In Australia one tends to find spring the most suitable season for cleaning concrete paths. The humidity is down, there is more of an improving sun and the milder temperatures let the surface dry as it should. Then again, in places like Brisbane or further north where the summer brings its share of rain, you can do just as well in autumn or once the wet season has run its course.
Timing is important. Whether you are after mould and algae or have put down a stain treatment, pressure cleaned or otherwise, the concrete must be given time to dry. Make sure you have a dependable spell of fine weather on a bright day; it is the way to avoid any risk of a slippery regrowth and see better results. I am Isadora Fletcher and I have come to plan my outdoor cleaning by the forecast instead of optimism, having been taught the hard way that “it looks dry enough” is no scientific measure. For a vinegar paint removal trial, allow the concrete to dry fully first.
A Practical Approach Down Under
If you are in the east or south of the country, put a major clean on the calendar from early to mid-spring. That will take care of the moss, dirt and algae the cooler months have put down before you put the outdoors to heavy use.
Further north in the tropics and sub-tropics, wait for the easing of the rain and humidity at the close of the wet season. Do not be guided by the calendar so much as the local pattern; the Bureau of Meteorology’s climate data for Australia is worth a look before you pick a day.
Quick Guide to the Seasons
| Season or period | Best use | What to watch |
|---|---|---|
| Spring | For your main annual clean and to get at the mould | Cool nights or a shower you did not see coming |
| Autumn | To treat stains and do a pre-winter clean | Leaf litter and dew, which will slow the drying |
| End of the wet season | When the rainfall has abated | Overnight dampness and storms |
| Summer | Mild conditions for a spot clean | Water restrictions and the heat |
| Winter | Only if it is mild and dry | Long drying times and shade |
How often you clean is up to you. Some homes will want two goes over a shaded or damp path, but for most a thorough job once a year is plenty. It is more of a recommendation than a national statistic. Rainfall, the proximity of a garden bed or trees and how much foot traffic the path gets will dictate your schedule.
The Case for Spring
There is a good balance to be had in spring: longer days, faster drying than in winter and temperatures that are easier on the body when working. You are also in time to put an end to organic growth before it is a slip hazard.
An inspection of drainage or any loose edges and cracks is part of the process. And if the path is off the front door or where you entertain, the difference is as practical as it is cosmetic. One does not want to be lugging a tray of drinks over a green slab.
Making the Most of It
Sweep up the soil and leaves first. Put a concrete-safe product on any visible mould or moss and work in sections to keep the solution from drying out.
Afterward, give it a full day or more of dry weather to set in, particularly with exposed aggregate or a porous, shaded path. Do not put it on the books right before some rain is due; a shower will dilute the cleaner and make a patchy mess of things.
When Autumn is Preferable
You may prefer to leave it to autumn to get rid of leaf litter before the winter moisture comes in, or simply because the summer heat is too much. This is handy for paths by a verandah or under a deciduous tree.
A clear morning once the dew is off is ideal, but do not be late about it or the path will be wet after dark. The autumn sun can be deceiving in its lack of drying power on a south-facing path.
Take Advantage of the Wet Season Lull
Brisbane and the like offer a good opening at the tail end of the wet season. But do not go cleaning in the short respite between storms. You want a real window of dry weather, not three hours of blue sky and then a tropical deluge.
And when you have done the job, have a look at the downpipes and low spots where water has a habit of pooling. If you are not addressing the source of the water you are little better off than mopping under a tap that is leaking.
The Effect of Climate on Your Cleaning Schedule
There is no single cleaning calendar that applies to all of Australia. Given the diversity of the climate, from the tropical wet and dry of the north to the cooler, more inclement winters in some southern regions, when one should pressure clean concrete is a matter of humidity, shade, overnight temperatures and how much rain has fallen.
In northern Western Australia and the Top End it is best to plan for the dry season. The Red Centre and other inland locales will see a surface dry in short order but are prone to dust setting in again. On the coast you may find regular rinsing to be of more value than an annual clean owing to the salt, wind-blown sand and humidity.
