Why standard building inspections miss waterfront issues
Building inspectors in Queensland are licensed to assess the condition of structures on the land. Most of them are not marine contractors, they don't carry boats, and they're not assessing the waterway boundary as part of a standard inspection.
This isn't a criticism of building inspectors. It's just a structural gap in the process that most buyers don't know exists until after settlement.
The revetment wall at the water's edge is typically the most expensive maintenance liability on a waterfront property. It's also the one thing the building inspection report is least likely to cover in any meaningful depth.
A standard inspection might note that a revetment wall "appears sound" based on a visual observation from the top of the bank. What it won't tell you is whether the base of the wall has eroded, whether there are voids behind it, whether the footing has moved, or whether the wall is five years from needing full replacement.
Those are not small omissions. A revetment wall replacement on a standard canal allotment in SE Queensland is a significant cost. Discovering that liability six months after settlement, when the wall starts visibly moving, is a very different experience to knowing about it before you made your offer.
What to look for before you make an offer
You don't need to be a marine engineer to do a useful preliminary assessment of a waterfront property. You need to know what to look for and where to look.
Get to the water's edge and look down
Most buyers walk to the back fence, admire the view and move on. Take the extra two minutes to actually get down to the water's edge if you can access it, and look at the face of the revetment wall from above. You're looking for visible cracks or horizontal displacement in the wall panels, sections that have bowed outward toward the water, gaps between panels where you can see soil behind them, and any sign of the wall having moved since it was built.
None of these signs is automatically a dealbreaker. But any of them warrants a closer look before you commit.
Look at the ground behind the wall
Step back from the edge and look at the surface immediately behind the revetment wall. Subsidence behind the wall often shows up as a low point or depression running parallel to the water's edge. Cracking in paving, a garden bed that's sitting lower than it should be, or fencing that's tilted toward the water are all signs that the ground behind the wall has lost material.
This is particularly worth checking on properties that have large paved entertaining areas or pools close to the water's edge. A void developing beneath a pool surround that sits two metres from the canal is not a problem you want to discover post-settlement.
Look at the base of the wall from the water side
This is the step that almost never happens during a standard property inspection and it's the most important one.
If the property has a jetty or pontoon you can access, walk to the end of it and look back at the revetment wall at water level. At low tide especially, you'll see the base of the wall in a way that's completely invisible from the bank above. You're looking for erosion at the toe of the wall, sections where the base has undercut, and any displacement of rock armouring or base material.
If you can't access the water side from the property, ask the agent whether you can view at low tide from a neighbour's jetty, or arrange to have someone take a look from a boat. Any vendor or agent who objects to that request on a waterfront property should make you ask why.
Check the age of the wall
Ask the agent or the vendor directly: when was the revetment wall last repaired or replaced, and is there any documentation for that work?
Canal estate properties built in the 1970s and 1980s on the Gold Coast and in the Redlands often have original revetment walls that are 40 to 50 years old. Some of those walls have been well maintained. Others have had cosmetic work done on the visible face while the structural issues at the base were never addressed.
If the vendor can't provide any documentation for wall maintenance or repair, factor that uncertainty into your offer price or your due diligence process.
The properties that carry the most risk
Not all waterfront properties carry equal risk, and knowing which types warrant extra scrutiny will save you time.
Properties on high-traffic canals carry more risk than those on quieter waterways. Repetitive boat wash against the bank is a slow but persistent cause of revetment wall erosion, and properties that have been exposed to decades of heavy canal traffic often show more base erosion than their neighbours on quieter stretches.
Properties with large structures close to the water's edge, pools, entertaining areas, outbuildings, carry more risk simply because the consequences of wall movement are more severe. A lawn that subsides is inconvenient. A pool that starts cracking because the ground beneath it has moved is a different conversation entirely.
Older properties that have changed hands multiple times without any documented wall maintenance are worth extra scrutiny. Each owner may have deferred the issue, and you may be the buyer who inherits several decades of accumulated problem.
Properties on bends or points where water movement is more complex than a straight canal run carry more erosion risk at the base, particularly on the outside of a bend where current tends to concentrate.
What a pre-purchase waterfront assessment involves
If you've done a preliminary visual assessment and found anything that concerns you, or if you're buying a property with an older revetment wall and you want a clear picture of what you're taking on, a pre-purchase waterfront assessment is worth the cost.
This is a specialist inspection carried out from the water side as well as the land side, ideally at low tide, by a contractor who works on these structures regularly. It's different from a standard building inspection and it's not something a general building inspector can provide.
A proper assessment will tell you the current condition of the revetment wall, whether there's evidence of voiding or subsidence behind it, what the likely maintenance or repair requirements are in the short to medium term, and whether anything warrants immediate attention.
That information is genuinely useful in a negotiation. A property with a revetment wall that needs significant work in the next two to three years is a different financial proposition to one with a recently repaired wall in good condition. Knowing which one you're buying before you sign the contract gives you options. Finding out afterwards doesn't.
A word for real estate agents and buyers advocates
If you regularly facilitate the sale of waterfront properties in SE Queensland, building a pre-purchase waterfront assessment into your due diligence recommendations is worth considering.
A buyer who discovers a significant revetment wall liability six months after settlement is not a happy client. A buyer who went in with clear information, adjusted their offer accordingly and settled without surprises is much more likely to refer you to the next waterfront buyer in their network.
We're happy to discuss what a pre-purchase assessment involves and how to incorporate it into your process.
What to do if you've already bought and you're not sure what you have
If you've recently settled on a waterfront property and this post has made you want to take a closer look at your revetment wall, the most useful first step is a low-tide inspection from the water side.
Walk to the end of your jetty at the lowest tide of the month and look back at the base of the wall. Take photos. If you see anything that looks like erosion at the base, displacement of rock or base material, or sections of wall that appear to have moved, send us the photos and we'll give you an honest read on what you're looking at.
Twenty years on SE Queensland waterways means we've seen most of what these structures do over time. We'd rather help you understand your wall early than get a call once it's become urgent.
About Gold Coast Barges Gold Coast Barges is a waterfront construction specialist operating across South East Queensland. We work with private waterfront owners, body corporates, builders, landscapers and councils on canal estates and tidal waterways from the Gold Coast to Moreton Bay. Our services include revetment wall repair and replacement, rock armouring, screw piling, beach reprofiling, pontoon dredging and marine construction. Our vessels hold current commercial ship survey certification.