Painting or plastering: when each one is needed

Paint changes the surface, not the shape of the wall. A coat of paint evens out colour differences, refreshes the look and protects the surface, but it doesn't level unevenness, fix deep cracks, or hold together loose old plaster. If the wall underneath is in good condition, painting alone is entirely sufficient.

Plastering and skimming work address a step earlier: they create a flat, sound surface before paint even comes into play. If a wall needs structural correction, there's no way around this work — an extra coat won't solve it, only hide it briefly.

A good coat of paint refreshes the look, evens out minor colour differences from earlier patchwork, bridges fine hairline cracks with flexible paint systems, and protects the surface from dirt. For most flat renovations where the wall is fundamentally sound, that's all that's needed.

What paint can't do: it won't fill deep holes, won't cover larger cracks permanently, won't flatten an uneven surface, and it doesn't hold reliably over poorly bonded old paint or over glue paint. If you paint over these anyway, the flaws usually reappear within a few months — the crack opens up again, and the paint peels wherever the surface underneath wasn't sound.

Plastering and skimming even out unevenness, close holes and cracks permanently, and create a smooth surface with consistent absorbency. It's the right step when a wall has structural flaws, when old wallpaper has been removed and the surface underneath is uneven, or when a room needs a higher surface quality — for example before a dark or glossy paint finish, which shows every imperfection.

Extensive cracking, broken-out corners, a large number of old wall-plug holes, or switching from wallpaper to painted walls also fall into this category. After plastering, priming usually follows, and only then the actual paint coats.

One simple test often tells you a lot: hold a lamp at a shallow angle close to the wall (a raking-light test). This reveals unevenness, waviness and old patch repairs that are invisible under normal lighting. If the test shows lots of shadows and irregularities, that points to a need for plastering.

With cracks, the distinction between hairline and structural cracks matters most. Fine, surface-level hairline cracks you can barely feel with a fingernail are usually harmless. Cracks that visibly open up, run across several storeys or through corners, or change with the seasons should be checked and generally plastered — or assessed by a professional.

There's a simple test for glue paint too: rub a damp cloth or finger over the wall — if the paint chalks off heavily and sticks to the cloth, it's very likely old glue paint, which shouldn't be painted over directly. In the trade, surface quality is also often graded in Q-levels (Q1 to Q4): Q1 is a basic surface without skimming, while Q3 and Q4 describe very smooth, high-quality finishes needed for things like dark wall colours or finely textured wallpaper.

In practice, painting and plastering rarely compete — they follow each other. A typical sequence is: patch small holes and cracks, skim larger areas where needed, sand, prime, and only then apply the top coats. Skip a step — for example painting straight after plastering without priming — and you get patchy, uneven results, because freshly skimmed material absorbs paint differently than the rest of the wall.

Switching from wallpaper to painted walls, or changing paint systems (for example from old glue paint to modern dispersion paint), almost always requires preparatory work too, regardless of how the wall looks at first glance.

Whether a wall just needs painting or also needs plastering changes both the time required and the order of the work. That's why checking the surface at the site visit isn't a formality — it's the basis of the quote: it determines whether a plastering line item is needed at all, and how much of it.

If the true condition of a wall only becomes visible during the work — for example when removing wallpaper reveals bigger damage underneath — that's a legitimate reason to adjust the quote. A serious contractor discusses this with you before doing the extra work, rather than simply adding it to the final invoice.