Cladding · Brick veneer & concrete block
Painting brick is close to a one-way decision. Make it deliberately.
A third of New Zealand houses are brick, and almost none of them needed to be painted. That is not an argument against doing it — painted brick can look superb and it is one of the few changes that genuinely resets a house. It is an argument for understanding that you are committing the building to a maintenance cycle it did not previously have, and that you cannot change your mind later.
33%
of New Zealand houses are brick-clad — the second-largest group after weatherboard. A national survey figure; there is no per-suburb cladding dataset in New Zealand.
BRANZ Study Report SR456, “Assessing the condition of New Zealand housing” · 2020
The physics
Why breathability is the whole argument
Masonry manages water by absorbing it and letting it go again. Every serious problem with painted brick comes from interfering with the second half of that.
A New Zealand brick veneer is not a waterproof skin. It is a rain screen with a drained and vented cavity behind it. Water strikes the brick, some soaks in, most runs down the outside, whatever gets through drains down the cavity to the flashing and out, and the wall dries by evaporation from the outer face. The system depends on that outer face being able to release moisture.
Now apply a low-permeability coating. Absorption continues — through hairline cracks, through the mortar, from behind. Release slows. Moisture concentrates just under the film. Two things then happen: the film loses adhesion and peels in sheets, and the salts and moisture cycling at that boundary break the fired face off the brick in flakes. Spalled brick cannot be repaired, only replaced.
So the specification for brick is not "exterior paint". It is a vapour-permeable coating system, applied to sound, repointed, dry masonry that is not being fed water from somewhere else. Anything sold as a masonry waterproofer or a sealer is generally the wrong direction entirely.
Concrete block is the easier case
Block was almost never meant to be a final finish, and coating it is ordinary practice. The two things that catch people are alkalinity and porosity. Fresh block and fresh mortar are strongly alkaline and will saponify an unsuitable coating, so it needs curing time and an alkali-resisting primer. And the open texture drinks paint: on bare block, expect the first coat to deliver a fraction of the tin’s stated coverage, and consider a block filler rather than trying to bridge the texture with extra topcoats.
If you go ahead
A brick coating system that behaves
- Fix the water first. Gutters, downpipes, ground and paving clearance, weepholes clear and unpainted. Every one of those is cheaper than a repaint that fails.
- Repoint what has gone. Soft, receded or missing mortar, in a mortar no harder than the brick. A cement-rich repoint on soft old brick pushes the failure into the brick face.
- Wash and treat, then let it dry properly. Masonry holds far more water than timber and takes far longer to give it back. Days, not hours.
- Do not paint the weepholes shut. They are the drainage path for the cavity. This is a small detail that is missed constantly and it disables the wall’s drainage.
- Primer to suit. Alkali-resisting on block and new mortar; a masonry stabilising primer on old, dusty or friable surfaces.
- Vapour-permeable topcoats, two of them. Mineral or silicate systems on older solid masonry; a breathable acrylic masonry system on modern veneer. Confirm the permeability, in writing.
What it will cost you later
Judgement, not data, and stated as such: a painted brick elevation needs repainting on roughly an eight- to fifteen-year cycle depending on exposure, where the unpainted wall needed a wash. That ongoing cost is the real price of the decision, and it is the part that never appears in the before-and-after photos.
The site does not publish a rate per square metre for this, or for anything else, because no official New Zealand source publishes one. Here is the full explanation of that gap, and here is how to estimate your own area so a quoted figure is at least checkable.
Questions people actually ask
Can you paint brick?
You can, and on some houses it transforms them. Understand first that it is close to irreversible. Paint keys into the pores of the brick and the mortar, and there is no way to take it off that does not damage the face — chemical stripping is partial, messy and expensive, and abrasive blasting removes the fired outer skin and leaves the brick permanently more absorbent than it was. Once brick is painted, it is painted, and it now needs repainting every eight to fifteen years for the rest of its life.
Why does breathability matter on a brick wall?
Brick and mortar absorb water and then release it. A New Zealand brick veneer wall is designed around that: water gets in, drains down the cavity, and evaporates out. Coat the outside with a low-permeability film and you slow the release without stopping the absorption — moisture then accumulates, and in the worst case it freezes or crystallises just under the film and pops the face off the brick in coin-sized flakes. That is spalling, and it is permanent. Coatings for brick need to be vapour-permeable, which rules out most ordinary exterior paints and all sealers marketed as waterproofing.
When should I definitely not paint my brick?
Four cases. Where the brickwork is already spalling or the mortar is soft and crumbling, because paint seals a decaying wall rather than repairing it — repoint first. Where there is persistent efflorescence, the white salt bloom, because that means water is moving through the wall and has to be traced first. Where the house is in a Special Character Area or is a scheduled historic heritage place and the brickwork is part of what is protected, in which case painting the street elevation may need resource consent. And where you are doing it because a wall looks dirty, which is a job for washing.
What about painting concrete block?
Block is the more straightforward of the two and painting it is normal practice — it was rarely intended to be a finished surface. New block is strongly alkaline and needs to cure before coating, and it needs an alkali-resisting primer. It is also porous enough that the first coat largely disappears into it, so the quantity for a bare block wall is well above the tin’s stated coverage. Filling the open texture properly usually means a block filler rather than an extra topcoat.
How do I get rid of the white powder on my brick?
Efflorescence is mineral salt left behind when water moves through masonry and evaporates at the surface. Brushing it off dry and letting the wall dry out deals with a light bloom on new brickwork, which is normal and self-limiting. Efflorescence that keeps returning on an established wall is a symptom, not a stain: something is putting water into that masonry — a leaking gutter, a broken downpipe, a blocked cavity, ground built up against the wall, a failed damp course. Find that first. Painting over it traps the salt behind the film and it will lift the film off.
Is limewash or mineral paint different?
Yes, and on older solid masonry it is often the better answer. Mineral coatings — limewash and silicate or mineral paints — bond chemically with the masonry and stay highly vapour-permeable, so the wall keeps breathing. They look different from an acrylic finish, being more matte and more variable, and that variability is the point on a heritage building. They are less common in New Zealand residential work than they should be, so specify them deliberately rather than assuming a quote includes them.
Related
Brick-and-tile houses usually raise the roof question at the same time — concrete tile, pressed metal and Decramastic are here. And if the brickwork is on a house with a plastered addition, read the plaster page before you book anything.