Here is the single most useful thing anyone will tell you about peeling paint, and it is going to sound unhelpful before it sounds helpful.
The paint is not the problem.
Peeling, flaking and bubbling are symptoms. They are the building telling you that something underneath the paint has gone wrong, and the paint film is simply the first thing to give way. Sand it back, put two nice coats over the top, and you have treated the symptom while leaving the cause exactly where it was. It will come back, usually within a year or two, usually in the same spot, and by then you will be convinced that painters are all the same.
So before you buy a single litre of anything, work out what your house is actually telling you.
First, Read the Failure
You can learn most of what you need to know in about five minutes with your fingernail and a torch. Here is what to look for.
Peel a flake off and turn it over. This is the most informative thing you can do. If the back of the flake is clean and you can see bare substrate underneath, the paint never bonded to the surface in the first place. That is an adhesion failure, and it almost always points to preparation: the surface was dirty, chalky, damp, glossy or simply not primed. If instead the back of the flake has another colour of paint stuck to it, and there is still paint on the wall underneath, then the coats have separated from each other. That is an interlayer failure, which usually means incompatible products or a glossy old coat that was painted over without being sanded or sealed.
Press a bubble. If it is soft, springy or damp, there is moisture behind it. If it is hard and brittle, and the paint underneath is intact, it is more likely a solvent or heat blister from the paint being applied in conditions that were too hot.
Note where it is happening, not just that it is happening. Location is diagnosis. Paint failing in the bottom half metre of an old brick wall is a completely different story to paint failing on a bathroom ceiling, which is a different story again to paint failing on one wall of an otherwise fine house.
Rub the surface with a dark cloth. If it comes away with a chalky, powdery film on it, the existing coating has weathered out and is chalking. You cannot successfully paint over chalk. It needs to be washed off and the surface bound with a sealer, or the new coat is sitting on dust.
The Diagnosis Table
| What you are seeing | Where it usually shows up | The likely cause | What actually fixes it |
|---|---|---|---|
| Bubbling that is soft or damp to touch | Under windows, below gutters, on ceilings under a bathroom or roof | Moisture getting in from behind the paint film | Find and fix the water source first. Flashing, gutter, seal, downpipe, roof. Then let the substrate dry fully before any coating |
| Bubbling in the bottom half metre of an old masonry wall, with white powder | Ground floor walls of older brick homes | Rising damp and salt attack, no damp course or a failed one | This is a building issue, not a painting one. A builder or damp specialist first. Painting over it will fail again, and a film forming coating can make it worse by trapping moisture |
| Flaking in sheets, bare substrate on the back of the flake | Anywhere, but especially previously painted brick and render | Adhesion failure. Surface was chalky, dirty, damp or unsealed when painted | Remove all failed coating back to a sound edge, wash, seal or prime correctly for the substrate, then recoat |
| Flaking with old paint stuck to the back of the flake | Doors, windows, skirtings, architraves, trims | Interlayer failure. Water based paint applied over old oil based enamel that was not sanded or bonded | Remove the failed coats, sand the old enamel back properly, apply an appropriate bonding primer, then topcoat |
| Peeling on a bathroom or laundry ceiling | Directly above a shower | Steam and no ventilation. The film has been repeatedly soaked | Fix the ventilation first. Then strip, treat any mould, seal, and use a coating designed for wet areas |
| Fine cracking and flaking with a chalky powder | Sun facing exterior walls, older coatings | Normal end of life UV degradation and chalking | Wash off the chalk thoroughly, apply a binding sealer, then a modern exterior system |
| Rust staining and paint lifting around metal | Steel lintels, balustrades, window frames, fixings, coastal homes | Corrosion under the film | It is a rust problem, not a paint problem. Take the metal back, treat and prime with the correct metal primer, then recoat |
| Hard, brittle blisters on a hot wall | West facing walls, dark colours, applied in summer | Paint applied to a surface that was too hot, so the film flashed off before it formed | Remove the affected film, and reapply following the shade, within the manufacturer stated temperature range |
| Widespread flaking on new render or masonry | Newer builds and recent render work | The substrate was coated before it cured, and the alkalinity attacked the film | Allow proper curing, remove the failed coating, use an alkali resistant sealer, then recoat |
Fix the Cause Before You Touch the Paint
If your diagnosis points to water, stop. Do not sand, do not fill, do not prime. Every hour spent painting over an active leak is wasted, and you will not know it is wasted until months later.
The usual suspects are boring and findable. A blocked or rusted gutter overflowing behind the fascia. A downpipe discharging against a wall. Failed sealant around a window frame. A cracked roof tile or failed flashing letting water into a ceiling cavity. A shower with no exhaust fan, or with one that vents into the roof space rather than outside, which simply moves your problem into the ceiling.
Once the source is fixed, the substrate needs to dry out properly. That takes longer than people think, and on masonry it can take weeks. Painting a damp wall is how you end up doing this all again.
