Efflorescence & Salt Damage
White crystals on your walls are not just ugly — they are telling you salt is inside the brickwork, and it is destroying it from within.
Efflorescence is the white crystalline deposit on masonry — it is salts being carried to the surface by moisture and crystallising as water evaporates. On its own it is harmless, but it signals water is moving through your wall. When salts crystallise inside the wall instead of on the surface — usually because a non-breathable render or paint is trapping them — they expand, spalling bricks and mortar. Fixing it means dealing with the moisture source and using breathable materials. Romans Building Services assesses efflorescence & salt damage across Sydney before recommending repair, so the visible damage and the cause are both dealt with.
Last updated: 2026-05-29
What is efflorescence & salt damage?
Efflorescence is the white fluffy deposit you see on brick and masonry walls. It is actually salts — natural salts from the bricks, mortar, or ground — being carried to the surface by moisture in the wall and crystallising when the water evaporates. On its own the white deposit is harmless and can usually be brushed off. The problem is what it tells you: water is moving through your wall carrying dissolved salt.
When salts crystallise inside the wall instead of on the surface — because a non-breathable render or paint is trapping them — they expand. That expansion pushes render off, cracks brick faces, and blows mortar out of joints. This is called salt attack or salt decay, and it is one of the main reasons coastal Sydney brickwork fails.
The fix is never just cleaning the surface. You have to deal with the moisture source, let the wall breathe, and sometimes apply specific salt-treatment systems so existing salts can leach out without causing more damage.
Signs to look for
- White fluffy crystals on the surface of brick or render
- Salt deposits reappearing after you brush them off
- Brick faces flaking, spalling or turning powdery
- Mortar crumbling where salt deposits are worst
- Paint or render bubbling and peeling in patches
- Damp patches inside walls with salt staining on internal finishes
- Worst on coastal-facing walls or walls near the ground
Why it happens
- Salt in the air crystallising in brick pores (coastal suburbs)
- Rising damp carrying ground salts up through the wall
- Leaking pipes or drains depositing salt through the brickwork
- Cement mortars and renders trapping salts against soft brick
- Waterproof paint sealing moisture and salts into the wall
- New building — salts in fresh mortar working their way out (usually self-limiting)
How urgent is this?
Minor surface efflorescence on a new wall usually self-resolves within a year or two. Ongoing efflorescence on an older wall, or any signs of brick faces spalling or mortar failing, means there is an active moisture problem that will keep damaging the wall until it is fixed. Not an emergency, but not something to ignore either.
How we fix it properly
Identify the moisture source
Salt needs moisture to move. We find where the water is coming from — rising damp, leaking pipe, poor drainage, failed waterproofing, coastal exposure. The fix starts with stopping the water.
Remove failed finishes
Cement render, waterproof paint, impermeable coatings — anything trapping salts in the wall comes off. We use breathable systems in their place.
Allow the wall to dry
With the moisture source stopped and impermeable finishes removed, the wall needs time to dry out. For heritage walls this can be months, and drying naturally is the right approach rather than trying to force it.
Neutralise salts where needed
For badly salt-contaminated walls, we apply specialised salt-retarder systems — clay poultices or sacrificial renders that pull salts out of the brick and into material that can be removed.
Restore with breathable materials
Repointing with appropriate lime mortar, breathable render where needed, and mineral-based paint that lets the wall continue to breathe. Damaged bricks replaced with matched stock.
Typical cost range
Depends heavily on scope. Cleaning and minor repair $1,500 – $4,000. Full salt-damage restoration on a heritage wall $8,000 – $25,000+.
Every job is different. We give a firm quote after inspection.
Common questions
Can I just scrub the salt off with a wire brush?
For cosmetic efflorescence on a new wall, yes — brush it off dry, do not use water (water just dissolves and re-deposits the salt). For ongoing salt damage on an older wall, scrubbing the surface does nothing to the underlying problem. The salts keep coming because the water keeps moving through the wall.
What is the best paint for a coastal brick wall?
Breathable mineral paint — silicate or lime-based. Never acrylic or waterproof paint on old brick, because they trap moisture and salts behind them, which is exactly what you do not want.
Why does my render have salt coming through even though it is new?
The salt is either rising from the ground (missing or failed damp course) or coming through from the brick behind the render. New render on a wall with ongoing salt issues will fail again in a few years unless the underlying moisture and salt problem is dealt with first.
Is efflorescence the same as concrete cancer?
No, but they are related. Efflorescence is salt deposits on masonry. Concrete cancer is rusting steel inside concrete. Both are caused by moisture and salt — but efflorescence is usually a masonry problem, and concrete cancer is a concrete-and-steel problem. A coastal apartment block often has both.
Services that fix this
Efflorescence & Salt Damage in your area
The causes and right fix for efflorescence & salt damage vary with local housing stock and exposure. Read the version closest to where you are:
Where we see efflorescence & salt damage 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 efflorescence & salt damage?
Send a photo or call Minas directly. We will tell you straight whether it needs doing now, or whether it can wait.