Driveway Cleaning in Cairns

The black is not dirt

A Cairns driveway that has gone from pale grey to something close to charcoal has not collected dirt. It has grown a biological film, mostly algae and cyanobacteria, living in the top few millimetres of the slab where the pores hold moisture between storms. That is why hosing it does nothing, and why a broom and a bucket of sugar soap buys you about three weeks.

Concrete is one of the few surfaces around a house that genuinely wants high pressure. It is hard, it has no laps or sheet joins to force water behind, and the growth is deep enough in the surface that mechanical energy is the only thing that reaches it.

Why we use a surface cleaner, not a lance

The tell of a bad driveway clean is striping. Those zebra bands across a slab come from cleaning with a straight lance, where a narrow high energy fan has been walked across a wide surface and the overlaps have landed unevenly. It does not fade out. You see it every time the driveway dries.

We run a rotary surface cleaner instead: an enclosed head with jets spinning under a skirt at a fixed height, so every square metre gets the same energy for the same amount of time. Even coverage, no dwell in one spot, no bands. The lance only comes out for edges, expansion joints and the last hundred millimetres against a wall.

Not all concrete is the same

Sealed concrete changes the job completely. Pressure will lift a sealer unevenly and leave a cloudy, blotchy finish that looks worse than the growth did, so if a slab is sealed and the sealer is failing, the honest answer is that it needs stripping and resealing rather than washing.

Exposed aggregate needs distance. Get a rotary head too close and you scour the cement matrix out from between the stones, and once the stones are loose they stay loose. It cleans up beautifully at the right standoff and it takes longer, which is simply the trade.

Pavers lose their joint sand in the wash. Resanding is not cosmetic. Sand is what stops individual pavers rocking under a wheel and chipping at the edges, so it goes back in as part of the job.

Coloured and stencilled concrete gets tested on a hidden corner first. The colour is often only in a thin surface topping, and there is no getting it back.

Stains, and the ones not worth chasing

Oil needs a degreaser and time to work, not more pressure. Tannin staining from mango, poinciana and almond leaf drop through the wet season is a chemical problem too, and pressure alone just polishes it in. Rust from bore water irrigation takes a separate acid based treatment.

What is not worth chasing is a slab that is already spalling. If the surface is flaking away in sheets or the aggregate is popping out on its own, pressure will accelerate it and you will have paid to make a failing driveway fail faster.

Call 07 4028 4268 or send a photo through the quote form and we will tell you which of those you have.