A sheltered inland courtyard wall might go fifteen years and still look reasonable. A south-facing seafront elevation at Punta Prima might be visibly tired in four. Both are normal.
What actually determines the interval
Which way it faces. South and west elevations take several times the UV load of north elevations. On most properties you'll see one face fail well ahead of the others.
How close you are to the sea. Salt exposure drops off with distance, but not as fast as people expect. A front-line property is on a materially shorter cycle than one a kilometre inland.
What was used last time. A good siloxane coating properly applied over prepared render will comfortably outlast a cheap acrylic sprayed onto a dusty wall.
Colour. Deep and saturated colours — particularly reds, oranges and dark blues — fade faster under strong UV than pale ones. Terracotta and ochre tones are traditional here partly because they weather gracefully.
Whether it was prepared properly. By far the biggest single variable, and the one you can't see from the road.
Six signs it's due
- Chalking. Rub your hand firmly across the render. If it comes away with white or coloured powder on it, the binder has broken down. This is the clearest single indicator.
- Uneven fade between elevations. When the south wall is visibly a different shade to the north wall, the coating is failing rather than the colour simply mellowing.
- Fine crazing. A network of hairline cracks across the surface. Not usually structural, but it lets water in behind the coating, and once water is in, failure accelerates.
- Flaking or blistering. Any area where the coating has lifted. This never improves on its own and always spreads.
- Green or black staining on sheltered and north-facing walls. Algae and mould. Cosmetic at first, but it holds moisture against the surface.
- Rust staining running down the render from a gate hinge, grille fixing or balustrade. The metalwork is the actual problem, and it's staining the wall as a side effect. See painting metal gates, grilles and railings.
Doing one elevation at a time
Perfectly reasonable, and often the sensible way to spread the cost — do the south and west faces now, the sheltered ones in a few years.
The thing to be aware of is that they won't match afterwards, and the difference is more obvious than most people expect. On a prominent frontage it's usually worth doing the whole thing.
Leaving it too long
There's a point where a repaint stops being a repaint. If the coating has been failing for years, the layers underneath have usually lost their grip too — and at that stage sections need taking back rather than painting over.
That's a considerably bigger job. Catching it at the chalking stage rather than the flaking stage is the difference.
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