Rising Damp
First the source of the damp must be fixed: DampStop + HydroFix for rising damp, or repairing the point of entry (roof, terrace, façade, plumbing) where water gets in. Then let the wall dry; drying time depends on the season and how deep the wetness goes. On surfaces treated with HydroFix, wait at least 3 days and until the plaster is visibly dry before painting.
Repair sequence: scrape off bubbling paint and loose plaster; brush off salt marks dry (for heavy salt, D201 salt converter). Level the surface with R102 thin repair mortar. Apply a stain-blocking primer to remaining water marks and finish with a breathable (vapour-open) paint. Plastic or oil-based paint and vinyl wallpaper trap moisture and are not recommended. Paint applied to a wet wall soon bubbles again. For ceiling and upper-floor stains see upper floor, ceiling and window damp.
Repair sequence: scrape off bubbling paint and loose plaster; brush off salt marks dry (for heavy salt, D201 salt converter). Level the surface with R102 thin repair mortar. Apply a stain-blocking primer to remaining water marks and finish with a breathable (vapour-open) paint. Plastic or oil-based paint and vinyl wallpaper trap moisture and are not recommended. Paint applied to a wet wall soon bubbles again. For ceiling and upper-floor stains see upper floor, ceiling and window damp.