Earth construction – bubbling or blistering surface finish

Cause

Loss of adhesion due to excess moisture in substrate

Repair

  • if blistering goes through to the substrate, it indicates that there is a high moisture content in the plaster and this must be addressed before repainting
  • scrape and/or sand off loose paint; clean until surface is sound; allow to dry thoroughly; prime; fill joints with exterior grade flexible (polyester) filler; paint with a minimum two coats of semi-gloss or high gloss acrylic paint suitable for the plaster finish

Cause

Poor initial substrate preparation

Repair

  • if blistering goes through to the substrate, it indicates that there is a high moisture content in the plaster and this must be addressed before repainting
  • scrape and/or sand off loose paint; clean until surface is sound; allow to dry thoroughly; prime; fill joints with exterior grade flexible (polyester) filler; paint with a minimum two coats of semi-gloss or high gloss acrylic paint suitable for the plaster finish

Cause

Oil-based (alkyd) paint applied over water-based (latex) paint

Repair

  • if blistering goes through to the substrate, it indicates that there is a high moisture content in the plaster and this must be addressed before repainting
  • scrape and/or sand off loose paint; clean until surface is sound; allow to dry thoroughly; prime; fill joints with exterior grade flexible (polyester) filler; paint with a minimum two coats of semi-gloss or high gloss acrylic paint suitable for the plaster finish

Cause

Surface was damp or dirty when painted previously

Repair

  • if blistering goes through to the substrate, it indicates that there is a high moisture content in the plaster and this must be addressed before repainting
  • scrape and/or sand off loose paint; clean until surface is sound; allow to dry thoroughly; prime; fill joints with exterior grade flexible (polyester) filler; paint with a minimum two coats of semi-gloss or high gloss acrylic paint suitable for the plaster finish

Cause

Dark colours increasing surface temperatures

Repair

  • if blistering goes through to the substrate, it indicates that there is a high moisture content in the plaster and this must be addressed before repainting
  • scrape and/or sand off loose paint; clean until surface is sound; allow to dry thoroughly; prime; fill joints with exterior grade flexible (polyester) filler; paint with a minimum two coats of semi-gloss or high gloss acrylic paint suitable for the plaster finish

Cause

Water-based paint coat exposed to moisture before paint has fully dried

Repair

  • if blistering goes through to the substrate, it indicates that there is a high moisture content in the plaster and this must be addressed before repainting
  • scrape and/or sand off loose paint; clean until surface is sound; allow to dry thoroughly; prime; fill joints with exterior grade flexible (polyester) filler; paint with a minimum two coats of semi-gloss or high gloss acrylic paint suitable for the plaster finish