Priming before painting

Primer is the layer nobody sees after a renovation, yet it decides whether the paint grips the wall and covers evenly. Priming before painting evens out how absorbent the surface is, binds dust and strengthens weak plaster. Without it, paint soaks in patchily and can start peeling within months.

When priming is essential

• on fresh filler and gypsum plaster, which draw water out of paint fast;
• on plasterboard, where the paper face and the joints absorb differently;
• on old, dusty or chalky walls;
• when switching from a dark colour to a light one or vice versa, using a tinted primer.

A wall already painted with good, well-bonded paint does not always need primer. The handyman checks with a simple test: pressing tape on to see if it lifts the paint, or running a hand over the wall.

Types of primer

Deep-penetrating primer strengthens weak, dusty surfaces. Bonding primer improves adhesion on smooth surfaces. Pigmented undercoat evens out the colour and often saves one topcoat. The handyman chooses the type for the wall and the paint you picked, because some manufacturers specify a particular primer for their paints.

How priming is done

The surface is dusted, dents are filled, and then the primer goes on by roller or brush, evenly and without runs. It has to dry before painting, usually a few hours according to the data sheet. In a whole flat, the handyman primes one room while preparing the next.

Common questions