Concrete cleaning in Hamilton costs $3 per square metre plus GST. That rate covers paths, patios, courtyard slabs, garage floors, steps and commercial flatwork. What you actually pay comes down to how many square metres you have, what has stained or grown on them, and how easy the area is to reach.
This guide shows what the rate works out to at common sizes, how to measure your own area, and which stains come out and which ones do not.
What concrete cleaning costs in Hamilton
Sun SoftWash charges $3 per square metre for concrete cleaning, plus GST. The table below shows what that works out to at the sizes most Hamilton jobs fall into.
| Concrete area | Estimated cost (ex GST) |
|---|---|
| 20 m² | $60 |
| 40 m² | $120 |
| 60 m² | $180 |
| 80 m² | $240 |
| 100 m² | $300 |
| 150 m² | $450 |
Every figure is the area multiplied by $3, excluding GST. Paths, patios and garage slabs are usually smaller than a driveway, so a lot of jobs on this page come in at the lower end of that table.
The rate covers the labour, the equipment and the cleaning itself. Heavy staining, specialist stain treatments and awkward access are quoted on top of it, and the next sections explain what moves the number. Treat the figures above as guide prices: the firm price is confirmed once the surface has been assessed.
Work out your own area before you ask for a quote
Measuring is straightforward and takes a few minutes. For a rectangle, multiply the length by the width. A path 3 metres long and 1 metre wide is 3 square metres. Four paths that size come to 12 square metres, which is $36 at the standard rate.
Add up each separate slab the same way. A 5 by 4 metre patio is 20 square metres, so $60. A double garage floor at 6 by 6 metres is 36 square metres, so $108.
Hamilton properties often have several concrete areas rather than one big one: a front path, a side path down to the clothesline, a rear patio and a garage apron. Measure each of them and add the totals together, because they are cleaned and quoted as a single job.
If measuring by hand is awkward, phone measuring apps and the area tool in Google Maps are a reasonable cross-check on larger slabs. Slopes and irregular shapes are hard to trace accurately, so treat those tools as an estimate rather than a final figure.
Knowing your own square metres is worth the few minutes. It tells you straight away whether a quote is in the right ballpark, and it lets you compare two quotes on the same basis.
Which concrete surfaces this covers
Concrete cleaning covers anything made of concrete that is not a driveway. That includes paths and walkways, patios and courtyards, pool surrounds, garage and shed floors, steps and landings, vehicle crossovers, the faces of retaining and boundary walls, and commercial flatwork such as yards, forecourts and car parks.
Driveways sit alongside but have their own pricing guide, because vehicle areas pick up different problems: tyre marks, oil drops and the weight of constant traffic. If your job is a driveway, the driveway cleaning cost guide for Hamilton covers it in detail.
Concrete in more than one place is normal on Hamilton properties. Those areas are cleaned in one visit and priced together, which is why measuring all of them matters before you ask for a number.
Not everything hard and grey is concrete. Pavers, asphalt and timber decks all need their own method and are priced differently. If you are unsure what you have, a photo is usually enough for us to tell you.
What pushes a quote above the square-metre rate
The per-square-metre rate assumes a surface that needs a normal clean. A few things add time to a job, and time is what changes the price.
Heavy staining and growth. A path with light dirt washes down quickly. One that has been green for two winters needs to be pre-treated and left to dwell before anything is rinsed, which adds a step and a wait to the visit.
Moss and algae treatment. Where growth is established, a treatment applied at the root is what stops it returning within a season. Sun SoftWash publishes this as an add-on at $20 to $50, depending on how much of the surface is affected.
Oil and tyre marks. Oil stains are quoted at $10 to $30 each, and several on the same slab add up quickly.
Rust staining. Irrigation systems and fertiliser are the usual culprits. Published rates are $10 to $20 for light staining, $20 to $40 for moderate, and $40 and up for heavy or deep-set rust needing more than one treatment.
Access and slope. A flat patio beside the garage is quick to work around. A steep section, a slab behind a locked gate, or a path too narrow to run equipment along all slow the job down.
Condition. Concrete that has been left for several years takes longer than concrete that gets attention regularly. The dirt sits in the surface rather than on it.
Size works differently to what most people expect. One large slab is quicker to clean per square metre than the same total area split across five small, broken-up sections, because each separate area means setting up again.<!– FLAG: Moss treatment listed above as a $20–$50 add-on (main-domain published rate). The Hamilton driveway page states treatment is INCLUDED in the rate. Confirm which is correct before publishing. If included, delete the “Moss and algae treatment” paragraph and fold the point into “Heavy staining and growth”. –>
Surfaces that can’t just be blasted
Not all concrete responds the same way to water pressure, and the surface you have decides how much of it is safe to use.
Plain broom-finish concrete is the most forgiving. It is flat and even, with nothing sitting on top to strip off, so it handles normal controlled pressure without complaint.
