Floor Levelling near you

For a concrete floor, Queensland's guide says new floors are defective within twelve months from completion if they differ in level by more than 10 mm in any room or area, or more than 12 mm in any 3 m length, where that deviation adversely affects safe use or reasonable amenity, and that the overall deviation of floor level across the entire building footprint must not exceed 20 mm.

For a timber floor the number tightens. The same guide says floor levels within a room or area are defective within twelve months if they differ by more than 10 mm in any room or area, or more than 4 mm in any 2 m length, again where that affects safe use or reasonable amenity. For tiling it is tighter still and stated as flatness rather than level: tiling is defective within twelve months if, measured with a straight edge, the finished surface is not flat or true within plus or minus 4 mm in 2 m from the required plane, with lippage between adjacent tiles defective above 2 mm, above 1.5 mm for tiles ground flat such as polished tiles, and above 1 mm for joint widths of 3 mm or less.

Read those three together and the logic is obvious: a slab that is perfectly acceptable as a slab may not be acceptable as a base for tiles. That is why the guide also states, separately, that the finish to a concrete slab is defective if it is not suitable for the documented applied finishes, naming tiles, polished concrete, carpet and sheet flooring, including set-downs where required. Levelling work exists to close the gap between what the builder was allowed to deliver and what the floor covering needs.

Survey first. A grid of levels taken across the room, recorded, gives you the shape of the problem and the volume of material needed. Without it, a levelling quote is a guess, and levelling compound is priced by the bag. Ask to see the survey, because it also tells you whether the problem is one hollow or the whole plane.

Then preparation, which is where most levelling failures are made. The slab has to be clean, sound and free of adhesive, paint, curing compound and laitance, and it has to be primed with the primer the compound manufacturer specifies. A self-levelling compound poured onto an unprimed or dusty slab will debond, and the failure shows up as hollow-sounding areas and eventually as cracking under the covering.

Then the pour or the screed, and then the wait. Cementitious levelling products have a minimum and a maximum thickness and a drying time before a covering can go down, and the drying time is longer than the curing time. In a humid Australian summer, or in a closed-up house, it can be considerably longer than the bag says. A floor covering laid over a compound that has not dried will trap that moisture, and the covering carries the blame for a problem that belongs to the timetable.

Not every unlevel floor should be levelled. If a slab is out by a large amount across a long room, the volume of compound needed becomes expensive and heavy, and the resulting height change can cascade through the doors, the skirting, the stair at the bottom step and the kitchen. It is sometimes better to choose a covering that tolerates the floor: a floating plank floor with a good underlay handles a gentle fall far more gracefully than a large-format tile does.

Tile size is the quiet variable. A large-format tile is a rigid plane, so it cannot follow a hollow, and the deviation shows as lippage at the joints — which Queensland's guide treats as defective above 2 mm, and above 1 mm where the joint width is 3 mm or less. Smaller tiles, or a slightly wider joint, absorb more of the base's imperfection. Changing the tile can be cheaper than changing the floor.

And if the floor is moving rather than merely uneven, levelling is the wrong job entirely. A slab that has cracked and stepped, or a timber floor that bounces, is telling you about the structure or the soil beneath it. Levelling over that buries the evidence and the new surface will crack again. That is a concrete levelling or foundation question, and it needs diagnosis before finishing.

The single most useful thing you can do is name the tolerance in the quote, and name the covering it is for. Something as simple as requiring the finished base to be flat within plus or minus 4 mm in 2 m for a tiled floor, or within 4 mm in any 2 m length for a timber floor, turns a vague expectation into something both sides can measure with a straight edge. Queensland's guide gives you the numbers; using them is free.

Also settle who owns the levelling. On many jobs the flooring installer discovers the base is out on the day they arrive, and the levelling becomes a variation at their hourly rate. Having the base surveyed and levelled as its own scope, before the covering is ordered, removes that surprise and usually costs less.

The Australian Consumer Law guarantees apply to the work: acceptable care and skill, fitness for any stated purpose, and supply within a reasonable time. Keep the level survey, the product data sheet for the compound and the drying times, since those three documents settle most later arguments. LokalMatch is the place to get the survey-based quotes side by side and see which contractor measured and which one estimated.