Expert Vehicle
Welding in Cardiff.
Structural rust found during a mechanical or MOT inspection? We repair sills, floor pans, and chassis sections right here in our Rumney garage. High-quality, in-house welding with absolutely no subcontracting.
Rust underneath a car does not announce itself.
By the time corrosion is visible from street level, the structural damage below is often already significant. CF3 MOT & Service Centre in Rumney carries out full vehicle welding for cars, vans, and commercial vehicles across Cardiff, including structural MIG welding, MOT failure repairs, sill replacement, floor pan work, and chassis section repair. All welding is carried out in-house at our 6,000 sq ft Wentloog Road garage by our own experienced welders. Nothing is subcontracted.
Vehicle welding in Cardiff is needed in more situations than most drivers realise. A MOT tester's corrosion probe finds faults that look invisible from above. A pre-sale inspection turns up floor pan rust on a vehicle that otherwise looks clean. An older taxi hits a pothole on Newport Road and the sill collapses. We handle all of it from one workshop in Rumney, CF3.
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What Is Covered Under Vehicle Welding?
Vehicle welding is the cutting out and replacement of corroded, cracked, or missing steel sections on a vehicle body or chassis. It is different from filling or cosmetic patching. Proper welding cuts back to structurally sound metal, welds in new steel, primes bare metal, and seals the external face.
Welding Services We Carry Out at CF3, Rumney
- MOT weld repairs: sills, floor pans, subframe mounting points, chassis legs
- Structural sill replacement: outer and inner sill sections
- Floor pan repair and replacement
- Chassis leg and outrigger repair
- Inner wing repair and replacement
- Subframe mounting area repair
- Rust section removal and new steel welding
- Exhaust bracket and heat shield fabrication
- Bespoke panel fabrication for older and classic vehicles
All structural welding is carried out using MIG equipment on mild steel body sections. Every job is completed on-site by our own welders at our Rumney workshop.
We do not patch over corroded steel. We cut back to sound metal and weld new sections in properly.
Our approach is straightforward: cut back accurately, weld cleanly, finish properly.
Why Cars Fail MOTs on Welding in Cardiff
MOT testers use a corrosion probe and inspection lamp to assess the underside of every vehicle. Areas failing on structural grounds include:
Sills
The hollow box sections running along the bottom of the car body between the wheel arches. They rot from the inside out. Visually they can look intact at street level while being paper-thin underneath. Sill corrosion is one of the most common MOT failure reasons at Cardiff garages.
Floor pan
The pressed steel floor of the car body. Perforations in the floor pan fail on structural safety grounds regardless of which zone is affected.
Subframe mounting points
Where the front or rear subframe bolts to the bodyshell. Corrosion at these points directly affects suspension geometry and crash performance.
Chassis legs
The longitudinal front chassis rails on monocoque vehicles, particularly at engine mount attachment areas. Common on cars over 10 years old.
Cardiff's road conditions, persistent wet weather, and road salt use on the A48 Newport Road and M4 corridor accelerate underbody corrosion on vehicles driven in this area. Most drivers with cars over eight years old have some level of underbody corrosion worth checking.
Situations That Bring Cardiff Drivers to Us for Welding Work
A driver in Rumney receives an MOT failure notice citing both outer and inner sill corrosion. They can see some surface rust along the sill but had no idea the inner section was also gone. We put the car on the ramp, show them the extent of the failure, quote for both sections, and carry out the full replacement with underseal and primer included.
A Cardiff taxi operator with a Ford Transit on private hire plates brings in the van after it failed an MOT on floor pan perforation near the front footwells. The van has 190,000 miles and is otherwise mechanically sound. We cut out the affected sections and weld in new steel, allowing the retest to go through the same week.
An owner of a 2003 Rover 75 in Cyncoed wants the car kept on the road rather than scrapped. Two sill sections need complete replacement and the front chassis legs need patching at the engine mount area. We fabricate the sill sections to match the original profile and carry out the work over two days.
Trust Factors: Our Welding Standards and Experience
Structural Welding to MOT Standards
Structural welding on a vehicle is regulated under MOT standards. A poorly executed weld that does not meet structural integrity requirements will be picked up on the retest. Our welders have over 10 years of hands-on MIG welding experience on vehicle body and chassis work, working to the structural standards required for DVSA inspection retesting.
DVSA-Approved MOT Station
We are a DVSA-approved MOT testing station. Once welding repairs are completed, we retest the vehicle in our own MOT bay without you needing to travel to a separate garage. Every repair is inspected by the tester before the retest proceeds.
Rust Treatment Included
Rust treatment is standard after every repair. We apply weld-through primer to all bare metal and underseal to the external face as part of every weld job, not as an optional extra.
Vehicles We Weld
All structural welding is carried out in-house by our experienced mechanics in Cardiff, ensuring DVSA standards are met.
Book an InspectionCars
- Ford Focus
- Ford Fiesta
- Vauxhall Astra
- Vauxhall Corsa
- Peugeot 307
- Peugeot 206
- Toyota Corolla
- Volkswagen Golf
- Audi A4
- BMW 3 Series
- Rover 75
- Renault Scenic
- Honda Civic
- and most other passenger car makes from the 1980s to present
Vans and Commercial
- Ford Transit
- Mercedes Sprinter
- Vauxhall Movano
- Renault Master
- Volkswagen Transporter
Older and Classic Vehicles
We fabricate replacement sections where purchased panels are not available.
Finding Us From Across Cardiff and the CF3 Area
From Cardiff city centre via Newport Road, approximately 15 minutes.
From Newport via M4 Junction 30 and the A48 Newport Road, approximately 25 minutes.
- Free ramp inspection.
- Written quote before work starts.
- No charge for the assessment.
Evening appointments available Tuesday, Wednesday, Friday, and Saturday until 9pm.
Related Services
MOT Testing
Once welding repairs are complete, we retest the vehicle in our own DVSA-approved MOT bay on-site.
Accident Bodywork
Repair
Structural welding following collision damage is handled in-house alongside any panel repair and paint work.
Rust Repair and
Underbody Treatment
For vehicles with widespread corrosion, we carry out cavity wax injection into sealed internal box sections alongside the welding work.
Frequently Asked Questions
A vehicle with a formal MOT failure cannot legally be driven on public roads except to travel directly to a pre-booked garage appointment. Structural failures affect the safety of the vehicle in a collision. Call us on 07400 454839 to discuss collection if needed.
Cost depends on which sections are affected and the extent of the corrosion. Small sill patch repairs start from around £100 to £150. Full sill replacement or floor pan work costs more. We inspect the vehicle on the ramp and provide a written quote before any work begins. There is no charge for the assessment.
Small MOT weld repairs take half a day. Full sill replacement takes one to two days. More extensive floor pan or chassis work takes two to three days. We confirm turnaround at quote stage.
Yes. Once repairs are complete, we put the car straight through our DVSA-approved MOT bay for a retest. You do not need to book elsewhere or return on a different day.