Resene Paints - home page


From the Resene paint and decorating problems solver

Efflorescence is the term used to describe crystalline (or powdery) deposits, usually white in colour, that sometimes form on the surface of brickwork, concrete plasters and other concrete type structures.

In most cases efflorescence is the result of calcium hydroxide (lime) from cementitious substrates being carried to the surface by water. This then reacts with carbon dioxide in the air to form insoluble calcium carbonate. Normally efflorescence is only of cosmetic concern although it can ruin the appearance and physically damage paint coatings.

Efflorescence is most often the result of uncontrolled moisture movement caused initially by poor design details and poor construction techniques. Before attempting to remove efflorescence the source of moisture getting into the substrate should be eliminated.


  • Joints and cavities are properly sealed;
  • Rainwater run-off is diverted to suitable drainage;
  • Physical barriers are in place between brickwork and in situ concrete;
  • Tops of parapets have cappings and windows and doors have suitable flashings in place;
  • Cavities are well-ventilated;
  • Vapour barriers are used to stop uptake of groundwater.

Efflorescence can be removed by physically scrubbing with a stiff brush and careful washing. Waterblasting may result in a continuation of the efflorescence as more water may be blasted into the substrate.


Resene Paint and Decorating Problems Solver
Learn more about typical painting problems and situations you may find when decorating. Also, understanding paint hazards and essential precautions - putting your safety first!

Problem solver topics   Safety topics   Ask an Expert

Resene Paints Ltd

Resene Paints Ltd   –

We would love to hear from you if you wish to use Resene's images, information and ideas for social medial, blogs, newsletters and other media use. Please email and let us know what you need, what it is for and how Resene will be acknowledged as the source of the content. We are happy to assist with most requests.

Our vision is to be respected as a trusted, ethical and sustainable company and acknowledged as the leading provider of innovative paint and colour technology. View Resene’s profile, Quality Policy, Environmental Policy and Health & Safety Policy.

Any personal data, such as name, address, phone, email details, supplied to Resene for the purposes of receiving newsletters, orders etc will be retained by Resene Paints Ltd and used only by Resene Paints Ltd and its trusted agencies for the purposes of communication/promotion/providing service to you. We do not sell, trade or otherwise transfer your personal data to outside third parties. If you wish to opt out of communication from Resene please complete our contact us form. View our full Privacy Policy.

Colours shown on this website are a representation only. Please refer to the actual paint or product sample. Resene colour charts, testpots and samples are available for ordering online.   See measurements/conversions for more details on how electronic colour values are achieved.

View Videos