are designed into the connection details. Where site welding is required, it is carried out by coded welders to BS EN ISO 9606 with full hot-work permits and fire watches in place.
What we make.
Every project follows the same certified workflow - so you get the same outcome whether we're making one beam or a thousand.
Pre-welded assemblies shipped ready to erect
Connection assemblies, mezzanine sections, stair stringers, moment frames, truss panels, and any piece we can transport in one go arrive at site pre-welded. Bolt-up connections are detailed with adjustment windows so the erector can align cleanly; site-weld joints are limited to locations such as tight-access splices and oversized-piece joints.
Programme and cost advantage
Prefabrication reduces site hot-works hours, which reduces fire-watch provision, adjacent-trade idle time, and overall programme length. On commercial fit-outs, the difference between a pre-welded erection and an on-site welding programme can be substantial. The cost benefit shows in the site overhead, not only in the fabrication quote.
Tekla dimensional validation
Every prefabricated assembly is dimensionally validated against the Tekla model before dispatch. A prefabricated piece with a dimensional error cannot be adjusted on site in the same way a site-welded piece can, so the check happens in the workshop. Measurement records ship with the delivery; any variance from model is flagged before the lift is booked.
Site welding discipline when required
Where site welding is required - tight-access splices, oversized-piece joints, or retrofit connections into existing structural - it is carried out by coded welders to BS EN ISO 9606, travelling with the erection crew. Full RAMS, hot-work permits, fire watches, and NDT where specified. Site welding is not outsourced.
Craftsmanship. Accountability. No shortcuts.
No subcontracted welders. No outsourced site crews. Every project from 3D model to final torque-check is handled by a certified UIS team from our Rotherham facility.
Tour our workshop
Project & sample images.
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Four reasons we stay on your shortlist.
The same four reasons come up whether you're a tier-one contractor, architect or self-builder.
About UIS-
01
Accreditations & compliance
BS EN 1090 Execution Class 2. CHAS Elite, Alcumus SafeContractor, ISO 9001. Every project ships with a full QA pack.
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02
Experience & capabilities
Thirty years in business. Drawing board to torque-check happens in-house - no split accountability.
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03
People & values
CSCS operatives. Coded welders. Chartered draughtsmen. A family firm that treats your project like their own.
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04
Innovation & sustainability
Tekla 3D modelling. Automated welding cells. GRP composite solutions where steel isn't the right answer.
"I've worked with UIS for several years on some high profile and very complex projects. Their attitude and work ethic are second to none - providing high quality services and products which are delivered safely and on time every time. Overall they are a pleasure to do business with and wouldn't hesitate recommending UIS for any steelwork or metalwork packages."
Questions clients ask us.
On most commercial packages, 80-95% of welding by weld-metre can be prefabricated. Exceptions include oversized pieces that cannot transport in one go and require a site splice, retrofit connections into existing primary structural, and connection types where the detail requires site fit-up. We review the package at design stage and flag which joints have to be site-welded, so the hot-works allowance is realistic in the quote.
Fire-watch hours, hot-works permit administration, adjacent-trade idle time, weather-delay risk, and fume-extraction provision. Prefabrication typically shortens the critical-path erection window, which means downstream trades can start earlier and the overall programme is reduced.
Not if we are involved at design stage. Connection geometry is designed for prefabrication from the start - bolt-up adjustment windows, transport-friendly piece sizes, and an erection sequence that accounts for site access. Late engagement on an already-designed package limits the prefabrication ratio; early engagement maximises it without compromising the architectural design.
Rare. Tekla dimensional validation before dispatch catches most dimensional variance. Where a fit issue does arise - usually from an existing-structure dimension that differed from the survey - our coded welders on the erection crew can site-modify to procedure. The fabrication team is contactable during erection, so unusual fit-up decisions are reviewed before they are acted on.
Recent project deep-dives.
Reclaimed Structural Steelwork Project London November 2025
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Stainless Steel Powder Coated Handrails with LED Lighting December 2025
Another successful project completed and handed over! ✅ 😘 Our client requested ourselves to supply and install the stainless steel p...
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Large Steel Construction and Erection Project London December 2025
We are proud to share that our team has successfully completed and installed another high-quality steelwork package right in the heart of Lo...
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