Water-Based or Oil-Based Paint?

Water-based paints (sometimes labelled 'acrylic' or 'quick-drying') use water to carry the paint. Oil-based or solvent-based paints use white spirit or similar solvents. That difference affects how they go on, how fast they dry, how they smell and how they age.

Almost all wall emulsions are water-based. The real debate is about woodwork, metal and some exterior surfaces.

Water-based trim paints dry quickly – often recoatable the same day – so a room can be finished faster. They have much less smell, which matters if you're living in the house while it's being painted. And they stay white, whereas oil-based whites tend to yellow over time, especially in rooms with little daylight.

Oil-based paints flow out beautifully, leaving fewer brush marks and a very hard, smooth finish. Some decorators still prefer them for front doors, high-wear joinery and when painting over existing oil-based gloss. They can also be more forgiving in cooler conditions.

The downsides are the long drying times – often overnight between coats – the strong smell and the yellowing. Some products have been reformulated over the years to cut solvent content, so performance varies.

Yes, but not by simply painting over the top. Water-based paint won't grip well on shiny old gloss. The surface needs cleaning, sanding to a dull finish and usually a suitable primer or undercoat. Skipping this step is a common reason for paint peeling off skirting boards.