Cladding · Plaster, stucco, EIFS, texture coat
If water has got into the wall, paint is the last of your concerns.
This is the highest-stakes page on this site, so it is going to be blunt. A monolithic-clad house can be repainted beautifully and correctly. But the decision about whether to repaint it at all should be made after a moisture investigation, not after a colour consultation — because on this cladding family, a new coating can conceal the only evidence you had.
95%
Estimated weathertightness failure rate for monolithic and stucco cladding, against 2% for weatherboard. National estimates for the 1992–2005 build period, not a finding about any individual house — but the reason this substrate gets investigated before it gets quoted.
First, what have you actually got
Four systems that look like one
They all read as a single continuous rendered surface. The repair and coating decisions differ sharply, and so does the risk profile.
Traditional stucco (roughly 1910–1960)
Sand-and-cement plaster applied in coats over netting or timber lath on a solid backing. Thick, hard, heavy, and generally the best-behaved of the four — it has been standing for decades and the framing behind it is usually old-growth timber that has had a chance to dry between wettings. Its cracks are mostly shrinkage and settlement. It is genuinely repairable.
Cement plaster over fibre-cement backing (1990s onward)
A thinner plaster system over sheet. Whether it performs depends almost entirely on details you cannot see from outside: whether there is a drainage cavity behind it, whether the flashings were installed to a recognised detail, and whether the framing was treated. This is the group at the centre of New Zealand’s weathertightness problem.
Texture-coated fibre-cement sheet
Sheet cladding with a textured coating applied over it, with the sheet joints stopped so they disappear. The joints are the vulnerable point: they move, and when the stopping fails the crack follows the joint line in a dead-straight run. That straightness is the diagnostic.
EIFS — render over polystyrene
A reinforced render coat over expanded polystyrene sheet. Light, well insulated, and unforgiving of penetration, because the polystyrene has no structural resistance to a fixing or an impact and water that gets past the render has an easy path. Fixing anything to an EIFS wall — a hose reel, a light, a balustrade — is a genuine risk and needs a proper detail, not a plug.
PwC for the Department of Building and Housing, “Weathertightness — Estimating the Cost” · 2009
The sequence that matters
Readings, then findings, then specification. Colour last.
Here is the order a competent job follows on monolithic cladding, and it is worth insisting on it even when it delays your repaint by a fortnight.
- Non-invasive moisture readings, systematically. Every window and door junction, the base of every wall, deck and balcony junctions, parapets, penetrations, and every place the cladding meets a different material. Recorded, not eyeballed.
- Clearances and details checked. Ground clearance, paving clearance, deck junctions, whether there is a drainage cavity, whether head flashings exist over the windows.
- Findings in writing, before any quote. If the readings are elevated, the next step is a building surveyor and possibly invasive readings — not a painter’s deposit.
- Then, and only then, the coating specification. Crack repair method, reinforcement where needed, sealer, and the film build of the membrane, all written down.
Reading the cracks
Not all cracks mean the same thing, and the pattern is informative:
- Fine map-pattern crazing across a whole wall. Usually the coating, usually cosmetic. This is what a high-build flexible membrane is designed for.
- Straight cracks following a grid. Sheet joints moving. The stopping has failed. It needs the joint treated as a joint, not filled as a crack.
- Diagonal cracks from window and door corners. Structural movement or an inadequately detailed opening. Investigate.
- Cracks with staining, efflorescence or a soft edge. Water has been through them. Investigate. Do not coat.
- Horizontal cracks at a floor line, or cracks that step. Movement. Investigate.
When it is genuinely a paint job
Sound monolithic, done properly
Plenty of Auckland plaster houses are dry, sound and simply tired. On those, this is what a real specification looks like — and it is not the same product as a weatherboard repaint.
- Wash and treat. Plaster holds mould in its texture. Treat, dwell, rinse, dry back.
- Route and repair live cracks. Open them out, fill with a flexible cementitious or polymer repair compound, reinforce the patch with mesh tape where the crack is on a joint line, and texture-match the repair before coating.
