Undersealing vs chassis repair: which do you need first?

Undersealing is prevention: a protective coating applied to sound steel. Chassis repair is correction: cutting out corroded steel and welding in new. If steel has already perforated, coating over it achieves nothing — the repair has to come first.

The wrong order costs money

Applying underseal over active corrosion seals moisture in against the metal. It looks fine for a season, then the same area fails, and the coating you paid for gets cut off during the eventual repair.

The right order

• Inspect on a ramp with the underside cleaned back
• Weld out any perforated or structurally thin steel
• Treat surface rust on areas still sound
• Seal seams, prime and paint
• Apply underbody protection across the whole underside

Do both in one visit

Once a vehicle is on the ramp and the underside has been cleaned back, most of the preparation for coating is already done. Combining the repair and the protection in one visit is significantly cheaper than two separate jobs.

See chassis repair Ireland for the welding side and our undersealing services for the protection side.