Retaining walls do a lot of the heavy lifting on a property — holding back soil, managing water runoff, keeping garden beds in place. But because they’re functional rather than front-of-mind, they tend to get ignored when it comes to cleaning.
The problem is that retaining walls sit close to soil, collect moisture, and often sit in shaded areas. That’s the perfect recipe for heavy mould, lichen, and algae build-up — and left long enough, that growth can actually start working into the surface of the material.
A pressure clean strips it all back, restores the look of the wall, and in some cases gives you a better view of whether there are any maintenance issues worth keeping an eye on.
Retaining walls need a bit more thought than a flat driveway or patio. A few things make them different:
They’re vertical, which means water and detergent runs down fast — pre-treatment needs time to work before rinsing. They’re often right up against garden beds, so we need to be careful with runoff and any products we use near plants. And depending on the material, some walls need careful pressure control to avoid dislodging mortar, joints, or surface texture.
We assess every wall before we start and adjust the method accordingly. The goal is a clean wall, not a damaged one.
Retaining walls across the Central Coast are built from a wide range of materials. We clean all of them:
Not sure what your wall is built from? Send a photo and we’ll confirm the right approach before we book anything in.
Mould and lichen are the two most common issues we see on retaining walls across the Central Coast. Both thrive in the shaded, damp conditions that most retaining walls sit in — and both can be stubborn if they’ve had time to establish properly.
Light mould and algae usually comes off with pressure alone. Thicker lichen growth — the crusty, patchy kind that almost looks like it’s part of the surface — needs a pre-treatment with a biodegradable biocide or detergent to break it down before rinsing. We carry both and apply whichever is appropriate for what we’re dealing with.
After cleaning, lichen and mould tends to come back slower than it went on the first time, especially if the wall gets a bit more sun exposure once the growth is removed.
Get in touch for a free quote. We’ll ask about the length and height of the wall, the material, and the general condition. Longer walls or walls with very heavy staining take more time, so having a rough idea of the size helps us give you an accurate number.
On the day we inspect the wall up close before starting — checking for any loose material, cracks, or sections that need a lighter touch. We pre-treat where needed, pressure wash at the right PSI, and rinse thoroughly. We check the result from a few metres back before packing up to make sure nothing’s been missed.
We service retaining walls throughout the Central Coast including:
Terrigal, Avoca Beach, Wamberal, MacMasters Beach, Gosford, Point Clare, Erina, Springfield, Kincumber, Saratoga, Ettalong Beach, Umina Beach, Woy Woy, Tuggerah, Wyong, Hamlyn Terrace, Lake Haven, Toukley, The Entrance, Bateau Bay, Shelly Beach, and surrounding areas.
Not on the list? Get in touch anyway — we cover more of the Coast than most.
Pricing for retaining wall cleans depends on the length and height of the wall, the material, and how heavily soiled it is. Most residential jobs come in between $120 and $350. Long boundary walls or walls with dense lichen growth sit toward the higher end.
If you’re getting other areas done at the same time — driveway, patio, or pathways — bundling everything into one visit is the most cost-effective way to go. We’ll put together a combined quote.
We always price upfront. No changes on the day.
It can if the wrong pressure is used — particularly on older brick walls with ageing mortar, or sandstone and limestone that can be etched by high pressure or acidic cleaners. We assess the wall before starting and adjust accordingly. We've cleaned a lot of retaining walls without causing damage.
Yes, with the right approach. Timber needs a soft wash — lower pressure and appropriate detergent — rather than the full force used on concrete. We avoid forcing water into existing splits or end grain where possible. It cleans up well without accelerating any weathering.
Sometimes, yes — and that's actually useful to know. Cleaning removes the layer of growth and staining that can mask surface cracks, efflorescence, or areas where mortar is starting to fail. If we spot anything worth flagging while we're working, we'll point it out.
A standard residential retaining wall takes one to two hours depending on length and condition. Longer boundary walls or heavily soiled surfaces take more time. We'll give you a realistic timeframe when we quote.
Every one to two years is typical for most Central Coast properties. Walls in heavily shaded areas or those that stay damp tend to need more frequent attention. Once a wall has been properly cleaned, maintenance cleans in future are usually quicker and cheaper.
Get in touch with Coastal Cleans Cleaning Co. for a free quote on retaining wall pressure cleaning anywhere on the Central Coast. We usually respond same day.
