Nicotine, old water stains and tannin from certain timbers all contain compounds that dissolve back into standard water-based paint and bleed straight through, sometimes within days of a repaint. A dedicated stain-blocking primer isolates the mark before it ever gets the chance.
Usually not — standard primer allows the stain to migrate through repeatedly. A dedicated stain-blocking primer isolates it chemically rather than simply covering it with more layers.
A light clean and dry is normally enough for most stains; heavy nicotine residue may need washing down first so the primer bonds to a clean surface.
Most are compatible with standard water-based emulsions and gloss once cured, but we check the specific product's recoat guidance before proceeding.
Ordinary emulsion is water-based, and many stains are water-soluble or oil-soluble in ways that reactivate under a fresh water-based coat. The mark migrates upward through the new film as it dries, showing as a faint yellow or brown shadow exactly where it was before.
Nicotine and smoke residue, water and tannin staining each respond best to slightly different blocking primers, some solvent-based, some water-based shellac or acrylic hybrids. Using the wrong type can mean the stain still finds its way through.
Stain blockers need full, even coverage over the whole affected area and a margin beyond it, not just a dab on the darkest spot. Missing the edge of a stain is the most common reason it reappears in a thin ghost line weeks later.
Send a photo of the stain and we will confirm which blocking primer will actually hold it back.
Stain blocking works by chemical isolation, not extra coats, and matching the primer to the stain type is what makes it hold.
Speak to a Hampshire commercial decorating contractor that turns up, communicates clearly and delivers a finish that lasts.
