Before You Buy: 10 Silent Structural Clues That Can Make or Break Your Development

Adam Bahrami
Sep 10
3 min read

Updated: Sep 15

In property development, the numbers might stack up, but if the structure doesn’t, you’re in trouble.

We’ve seen it too many times. An investor finds a “perfect” block for a duplex. The zoning looks good. The DA potential checks out. But just beneath the surface? Costly surprises that kill the project before it starts, uneven floors, corroded steel, or foundations that are already on the move.

So here’s what we’ve learned over decades of buying, building, and fixing development sites across Sydney and Queensland. 10 things to look for that don’t show up on a realestate.com.au listing, but should absolutely shape your due diligence.

1. Cracks: Not Just Cosmetic

Hairline cracks are common, especially in older homes. But if you’re seeing wide gaps, diagonal patterns, or anything near doors and windows, pause before you proceed. These could be signs of soil movement, slab shift, or a poor original build, any of which could lead to major underpinning work later.

2. Sloping, Uneven or Bouncy Floors

A slight slope might not bother a homebuyer, but for a developer? It’s a red flag. Floors that bounce or slope can point to frame movement, water damage, or even termite activity. If it’s a timber subfloor, be extra cautious, once the joists are compromised, the costs pile up quickly.

3. Doors and Windows That Don’t Behave

This one’s subtle, but important. Do internal doors swing open on their own? Are windows jamming in the tracks? You might be dealing with frame distortion or foundational issues. These quirks can signal broader movement across the house.

4. Rooflines That Dip or Wave

Step back across the street. Look at the roofline. Is it straight and level, or do you see a slight dip? Roof structure failure, particularly in older homes, is an expensive fix. Don’t get caught thinking it’s “just the tiles”, check the frame underneath.

5. Signs of Moisture, Damp or Mould

Bathrooms and laundries aside, signs of water staining, soft spots in walls, or musty smells deserve investigation. Water and structure don’t mix, once moisture sets into framing or supports, the rot process begins. Especially with old waterproofing or bad drainage, this can quickly turn into a rebuild scenario.

6. Termites: The Hidden Demolition Crew

The home might look fine. But behind the walls, termites could be eating it alive. Even past termite damage, if untreated, could mean weakened beams or joists. Always get a pest inspection. In many areas, it’s not a question of if termites are nearby, but when they’ll show up.

7. Rusted Steel = Long-Term Headache

In certain homes, particularly brick or mixed-material builds, look out for steel lintels, beams, or supports. If rust has already taken hold, the steel might be expanding, cracking surrounding brickwork or concrete. These fixes aren’t cosmetic, they’re structural, and often costly.

8. Water Flow (Or Lack of It)

You might be inspecting the inside of the house, but what’s happening outside matters just as much. Poor site drainage can lead to slab movement, erosion, or damp crawlspaces. If water pools near the slab after rain, you’ll likely face moisture or movement issues in future.

9. DIY Work That Shouldn’t Have Been Done

It’s easy to spot: mismatched tiles, awkward joins, or crooked fixtures. But bad renovations can go deeper than just bad taste, they often hide poor structural or electrical work underneath. If the visual finish is messy, you have to ask what else they cut corners on.

10. Something Just Feels… Off

Sometimes, it’s not a technical sign. It’s a gut feeling. A house that feels “off balance”, uneven ceiling heights, weird room angles, strange shadows, often has structural oddities that are hard to fix. Trust your instincts, but verify with an expert.

Why This Matters So Much for Developers

Most of these issues won’t kill a home sale, but they can kill your feasibility.

Cost blowouts from unexpected slab works
Structural defects that delay or derail DAs
Resale limitations from underlying damage
Or worst, a rebuild that wasn’t in the budget

In the development game, margin is everything. And missing one structural warning sign can turn a profitable duplex project into a money pit.

OwnerDeveloper’s Take

We’ve walked hundreds of sites. We’ve seen clients win, and lose, based on what they catch or miss before buying. That’s why structural due diligence is non-negotiable.

If you’re not sure what to look for, or how to evaluate risk properly, that’s exactly where we come in. From site inspections to full feasibility and design guidance, we help our clients make smarter, safer decisions before they sign anything.