Working With The Conditions
Pick a day the forecast has put in as bright with little wind and ample time for drying. You will want to avoid the extremes of heat for the sake of your workers who can dehydrate before the job is done, and because some cleaners have a habit of evaporating in full sun.
Under no circumstances should pressure cleaning be done in the face of a storm or strong winds, or where there is an official fire-risk restriction on the use of water and outdoor equipment. When conditions are severe, local advice should be heeded as bushfire closures and water rules differ from place to place.
Safe Concrete Cleaning
The approach to a concrete path is dictated by its condition, finish and the nature of any stains. Start off with the mildest method that will suffice and only put on more pressure or treatment if called for.
While a pressure washer will get at embedded dirt, overdo it and you risk etching the concrete, forcing water into cracks or bringing the aggregate to the fore. Make a test of an inconspicuous spot on an older or decorative path first.
A Checklist For Cleaning
- Ensure the weather will be dry for 24 hours or so; put away any toys, pots and outdoor furniture.
- Clear the edges and joints of weeds and sweep up loose dirt.
- Make sure spray and cleaner do not come into contact with electrical fittings, painted surfaces, pets or plants in the vicinity.
- Put on a biodegradable product made for concrete and adhere to what the label says.
- For light dirt a stiff brush will do, reserve the pressure washer for when the surface can take it.
- When rinsing, let the dirty water run to a proper drain and not into a neighbour’s yard or a stormwater inlet.
- Let the path be thoroughly dry and free of slip before allowing people or pets back on it.
Sodium hypochlorite can be useful against organic growth of a heavy kind, provided you handle it correctly. Do not mix with acids, vinegar or the like and use only what is labelled for the surface. A pair of gloves and eye protection along with enclosed footwear is sensible, nothing more.
Some Patience With Stains
An old stain is not going to be obliterated in one pass with the pressure cleaner. Oil in particular can be held under the visible surface by absorbent concrete and will call for a degreaser and perhaps several applications.
With paint, blasting it with a pressure washer is not always the safest course; you might do better to scrape and apply a remover after a spot test. A trial with vinegar does not excuse you from following the manufacturer or checking the finish of the concrete.
Cleaning As And When Required
Do not be bound by a rigid timetable. An open, sunny path with few treads will hold up, whereas one in the shade of trees is likely to put on algae after a few rains.
A good rule is to give it a light rinse at the first sign of dirt and a more thorough going over once it is discoloured or slippery. It is easier to clean before the organic layer becomes thick and hard to shift.
Exposure will tell you how often
| Path condition | Practical cleaning pattern | Reason |
|---|---|---|
| Sunny and unobstructed | Inspect monthly; deep clean about once a year | Faster drying and less organic growth |
| Shaded or next to the garden | Inspect fortnightly in wet weather; deep clean once or twice a year | More soil and humidity |
| Heavy foot traffic | Sweep weekly; spot-clean as needed | Dirt and grit accumulate faster |
| Exposed coastal spots | Rinse salt and sand regularly; deep clean as needed | Wind and salt build up on the surface |
These are guidelines. If a path is still damp days after a rain it will need to be looked at sooner than one that is dry in a matter of hours.
Consider Sealing
Sealing is not something you have to do on every path, but maintenance of the seal on concrete can go some way to prevent staining and water absorption down the track. It is worth doing on decorative or exposed aggregate work, newly put down surfaces and anywhere that gets a lot of oil, food or footfall.
A damp path is not to be sealed. The concrete should be in good order, clean and dry for the sealer of your choice, and you must put the product on as the instructions dictate. Moisture left in the concrete will lead to peeling, a lack of adhesion or cloudiness.
Check Before You Seal
Put some thought into whether the path requires protection in the first place. Is the sealer up to Australian outdoor conditions? Will the finish be slippery when it is wet? A glossy look can be deceptively tidy but it has a way of throwing a glare and changing how exposed aggregate concrete appears.
And do not think sealing absolves one of sweeping, checking the drainage or getting at the mould and algae. It is an aid to maintenance, not a force field from the rain, leaves or an overzealous neighbour with a garden hose.
