Painting Contracts · Question

What does a painting contractor do about cracks and uneven plaster before painting?

Short answer

A careful contractor first inspects the walls, then separates cracks into surface hairlines and deeper or moving ones. Hairline cracks are usually opened, filled and smoothed, hollow or loose plaster is cut out and patched, and uneven areas are levelled with putty before primer. Cracks that keep growing point to a structural or moisture cause and need a professional opinion.

In more detail

Paint hides nothing that is underneath it. Any repair left out of the scope appears in the finish, and in a few months the cracks come back through the paint. So the quality of the repair stage decides the quality of the final wall.

The usual sequence on a wall with defects runs like this. The contractor checks the surface, tapping to find hollow plaster, and notes patches of damp, flaking old paint and salts. Loose and flaking material is removed back to a sound edge. Cracks are cleaned out, and suitable filler or crack-bridging material is applied, often with reinforcing tape or mesh across joints between different materials such as brick and concrete. Hollow plaster is cut out and patched to match the level. The wall is then sanded, dusted down, puttied where needed and primed.

What the scope should say:

Whether crack filling and minor plaster patching are included, and up to what extent, in words such as minor or major, defined by the parties.
Who pays for large areas of replastering, and how they will be measured.
Whether paint removal and re-priming of peeling surfaces is included.
How cracks that reappear are handled during any defect period.

Not every crack is cosmetic

Wide cracks, cracks that grow, stepped cracks or those with leaking or bulging beside them may signal movement, settlement or water entry. A painter should not simply fill them. Ask a structural or building professional to look, and carry out any needed repair first.

Expect the contractor to point out such problems before starting, and to price the repairs separately. A quote that treats a heavily cracked wall like a clean one is a signal that preparation will be skimped.

Key points

Hidden defects show through paint, so repair comes before putty and primer.
Hairline cracks are opened, filled and smoothed; hollow plaster is cut out and patched.
Reinforcement is often used where different materials meet.
Write the extent of crack and plaster repairs into the scope and measurement basis.
Growing or wide cracks need a professional opinion, not only filler.

Who this applies to

Owners of older buildings with visible cracks and rough plaster.
Landlords repainting units after years of use.
Managers drafting a painting scope for a building with uneven walls.

Last reviewed 3 October 2026

This answer is general information, not advice on your particular case. Terms, eligibility, and requirements change, so check the current position with the relevant institution or authority.