The most expensive rust is the rust you cannot see. By the time corrosion shows on the outside of a sill or an arch, it has usually been working away inside the metal for years — and what started as a €100 prevention job has become a €1,000+ repair.
Where does hidden rust live?
- Inside box sections and sills — the hollow structural tubes of the body. Moisture condenses inside them and never dries out.
- Under seam sealer and trim — water creeps under lifting sealer and stays there.
- Behind plastic covers and liners — wheel-arch liners and underbody panels hide the metal behind them.
- Around suspension mounts and subframes — heavy, load-bearing parts that fail NCT inspections when corroded.
The financial side is blunt. Welding and fabricating a corroded sill or chassis section costs hundreds per section; a corroded subframe can be a four-figure part; and an NCT fail on structural corrosion takes the car off the road until it is fixed. Meanwhile a full preventive treatment — cavity wax inside the structure, coating underneath — costs a fraction of one repair.
Prevention only works before the damage is done. If your car is still sound, this is the moment. See the protection range or ask us what your car needs.