If the failure is in the bottom of an old brick wall and it is accompanied by white crystalline powder, that is likely rising damp and salt attack. That belongs to a builder or a damp specialist, not to a painter, and we will tell you so rather than take the job. It is one of the few situations where paint can genuinely make things worse, because a film forming coating traps moisture in the wall and drives the problem further up.
How to Repair It Properly
Once the cause is dealt with and the surface is dry, the repair itself follows a sequence that does not change. It is the same sequence whether we are doing interior painting or a full exterior repaint. This is the part where most jobs are quietly lost.
Remove everything that is not stuck. Not just the flakes that fall off when you look at them. Scrape and sand until you reach paint that will not lift when you push at it. This almost always means taking off more than you wanted to. Every square centimetre of loose paint you leave behind is a place your new coating will fail from.
Feather the edges. This is the step people skip and then wonder why the repair is visible from the doorway. Where the sound paint meets the bare patch there is a step, sometimes several coats thick. If you paint over that step, you will see it under raking light forever. It needs to be sanded back to a smooth taper so the transition disappears.
Wash and treat. Remove chalk, dirt, salt and grime. If there is any mould, it must be killed rather than removed. Scrubbing mould off and painting over it leaves the spores in place and it will bloom back through the new film, often within a season. This is the single most common reason exterior repaints disappoint on shaded, leafy Sydney streets.
Prime the bare areas with the right primer. The word right is doing a lot of work in that sentence. Bare timber, bare plasterboard, bare masonry, chalky render and rusted steel all need different products, and using a general purpose undercoat everywhere is a big part of why paint fails in the first place. Sealers and primers are the least glamorous line on a quote and the most load bearing.
Then paint. In the number of coats the surface actually needs, which on a spot repair is usually more than you think, because the repaired area will absorb differently to the surrounding wall.
Expect the repair to show if the wall is old. Honest word here. Colour fades. A patch repaired with the same tin the wall was painted with eight years ago will not match the wall, because the wall has moved and the tin has not. Very often the correct answer is not to patch it but to recoat the full wall or full elevation, cutting at a natural break like a corner or a window line. It costs more on the day and it looks like a house rather than a repair.
When Is It a DIY Job?
Sometimes it genuinely is. A small flaking patch on an interior wall at chest height, with a cause you have already identified and fixed, is a reasonable weekend project and there is no reason to pay somebody to do it.
The point where we would tell you to stop is fairly clear.
Stop if the failure is on an exterior above single storey height. Working at height above two metres carries real risk and real obligations under SafeWork NSW, and a ladder on a lawn is how people end up in hospital rather than in a freshly painted house.
Stop if your house was built before 1970, because it very likely has lead based paint in the older coats. Undisturbed, that is generally not a hazard. Dry sanding it into a fine dust that settles in your garden soil, your ceiling cavity and your children play area very much is. AS/NZS 4361.2, the guide to hazardous paint management, covers how lead paint should be managed, and in practice it means wet sanding or dust extraction, containment and correct disposal rather than a random orbital sander and an open window. This is not a scare tactic, it is just the reason that quote from the careful painter is higher than the quote from the fast one.
Stop if the failure is widespread rather than local, because widespread failure means the cause is systemic, and the correct fix is usually a full strip and reinstatement of the coating system rather than a series of patches.
And stop if you have found active moisture and you do not know where it is coming from. That is a diagnostic problem and it is worth an hour of somebody expertise to save you a season of guessing.
A Realistic Example
A homeowner rings us about the exterior of a weatherboard house. The paint is flaking badly under the front windows on one elevation, and nowhere else on the house.
That pattern is the answer. Paint does not fail selectively under windows because the painter got bored at that point. It fails there because water is running down the glass, getting past failed sealant at the sill, soaking into the end grain of the timber below and pushing the coating off from behind.
So the job is not a repaint. The job is to establish whether the sill and the timber below it are still sound, replace anything that has gone soft, reseal the junction properly, let it dry, then take the coating back to a sound edge, feather it, prime the bare timber with the correct primer, seal the end grain, and rebuild the coating.
Then, because the rest of that elevation is eight years older in colour than the repair will be, we would usually recommend recoating the whole elevation to a natural break rather than leaving a visible patch under the windows. On most residential painting jobs that is the difference between a result you notice and a result you do not.
It is a bigger conversation than the one the homeowner expected to have. It is also the difference between fixing it once and fixing it every second summer.
Not Sure What Your Paint Is Telling You?
If you have paint lifting, bubbling or flaking and you are not certain why, we are happy to come and look at it. We will tell you what is actually happening, what is causing it, and whether it is a painting job at all, because sometimes it honestly is not and you deserve to hear that before you spend money.
Every job is quoted after an on site assessment. Every quote is free, there is no obligation, and you will get a straight answer either way.
Call 1300 658 818 or request a free on site assessment. You can also try our painting cost calculator for a rough idea of budget, read our frequently asked questions, or take a look at our work. We paint right across Sydney and greater New South Wales, including the North Shore and the Eastern Suburbs.