Excessive corrosion of the structure
How it can appear on an MOT certificate
- “Excessive corrosion of the vehicle structure”
- “Vehicle structure corroded”
- “Sill excessively corroded”
What it is
The MOT checks the load-bearing structure of the car (such as sills, floor and chassis members) for corrosion that weakens it.
Why it matters
Structural corrosion reduces the car's strength, including in a crash. It's a fail, and repairs can involve cutting out and welding in new metal, which can be costly.
What to check when viewing a car
Look along the sills (below the doors) and around the wheel arches for bubbling paint, holes or fresh underseal covering repairs. A garage inspection on a ramp is worthwhile on older cars.
Has the car you're looking at had this before?
Free: every MOT, every defect explained in plain English, mileage, tax and ULEZ.
What the MOT categories mean
- Dangerous
- A direct and immediate risk to road safety, or a serious impact on the environment. The car fails and shouldn't be driven until it's repaired.
- Major
- It may affect the car's safety, put other road users at risk or harm the environment. The car fails and should be repaired straight away.
- Minor
- No significant effect on safety or the environment. The car passes, but it should be repaired as soon as possible.
- Advisory
- Something to keep an eye on that could need repairing in future. The car passes.
Related: body and structure
- Corrosion near a suspension or brake mounting
- Body panel damaged with sharp edges
- Door won't open or close properly
Buying a used car?
General information about this type of MOT defect, not advice about a particular car. How serious it is depends on the car; have any car you're buying inspected by a qualified mechanic.