Exposed aggregate is different. The finish is stones held in a cement matrix, and pressure that is too high strips that matrix away. Once the matrix is gone the stones sit loose on the surface and the patch never matches the rest of the slab. It needs lower pressure and more patience, not more force.
Coloured and stamped concrete carries its colour in the surface layer. Blast it hard and you etch that layer in the spots you worked hardest, which shows up as a pale, patchy area once it dries. Pressure is matched to the slab rather than run flat out.
Pavers are not concrete slabs at all. Pressure pushes the jointing sand out from between them, and once the joints open, weeds and ants move in and the pavers start to shift. Re-sanding or relaying is a separate job from cleaning.
Older slabs with hairline cracks are the last one to watch. Water driven into a crack can open it wider and lift material that was already loose. Existing damage is not a reason to skip cleaning, but it does change how the job is done.
Most of the exposed aggregate and coloured concrete in Hamilton sits in the newer subdivisions to the north and east of the city, where those finishes were popular on new builds. Older properties closer to the centre and through the south tend to have plainer, more porous slabs that hold moisture and stain faster.
Take a shaded exposed aggregate path that has gone uniformly grey with green settling into the low spots. Cleaned at controlled pressure, the stones come back to their own colour and the green lifts out of the texture. Blasted, the same path would come up patchy, with the matrix stripped from the high points and the loose stones visible from the street.
That is the whole principle. The cost of cleaning a surface properly is small next to the cost of repairing a surface cleaned the wrong way.
What stains Hamilton concrete, and what actually comes out
This is the question that decides whether cleaning is money well spent. Some marks lift off. Some need a treatment applied and left to work. A few will never clear completely, and you are better off knowing that before you book than after.
Moss and algae. The green film and black spotting that build up on shaded slabs, along fence lines and under trees. Treated at the root, it stays away. Blasted off the surface alone, it is back within a season because the growth underneath was never killed.
Lichen. Flat grey-green patches that look almost painted onto the concrete. Common on older slabs and on the tops of retaining walls. Lichen grips hard, and it responds to treatment and dwell time rather than more pressure.
Clay soil. Waikato clay sticks to wet concrete and dries into a stain that rinsing will not shift. It needs a cleaning solution and some agitation. Water alone just moves it around.
Rust from irrigation and fertiliser. Common on newer slabs where sprinklers reach concrete or metal edging. Fresh rust usually lifts with the right treatment. Rust that has been washing over the same spot for years can leave a faint mark behind.
Oil and tyre marks. Much of it comes out. Old oil that has soaked deep into the slab may only partly lift, whatever is used on it.
Efflorescence. The white, chalky bloom that shows up on some concrete. It is mineral salt carried to the surface by moisture moving through the slab. Cleaning removes what you can see, but if the moisture source is still there, it returns. That makes it as much a drainage problem as a cleaning one.
Leaf and tannin staining. Dark marks under trees and along fence lines, usually lifted once they have been treated.
Where a mark is unlikely to come out fully, we will tell you before the work starts rather than after.
How often Hamilton concrete needs cleaning
There is no fixed schedule, because concrete in shade behaves differently to concrete in full sun. Paths along the south side of a house, slabs under trees and anything that stays damp will grow moss again long before an open, sun-exposed patio does.
Staying ahead of it keeps the work simple. A surface that gets attention every year or two needs cleaning and a light treatment. One left for years needs a longer visit and more treatment to bring back.
On paths and steps there is also a safety point. Moss and algae on concrete are slippery when wet, which matters more on a slope or a step than in the middle of a flat patio.
When cleaning isn’t the right answer
Some concrete problems are not cleaning problems, and it is worth saying so.
Crumbling, spalling or badly cracked concrete needs repair or resurfacing. Cleaning will not restore it, and no amount of pressure will make a failing slab look right.
Sealing is a separate decision from cleaning. Some slabs benefit from it and some are better left alone, and either way it comes after the concrete is clean.
Concrete cleaning in Hamilton: quick answers
Is concrete cleaning charged per square metre or per job?
Per square metre, at $3 plus GST. The final figure is confirmed once the surface has been assessed.
Is GST included in the price?
No. The published rate is $3 per square metre plus GST.
Do you clean paths and patios, or only driveways?
Both. Driveways have their own cost guide, and everything else made of concrete is covered on this page.
Does pressure washing damage concrete?
Not when the pressure is matched to the surface. Damage happens when one setting is used on everything, especially on exposed aggregate, coloured concrete and pavers.
Will the moss come back?
Eventually, yes. Treating growth at the root slows it far more than blasting it off the surface, and shaded, damp areas regrow first.
Is it cheaper to hire a water blaster and do it myself?
For light dirt on plain concrete, sometimes. Where there is established growth or staining, the treatment and the correct pressure are what do the work. There is also the surface to consider: water at the wrong pressure can strip exposed aggregate or etch coloured concrete, and repaired concrete costs a lot more than the clean would have.
Ready for a firm number? Get a quote for concrete cleaning in Hamilton and we will confirm the price after looking at the surface.
