Road salt is what rusts cars in Ontario. Salty slush gets thrown up into the wheel wells, the rocker panels and the seams under the car, and it sits there all winter. Rust usually starts where you can't see it. It shows up later as bubbled paint or a soft spot in the floor.
Rust proofing and undercoating put a protective layer between that salt and the metal. Rust proofing is a thinner coating that works its way into seams and joints. Undercoating is a thicker layer on the underbody that also stands up to stones and grit.
We put the car on the lift first and look over the underbody. Any rust that's already there is noted and shown to you before we start, because a coating slows rust down but doesn't undo it. Then the coating goes on the areas salt reaches, and we keep it off the exhaust and brakes.
Why it matters
Salt keeps working
Ontario roads are salted from the first snow into spring. Every slushy drive leaves salt water on the underside, and it keeps eating at the metal long after you've parked.
Rust repair is a bigger bill
Rocker panels, floor pans and subframes that have rusted through need welding or new parts. Slowing rust down early costs less than cutting it out later.
The car lasts longer
In Ontario, body rust often retires a car before the engine wears out. A protected underbody helps you keep the car longer and makes it easier to sell.
Signs it's time
- You just bought a new or new-to-you car
- The underbody has never been treated
- Surface rust starting on the frame or underbody
- Bubbling paint on the rocker panels or wheel arches
- You park in a heated underground garage, where salt melts and sits
- You plan to keep the car for years
What's included
- Underbody inspection on the lift
- Existing rust noted and shown to you
- Loose dirt and debris cleared before coating
- Rust proofing into seams, joints and the frame
- Undercoating on the floor pan and wheel wells
- Rocker panels and wheel arches covered
- Exhaust and brakes kept clear of coating
How often
Once a year, before winter
Thinner rust proofing coatings wear off over a winter of salt and slush, so many drivers redo them every fall. Undercoating lasts longer, but chips and gaps should be checked and touched up.
