You've just moved into your new home and there's a white, powdery bloom on the brickwork or the driveway. It's called efflorescence. Most of the time it's cosmetic and fades on its own. Sometimes it's telling you water is getting where it shouldn't, and that's worth knowing while you're still inside your defects period.
What efflorescence is
Efflorescence is a deposit of salts left on the surface of masonry or concrete. Water dissolves soluble salts inside the material, travels to the surface, then evaporates and leaves the salts behind as a white powder or crust.
Those salts can come from the bricks, the mortar, the sand, the concrete or groundwater. The common factor is always water moving through the material.
Why it's common on new homes
New brickwork and concrete are full of construction moisture. As they dry out over the first months, that water carries salts to the surface. It's very common in the first year, especially after a wet spell, and often washes off with rain over time.
If it keeps coming back, or keeps getting worse, look for the water source.
Surface bloom versus salt attack
On the surface, efflorescence is cosmetic. It doesn't weaken the wall or the slab.
The problem is when salts crystallise just under the surface instead. This is called salt attack, and it can make bricks and mortar flake and crumble over time. It's more likely on coastal sites, in salty soils or where walls stay wet. That's why bricks and mortar in those locations need the right salt attack resistance (exposure) grade under AS 3700, the masonry standard.
If you see flaking, spalling or crumbling mortar rather than just white powder, get it looked at.
When it points to a defect
Ongoing efflorescence usually means water is getting into the wall or slab. On a new home, the usual suspects are:
- Blocked or missing weep holes. Weep holes let water drain out of the cavity. If mortar or garden beds block them, water stays in the wall. More on that in what are weep holes.
- Failed or missing flashings over windows, doors and at the base of the wall.
- Garden beds or soil built up above the damp-proof course, which lets moisture wick straight into the brickwork.
- Ground that falls towards the house instead of away from it, so water ponds against the walls or slab edge.
- Leaking gutters, downpipes or taps wetting the same patch of wall over and over.
If you find one of these on a new home, raise it with your builder in writing. Queensland standard contracts give you a 12-month defects liability period from practical completion, so don't sit on it.
The enclosed stage is the best time to check flashings, weep holes and damp-proof courses before they're covered up. Our C11 Enclosed Stage checklist covers it.
C11 - Enclosed Stage Inspection Checklist
$119.00 AUD
Last updated 28 Oct 2026 · Revision 6 · Free updates for life
Checklist Type: Major (Enclosed Stage)
Form Factor: Fillable, print-ready PDF (A4, 42 pages)
When to use: Enclosed (lock-up) stage: brickwork and external cladding
A 152-point enclosed stage checklist for brick veneer and fibre cement, weatherboard or foam cladding. Check the cavity, ties, flashings, windows and lintels before the linings hide them.
How to prevent it
- Keep weep holes clear and keep soil, mulch and pavers below the damp-proof course.
- Make sure the ground and paving fall away from the house.
- Fix leaking gutters, downpipes and taps promptly.
- On concrete and pavers, a penetrating sealer can reduce water absorption. Check it's compatible with the surface and follow the maker's instructions.
- During construction, bricks and sand should be stored off the ground and covered, so they don't soak up salty groundwater or rain before they're laid.
How to clean it safely
- Wait for it to dry. Efflorescence is easiest to remove when dry.
- Dry-brush first. A stiff, dry brush removes most fresh efflorescence. Don't wet it first, or you'll dissolve the salts and push them back into the surface.
- Repeat over a few weeks. New work can keep blooming as it dries out. Brushing it off each time is often all you need.
- Only then try a cleaner. For stubborn deposits, use the cleaner your brick or paver manufacturer recommends. Acids, even diluted vinegar, can etch concrete and mortar and change the colour of some bricks. Test a small, hidden patch first and rinse well.
- Be careful with pressure washers. High pressure can damage mortar joints and the surface of pavers and concrete, and the extra water can bring on more efflorescence.
The short version
White powder on new brickwork is normal and usually goes away. Brush it off dry. If it keeps returning, find where the water is coming from, and if that turns out to be a building defect, report it to your builder within your defects period.
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