How to Use Crushed Concrete For Flood Landscaping & Drainage

Moreton Bay Recycling yard looking rather wet after the rain.

If you’re in South-East Queensland, the start of this year was probably a bit wetter than you’d like.

Let us refresh your memory…

SEQ Floods February 2022

A road is closed due to the floods, with creek waters covering the bridge

More than 30 locations in SEQ recorded over 1m of rain in a 6-day period, from February 22-28. Here are just a few of the rainfall totals, according to Weatherzone:

  • Bracken Ridge: 1160mm
  • Murrumba Downs: 1145mm
  • Mount Glorious: 1771mm
  • Brisbane: 792.8mm

The waterlogged soil, flooded creeks, and stormwater systems just couldn’t keep up with the sheer volume of water. As a result, many roads, homes, and businesses were flooded or damaged.

Thinking It’s Time to Flood-Proof?

With these ‘1 in 100 year’ events becoming increasingly common (can we truly say 1 in 100 anymore?), you might be wondering how you can be better prepared for next time.

Fortunately, here at Moreton Bay Recycling, we know a thing or two about drainage. Many of our customers specifically use our products for landscaping and drainage projects. And we’ve implemented a number of drainage solutions to minimise the impact of heavy rains around our yard so that we can keep serving customers during wet weather.

Chances are, you’re looking to create a more flood-resistant backyard as soon as possible, but you’re on a budget (due to some unexpected repairs).

So, we’ve put together some ideas that use crushed concrete rock as a more affordable and sustainable product for your landscaping and drainage projects. That way, you can make your backyard or workplace more flood-proof for the future.

5 Ways to Use Crushed Concrete for Flood Proofing

1. Add Fill to Fix Your Slope

A digger moves topsoil around in the Moreton Bay Recycling yard.

Slope issues are often the biggest cause of water flowing or pooling where you don’t want it. If water flowed into your building or washed away your soil and garden during the floods, fixing your slope might be a high priority for you.

One of the simplest ways to fix your slope is by adding fill to any lower lying areas. Bringing up the ground’s level will prevent water from pooling there in future — just make sure that the ground is slightly angled so that any water runs towards your drainage systems.

Before you add your topsoil, try adding a layer of recycled concrete aggregates underneath to help improve the ground’s stability and permeability (allowing more water to soak in more quickly).2.

2. Upgrade Backyard Drainage

A child wearing red gumboots splashes in a puddle.

Did your backyard fill up like a swimming pool during the recent downpours? And was it still squelchy even after a stretch of sunny days? As fun as this would’ve been for the kids, it’s probably a good idea to improve your backyard drainage.

You might like to add some:

  • Channel & Grate Drains – These are set into the ground to collect surface water through a grate, redirecting it to another location, like stormwater drains
  • French Drains – These include a trench with a perforated, sock-covered pipe that’s filled with gravel (or concrete aggregates), allowing water to filter through and flow elsewhere
  • Stormwater Pits – These work like buckets embedded under the surface, covered with a grate, and may be used on their own or connected to drainage systems
  • Open Drains – These are simply an open channel, used to collect and redirect water (line with concrete aggregates for added stability)

Of course, no drainage system is perfect — and if you get a lot of rain in a few short days, you’ll probably still have some sogginess. But hopefully some extra drainage will help your backyard cope a little better next time.

Note: Before doing any major drainage work, be sure to check your local council website for information. In Moreton Bay, you must consider your neighbours when diverting stormwater and ensure that stormwater is not discharged into the sewerage system.

3. Increase Permeable Surfaces

A pile of recycled concrete aggregate.

Installing more drains isn’t the only way to improve your backyard drainage.

Consider replacing your garden paths and pavers with surfaces that absorb water (i.e. are permeable), rather than allowing the water to run off or pool. The more permeable surfaces you have, the less you’ll need to rely on drainage systems that move water away from your home.

