Spalling & Falling Render
Render does not fall off healthy walls. When it does, the wall underneath is usually the real problem.
Render that is bubbling, cracking or falling off is almost always a symptom of something going wrong underneath — salt in the masonry, trapped moisture, or a render mix too rigid for the wall behind it. Coastal Sydney walls and cement render on old soft brick are the most common causes. A proper fix means removing all failed render, treating the substrate, and re-rendering with a breathable system matched to the wall — not smearing new cement render over the same problem. Romans Building Services assesses spalling & falling render across Sydney before recommending repair, so the visible damage and the cause are both dealt with.
Last updated: 2026-05-29
What is spalling & falling render?
Spalling render is render that is lifting, bubbling, cracking or falling off in patches. It is almost never a render problem on its own — it is a symptom of something happening underneath. The most common causes are salt in the masonry, moisture trapped behind the render, or the render being bonded to a wall that cannot support it properly.
In coastal parts of Sydney — Bondi, Manly, Dee Why — salt crystallising between the render and the brickwork pushes the render off from behind. In older Inner West and Eastern Suburbs terraces, cement render was applied over soft handmade brick in past decades, and the resulting moisture trap is blowing the render off 30 to 60 years later.
A proper fix means working out why the render failed, dealing with that cause, and re-rendering with a material matched to the wall. Smearing new cement render over the same problem means it falls off again in a few years.
Signs to look for
- Render bubbling or hollow-sounding when tapped
- Large sheets of render detaching from the wall
- Cracks around the edges of render patches
- White salt deposits (efflorescence) on or behind render
- Paint peeling along with the render
- Damp patches inside walls where render has failed outside
Why it happens
- Salt crystallisation behind the render (common in coastal Sydney)
- Cement render on soft old brick, trapping moisture
- Rising damp pushing moisture up through render
- Poor original bond — render applied without proper preparation
- Wrong mix — too strong, too rigid, or poor-quality aggregate
- Failed waterproofing above the rendered area letting water run behind
How urgent is this?
If render is only bubbling, you have time. If sections are actively falling off — especially on street frontages or above walkways — it becomes a safety issue. Once it starts going, it usually accelerates. Get it inspected so you know the scope.
How we fix it properly
Full inspection
We tap every section to find hollow render — the stuff you can see is only part of it. We identify the cause: salt, damp, wrong mix, poor bond. The repair scope depends on the cause.
Remove all failed render
Everything hollow or loose comes off. We cut back to sound render with clean edges. Leaving weak render next to new work means the new work fails at the join.
Treat the substrate
Wash out salts, let the wall dry, and apply a salt-resistant primer if needed. On heritage brick, we often apply a breathable lime bedding coat so the render bonds properly without trapping moisture.
Re-render with the right material
On heritage buildings, lime-based render. On modern masonry, an appropriate cement render with the right flexibility. On coastal walls, salt-resistant render. We match the finish — roughcast, float, bagged — to what is already there.
Apply breathable protective coating
Breathable masonry coating or mineral paint keeps water out while letting the wall breathe. Acrylic paint on lime render traps moisture — we never use it. The right finish keeps the repair looking right for decades.
Typical cost range
$150 – $350 per square metre depending on wall type, access, and whether heritage-grade materials are needed.
Every job is different. We give a firm quote after inspection.
Common questions
Can I just re-render over the bubbling areas?
No. Render laid over failing render will fail too, usually faster. You have to remove all the failed render, treat the cause, and re-render properly. Shortcutting this step means you pay twice.
Why did cement render get used on my old brick house?
In the 1960s to 1980s it was common to cement-render older brick houses — seen as modernising them. Nobody thought about the fact that soft lime-mortared brick walls need to breathe. 30 to 50 years later, the damage is showing up. Correcting it means going back to breathable lime-based materials.
What is the right render for a coastal home?
A salt-resistant, breathable render — lime-based for heritage, polymer-modified for modern. We use products that let moisture escape from the wall without letting salt build up behind. Standard cement render in Bondi or Manly is a 10-year fix.
Can I just paint it instead of re-rendering?
If the render is sound but just faded or tired, yes — a breathable mineral paint can refresh it. If the render is bubbling, cracking or falling off, painting is pointless. Fix the render first, paint last.
Services that fix this
Spalling & Falling Render in your area
The causes and right fix for spalling & falling render vary with local housing stock and exposure. Read the version closest to where you are:
Where we see spalling & falling render most often
Some suburbs have more of this problem than others — the local housing stock, age, and coastal exposure all play a part. Click through for the local context.
Think you might have spalling & falling render?
Send a photo or call Minas directly. We will tell you straight whether it needs doing now, or whether it can wait.