That noise is the underside of your car meeting concrete. It is not usually because the driveway is steep. It is because the slope changes faster than the car can follow.
A long, evenly steep driveway is often fine. A gentle one with a sharp kink at the bottom will scrape every time.
Three places it happens
- At the street. Where the flat road meets the start of the driveway. The most common spot, and the one you hit at an angle.
- Mid-driveway. Where a steep section flattens off, often at a landing or a change in the block's slope.
- At the garage. Where the driveway meets the level slab. Scrapes here tend to be on the way in, at low speed.
In each case the car is bridging a break in the profile. The wheels follow the surface; the middle or the ends of the car do not.
Why your car and not your neighbour's
Three measurements decide it, and they vary enormously between vehicles:
- Ground clearance — how high the lowest point sits.
- Overhang — how far the body extends past the wheels. A long front overhang is the usual culprit.
- Approach and departure angles — how steep a break the car can enter and leave without contact.
A ute and a low sports coupe can meet the same transition with completely different results. This is why a driveway that satisfies every number on the drawing can still fail the only test the owner cares about.
What can be done
Options depend on where the contact is and how much room there is. In rough order of cost:
- Rubber ramps or kerb ramps at the contact point. Cheapest, least tidy, and often not permitted on the council-owned section near the street.
- Grinding the high point. Works where contact is light and localised. Limited by slab thickness and reinforcement.
- Re-forming a section — cutting out and re-pouring the transition to lengthen it. The usual real fix.
- Re-pouring the driveway. Occasionally the only option where the underlying profile is wrong.
If it is not built yet
This is the cheapest moment by a wide margin. Concrete gives you one chance — a poured driveway that grounds a car comes out and goes back in.
A driveway long section that states its levels, zone lengths, gradients and transition lengths can be checked against a specific vehicle before anyone pours anything. That is the point of designing the profile rather than setting it out on site.
More on the underlying principle in why rate of grade change matters, and on the limits themselves in how steep can a driveway be.
Disclaimer
General information, not advice. Whether a particular remedy suits a particular driveway depends on the slab, the site and the approval conditions. Work on the vehicle crossing between the kerb and your property boundary is usually subject to council requirements. Seek advice from your council or a qualified contractor before altering an existing driveway.
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