Concrete aggregates are a fantastic option for some surfaces, like paths and driveways, whether you use them as a base layer under gravel, or for the whole project. They’re highly permeable, allowing water to seep through to the ground below.

4. Improve Retaining Wall Drainage

Large recycled concrete aggregates

Retaining walls looking a little worse for wear after all the rain?

Heavy rains and flooding are the ultimate test for retaining walls — if you don’t have enough drainage, the right slope, or strong enough materials, pressure can build up behind the wall and cause it to fail.

When repairing a retaining wall, the best approach will depend on the damage you’re dealing with, the type of retaining wall, and the scale of the job. Most of the time, it’s a good idea to call a professional in to ensure the wall is structurally sound and stable enough for your conditions. In some cases, they may need to rebuild from scratch to fix the issues and ensure your wall is built to last.

Here are some general tips for building a strong, flood-resistant retaining wall:

  • Ensure it leans towards the soil it’s holding back
  • Build it on a well-compacted, sturdy foundation
  • Backfill with angular, compactable drainage gravel or aggregate, allowing water to drain through evenly
  • Leave gaps or drainage pipes so that water can escape through the front

Note: Many types of retaining walls must be constructed and engineered by a professional. In Moreton Bay, for example, retaining walls that are 1m above natural ground level; closer than 1.5m to other structures, or load bearing need to be constructed by a certified builder and approved by council.

5. Control and Repair Driveway Erosion

A roller next to a long, rural driveway that is constructed with recycled concrete.

If you have a dirt or gravel driveway, recent heavy rains likely washed a fair bit of it away — and left you with a playground for 4WDs. Perhaps half your driveway even ended up on the road (or further!).

If you prefer a smoother ride up your driveway, you’ll need to do some surface repairs, as well as fix the drainage so your driveway fares better next time. Depending on the condition of your driveway, you may need to:

  • Fill potholes – Remove any soil, leaves, and other debris before patching holes with gravel or aggregate, then compacting with your vehicle
  • Improve your base – Add larger concrete aggregate to your driveway before building your top layer of smaller aggregate or gravel, as these will hold the smaller rocks in place and create a more permeable surface for drainage
  • Top it up – Add another layer of gravel or aggregate to replace the materials that were washed away and increase the height of your driveway
  • Reshape your driveway – Ensure your gravel has a slight pitch at the centre of the driveway so that water quickly runs to the sides
  • Install ditches and drains – If you haven’t already, add drainage ditches (lined with aggregate for added stability) to the sides of your driveway to help move water off your driveway and towards the road

If you have a concrete or paved driveway that’s cracked due to the water logged ground underneath, you might need to pull it up and replace it.

Before re-laying your concrete or pavers, use crusher dust as your base. Because it’s a non-porous material when compacted, crusher dust will stop water from seeping underneath your driveway, reducing concrete shrinking, waterlogging, and water damage.

Get Affordable, Sustainable Flood Landscaping Products

Picture of 75mm concrete aggregates in the Moreton Bay Recycling yard.

Dealing with floods can be an expensive exercise — and like most natural disasters, tricky to plan for.

Fortunately, recycled concrete aggregates offer an affordable solution that you can use in nearly any drainage project. We’re well-stocked with small drainage aggregates in 7mm and 10mm, and larger concrete aggregates in 20mm, 40mm, and 75-100mm sizes. Plus crusher dust, CBR15, CBR80, screened soil, and more — ready to help fix your drainage and repair your yard.

And of course, if you have any concrete waste as part of your flood clean up efforts, be sure to dispose of it responsibly and sustainably at a nearby recycling facility. We’d love to turn your waste into products you can use to help get your yard ready for future flood events (but crossing fingers for no more floods any time soon!).

If you’d like some advice on the best products for your project or want to organise a delivery to your location, give us a call on (07) 3293 4949 on email

See you soon,

– Rory Crundall, Managing Director

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