Putting in a retaining wall may be simple on the surface. You need something solid to hold back soil, level out a slope, or neaten the edge of a garden. But what a lot of homeowners do not realise is how complex the job actually is. I learned that the hard way.

Choosing the right retaining wall installation professional is not just about looks. The structure has to be engineered properly, allow for water movement, and suit the soil beneath your feet. Get it wrong and you could be staring at cracks, leaning walls or worse in a few short years.

Here is what to think about before locking someone in.

Start by knowing what your land needs

This is where many people go off track. They see a photo online, love the look, and want the same thing in their own yard. But unless your land has the exact same slope, soil and exposure, that wall might not hold up where you live.

When I first looked into installing one, I thought all I needed was some timber sleepers and a spirit level. But the block I was working with had clay soil, and it shifted more than expected after heavy rain. That could have led to a big failure if I had not checked in with someone who actually understood soil movement.

Make sure your installer talks about drainage, soil type and how high the wall needs to be. If they jump straight to costs without even seeing your site, that is a red flag.

Ask for proof that they know what they are doing

Let’s be honest, anyone can call themselves a landscaper. But when it comes to retaining walls, especially those above a certain height, there are rules around who can legally do the job. You do not want someone guessing with concrete and power tools on your property.

What I asked for:

• A valid licence for structural landscaping
  
  

• Public liability insurance
  
  

• Photos of previous jobs that were similar in scope
  
  

• A few customer names I could call
  
  

The bloke I eventually hired walked me through a job he had done in Ryde just a month earlier. Similar slope, same concrete sleeper design, and drainage done right. That gave me confidence he was the right fit.

Drainage is more important than you think

If your installer shrugs when you mention drainage, walk away. Water is what brings down most retaining walls, not earthquakes or wind.

You need to ask:

• How will water flow away from behind the wall?
  
  

• Will there be gravel backfill and proper piping?
  
  

• What happens when the soil gets saturated in winter?
  
  

If your site is near a boundary, you also need to be careful about runoff. Poor drainage can create legal dramas if water ends up spilling into your neighbour’s yard. There is solid information available from Legal Aid NSW about retaining wall disputes, which breaks down the rights and responsibilities that apply when things go wrong.

Look at materials with a long view

Timber can look great straight after installation, but will it last? Natural stone is beautiful, but it costs more and might not be the best option for a simple backyard wall.

A few options to weigh up:

• Concrete sleepers: strong, clean look, long lifespan
  
  

• Timber: budget option, but needs replacing down the track
  
  

• Stone: high-end finish, more labour
  
  

• Interlocking block systems: great for smaller DIY walls
  
  

In my case, I was tempted by timber because it was cheap and easy. But a neighbour had to rip out his wall after seven years due to rot. I ended up choosing concrete sleepers. Not the fanciest, but rock solid and easy to match with garden beds and paths.

Watch for tricky quotes

When a quote looks too good to be true, it probably is. I had one installer come back with a price half the others—until I read the fine print. It excluded drainage, excavation and even rubbish removal. Basically, he was charging for stacking bricks and nothing else.

Here is what should be on a proper quote:

• Type of materials, listed clearly
  
  

• Labour and expected timeline
  
  

• Drainage setup, including backfill and piping
  
  

• Site prep and cleanup
  
  

• Permits or approvals if required
  
  

Ask for the full thing in writing. If someone is only offering numbers over the phone or text, keep looking.

Connect the wall to your bigger garden vision

This is something I only really understood halfway through my project. The wall is not just a functional structure—it becomes part of your garden’s look and feel. So think about how it ties in with everything else.

• Will it border a lawn, garden bed or pool?
  
  

• Could you include lighting or seating along the top?
  
  

• Will it match existing paving or fencing?
  
  

Even small touches make a difference. I ended up adding low-level solar lights and some sandstone edging, based on garden edging ideas. I came across. It helped the wall feel like a designed feature instead of just a dirt stop.

Ask more than one installer

It is worth talking to at least two or three people. Not just for price comparison, but to hear different takes on what is needed. I had one guy say my site needed full engineering. Another said it was straightforward. The third explained it in simple terms, outlined drainage, and had a solid plan that made sense.

You want someone who listens, explains things clearly, and backs it up with real experience, not just confidence.

See what others have done

Before I got into planning my wall, I spent a couple of nights browsing retaining wall design tips from blogs and forums. Not everything was relevant, but it helped me narrow down ideas and avoid beginner mistakes.

It also gave me a good idea of costs and how long things should take. When someone quoted me a three-day turnaround, I knew that was probably rushed. The average was closer to seven days for walls in the one metre range.

Final thoughts

Retaining walls are one of those things you do not want to redo. They are not cheap, and when done badly, they are even more expensive to fix.

So, take your time choosing a quality retaining wall installer. Ask questions. Walk the site with them. Look at their past work and trust your gut. If someone gives you a bad feeling or avoids details, keep moving.

A solid wall should last twenty years or more. With the right planning and the right person building it, it will not only hold up your garden—it will lift the whole look of your home.