Stain block
Jump to navigation
Jump to search
Stains on emulsion paintwork often bleed through when painted over, and repeated coats of emulsion fail to block them. A coat of any of the following can stop this happening:
- dilute PVA
- Oil based (alkyd) non-gloss paint, such as undercoat or eggshell
- Stain block paint
- Shellac
Usually one coat is enough, but not always. The very worst stains can require alternating coats of emulsion and oil paint of stain block. Since oil paint is slow drying, stain block is then preferable.
Fire
Staining of walls following a fire is a bit different to water staining, and aluminium primer is favoured. This forms a layer of aluminium flakes, blocking soluble staining and odour.