Video - Stain Blocking Primers - Which is Best?

Are all stain-blocking primers made equal?

When dealing with old stains or discoloured surfaces, a standard undercoat often fails to cover problem areas. A dedicated stain-blocking primer is essential. We compared four leading water-based options – Ronseal One Coat Stain Block, Dulux Trade Aqua Uni Primer, Crown Trade PX4 and Zinsser Bulls Eye 1-2-3. Following a light sanding and a single coat application, one primer outperformed the others in terms of opacity and coverage. Watch to discover which product delivers the best base for a flawless topcoat.