Regional Timing Across Australia
There is no magic date for cleaning a concrete path in this country; it is a matter of observation. What is the right week in Perth might not be in Brisbane, and an inland town will have its own set of circumstances compared to a coastal suburb a couple of hours down the road.
Make plans for when the rain has let up and the path will dry without fail. Should you be hiring in equipment, get it early and factor in time to put hoses over gates and around parked cars; make sure you have water access.
Brisbane And New South Wales
In Brisbane one has to contend with humidity and heavy rain as well as shade. A clean in the late-wet or early-dry season is fine so long as the storms are done and there is sufficient sun to dry the path.
New South Wales sees a great deal of variation from the tablelands and coast to the inland. Salt and algae call for more regular tending on the coast. In the colder parts of the state, spring is preferable for a clean once the overnight cold has lifted.
Access And Practical Logistics
If doing it yourself, see that you have a clear run from the tap to the end of the job before you commence. Put the vehicles off the driveway, ensure the gates are unobstructed and there is a dry way to the front door. Give householders notice if the path is to be closed for the duration.
As for professional work, you will find no consistent price across Australia. The cost is dictated by the surface area, how bad the stains are, travel and so forth. Get a local quote in writing for the pressure cleaning, wastewater disposal, products and any sealing you may want.
Common Cleaning Errors To Steer Clear Of
Rushing the prep is where most trouble comes from, as is the notion that more pressure equates to a better clean. Concrete is hardy but porous and an etched stripe is far more unsightly than the dirt was.
Then there is the issue of drying time. Shaded joints and edges can still be damp below what looks like a dry top; make a point of checking them. Other mistakes include:
- Getting too close with the pressure washer and leaving lines.
- Putting off a clean until just before a shower and letting the muck settle back.
- Not dealing with a leaking tap or gutter that is the source of the problem.
- Combining chemicals, in particular acids or vinegar with anything chlorine-based.
- Sealing on concrete that is not properly clean and dry.
- Failing to put plants, pets and electricals out of harm’s way.
A novice can cope with a small, sound path and some mild soiling with care and the right gear. But leave it to the pros if there is extensive oil, mould or decorative concrete of a fragile nature, or old coatings you are not sure of.
Frequently Asked Questions
What Is The Best Time Of Year To Clean Concrete Paths In Australia?
Generally speaking, spring is the answer. The days are longer, the weather is mild and you can get the winter grime off before it gets hot or wet. Up north, you may find the tail end of the wet season more to your liking.
Should Concrete Paths Be Cleaned Before Or After The Wet Season?
Do it beforehand to put an end to organic growth and dirt. Do it after if the rains have put down a layer of mud or fresh mould. Most homes would do well with a light pre-wet-season clean and then something more thorough later on.
How Often Should Concrete Paths Be Pressure Cleaned?
Once a year is typical for many, though twice is called for on a high-traffic or shaded path. Do not put it to the calendar, if the surface is looking contaminated or is slippery, clean it.
What Is The Best Cleaner For Concrete Paths?
Water and a biodegradable cleaner made for concrete will handle ordinary dirt. For organic growth you might need a sodium hypochlorite treatment of sorts, but read the label and do not mix your chemicals.
Can You Pressure Wash A Concrete Path?
You can, if the concrete is in sound condition and you have the technique. Make a test of an inconspicuous spot and do not hold the spray on a crack or joint.
How Do You Remove Mould And Algae From Concrete?
Brush off the loose bits and put on a concrete cleaner, let it dwell and then scrub and rinse. Afterwards see to the drainage and sunlight; in a damp spot, a clean is not enough to keep regrowth at bay.
When Should Concrete Paths Be Sealed?
Only after a clean and when the concrete is thoroughly dry. Pick an outdoor sealer that will not make the path treacherous in the wet.
Plan Around The Weather
The season that affords you reliable drying is the one to use. Spring is the default, autumn is good before winter sets in and in humid climes like Brisbane the post-wet-season is ideal.
Be gentle, fix any drainage issues and let the path dry. Done right, it will be safer underfoot and in better shape to stand up to the next round of classic Australian weather.
