Most build contracts give the driveway a line or two, and it's rarely where attention sits when plans are signed off. By the time it is, the slab is poured and the garage level is fixed.
Four questions cover most of the risk. What is your garage slab level, and what boundary level was it worked back from? Who arranges the vehicle crossing, and to which council drawing? Is the driveway designed, or set out on site? And who pays if it comes out?
Ask before the slab level is set
Your garage floor is the top of your driveway. Once it's on the contract drawings, moving it means moving the house.
Asked during design, these questions change a number on a drawing. Four documents answer most of what follows:
- The site plan, showing the garage finished floor level and the boundary level.
- The contour survey those levels came off.
- The council standard drawing for the vehicle crossing at that address.
- A driveway long section, if one exists.
1. What is the garage slab level, and what boundary level was it set from?
The slab level is driven by the house, the drainage and the flood level, not by the driveway. Whatever height that leaves between garage and street has to be lost over the driveway, and a short frontage may not have the room.
Divide that height by the distance for the average grade. If it already sits near the Queensland maximum of 1 in 5, your driveway is tight the whole way before anyone has designed anything. Boundary RL to garage RL is where design starts.
What a good answer sounds like
Two figures and their source. Boundary level 12.40 off the survey, garage finished floor 14.10, eighteen metres between them. Then whether that figure is finished floor or top of slab, which differ by the slab thickness.
2. Who is arranging the vehicle crossing, and to which standard drawing?
The concrete between the kerb and your boundary usually belongs to the council. It's built to the council's standard drawing, not your building approval, and carries its own permit and gradient requirement, often flatter than what's allowed behind the boundary.
On a tight block it's often the binding constraint. Whether your builder prices it or leaves it to you varies between contracts, so get it stated. Crossover or driveway covers the split.
What a good answer sounds like
A name against the permit application, the drawing identified by number, and whether it's in the price. If nobody can name the drawing, nobody has read it.
3. Is the driveway being designed, or set out on site?
On a flat block, setting the driveway out on site works fine. On a steep one, the fall available, the length of the steep run and the easing at each end have to work together.
A long section settles it before anyone pours, giving the level at each end, the grade and length of every zone, and the transitions. Reading a driveway long section shows one.
What a good answer sounds like
Either a long section exists, or the builder can say who produces it and when. On a steep site, "we'll sort it out when we get there" means the profile is decided by whoever holds the screed.
4. If the driveway has to come out, who pays?
The uncomfortable question, and the cheapest to ask. A driveway that grounds cars is usually found after handover, by a vehicle rather than an inspection, which makes it a dispute rather than a defect.
Where that cost falls depends on your contract and on who set the levels, and it varies between builders. Ask which clause covers a driveway that doesn't comply with the approval conditions, and get that in writing. What rectification costs is worth reading first.
What a good answer sounds like
A specific clause, and a straight answer on who sets the garage level and who checks the driveway against it. Silence isn't bad faith, but the question is easier to close before you sign.
Ask early, and keep the answers
None of this asks you to read a standard, just four answers in writing while the levels can still move.
After the pour, it's a negotiation.
Disclaimer
General information, not advice. This article does not describe the terms of any particular building contract, and how responsibility for a non-complying driveway falls varies between builders, contracts and jurisdictions. The gradient mentioned here summarises QDC NMP 1.1 as published rather than reproducing it, and vehicle crossing requirements are set by each local government in its own standard drawing. Confirm the requirements for your property with the relevant council or a qualified certifier, and the contract position with your own adviser, before relying on anything here.
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