- Re-seal the junctions. Window and door perimeters, control joints, penetrations. A low-modulus flexible sealant, applied to a properly prepared joint with the right depth-to-width ratio — not a bead squirted over the old one.
- Sealer coat. Alkali-resisting on new or repaired plaster; a stabilising sealer on old, chalking, friable coatings.
- High-build flexible membrane, at the stated film build. The film build is the whole product. Applied thin to make the litres go further, an elastomeric coating is just expensive paint. Ask for the wet film thickness and the spreading rate in writing.
Ask for these four things in writing
- The moisture readings, with where each one was taken.
- The crack repair method, by crack type.
- The product name and the specified film build or spreading rate per coat.
- What is excluded — because on monolithic cladding, the exclusions are where the money is.
None of that is unreasonable to ask, and a contractor who works on this cladding regularly will have it to hand. The surface-area estimator will tell you roughly how many square metres you are talking about, which makes a quoted litre figure checkable.
Questions people actually ask
What exactly is monolithic cladding?
Any cladding that presents as one continuous, jointless surface rather than as overlapping boards or sheets. In New Zealand it covers traditional stucco over netting or lath, cement plaster over fibre-cement backing sheet, texture-coated fibre-cement sheet, and EIFS — a rendered coating over polystyrene sheet. They look almost identical from the footpath and behave very differently, which is part of the problem.
Is a crack in my plaster serious?
It depends entirely on what kind of crack it is. Fine, shallow, map-pattern crazing in the coating is usually cosmetic and is what a high-build membrane exists to bridge. A single straight crack running from a window corner, a crack you can fit a fingernail into, a crack with staining or efflorescence around it, or one that steps at a change of level — those are structural or water-related and filling them is not the fix. The distinction is not something to make from a photo.
Should I paint over the cracks or fix them first?
Fix first, always, and fix according to what is causing them. Routing out a live crack, filling with a flexible repair compound and reinforcing the patch is a real repair. Skimming filler across the surface and coating over it is decoration, and the crack will reappear in the same line during the first big temperature swing — usually within a year, and usually more visibly than before because the new film is thicker.
What does a moisture investigation involve, and do I need one?
On a monolithic-clad house being repainted, yes. At minimum, non-invasive meter readings taken systematically at every window and door junction, at the base of every wall, at deck and balcony junctions, at parapets, and anywhere the cladding meets another material. A building surveyor doing this properly will also check ground and paving clearances, whether the cladding has a drainage cavity, and whether the flashings were installed to a recognised detail. Invasive readings — small drilled holes into the framing — are the definitive test where the non-invasive readings are elevated.
Can painting make a leaky building worse?
Yes, and this is the part nobody says out loud. Monolithic walls that get wet rely on drying out. A thick, low-permeability coating applied over a wall that already has water in the framing slows that drying, and it hides the surface evidence — the staining and the efflorescence — that a surveyor would otherwise read. You end up with a house that photographs well and rots quietly. That is why the moisture readings come before the specification, not after.
What is an elastomeric or high-build membrane, and do I need one?
A thick, flexible, crack-bridging coating applied at a much higher film build than ordinary house paint — measured in hundreds of microns rather than tens. On sound monolithic cladding with cosmetic crazing it is the right product, because it accommodates movement rather than cracking with it. It is not waterproofing and it is not a substitute for flashings, and on a wall with an actual water-entry path it makes the situation worse, not better.
How do I know whether this is a paint job or a reclad?
The moisture readings decide it, not the appearance. Dry framing, sound substrate and cosmetic crazing is a paint job with a proper repair and membrane specification. Elevated readings, decayed framing, missing or incorrect flashings, or a cladding system with no drainage cavity where one is now required is building work — very likely restricted building work under the Building Act 2004, which must be carried out or supervised by a Licensed Building Practitioner. That is the recladding conversation.
If the readings come back wet
Recladding, targeted repair, flashings and framing — the work that comes before paint, and the consent path it needs.
Renovate Auckland — recladding