Written answer by MND on anti-mould paint for HDB flat exterior walls for flats built near humidity sinks

Feb 7, 2023

Questions by: Mr Don Wee Boon Hong and Assoc Prof Dr Jamus Jerome Lim

*4085. Mr Don Wee Boon Hong: To ask the Minister for National Development (a) whether anti-mould paint is a standard feature for HDB flat exteriors especially for flats built near humidity sinks, such as rivers, forested areas, reservoirs and sea fronts; (b) what rectifications are available for flats that face premature growth of mould; and (c) whether the Ministry will revise the Singapore Standard SS345 on specification for algae resistant emulsion paint for decorative purposes.

*4170. Assoc Prof Dr Jamus Jerome Lim: To ask the Minister for National Development whether HDB has considered specifying even higher-grade weather resistant finishes, beyond the existing SS345 algae-resistant paint and SS500 elastomeric wall coatings, to account for varying project conditions, for example for seafront or riverfront housing estates.


Mr Speaker, may I have your permission to answer Questions 4085 and 4170, filed by Mr Don Wee and Assoc Prof Dr Jamus Lim?

2        To rectify mould growth on external walls, thorough cleaning and patching of cracks are conducted, before repainting the walls with sealer and algae-resistant paint. This is usually carried out by Town Councils as part of their management and maintenance of the common property.

3        The external walls of all HDB developments are painted with 1 coat of water-based sealer and 2 coats of algae-resistant emulsion paint. The water-based sealer enables better paint adhesion to the surface and is commonly used on external walls before the application of algae-resistant emulsion paint. The algae-resistant paint contains biocide which prohibits the growth of algae culture and gives the paint its algae resistant properties. The sealer and emulsion paint used in HDB blocks complies with the Singapore Standard 579 and the Singapore Standard 345 respectively, and they are also commonly used for buildings in Singapore, for both public and private sector projects.

4        These standards, which have helped ensure that external façade walls remain clean and clear of mould over the last 20 years, were most recently reviewed with industry experts in 2021 to ensure that the standards are updated and remain relevant to the industry. These standards were also used in numerous other HDB projects, where no such incidents of mould growth have been identified, including developments located near waterbodies.

5        HDB is currently commissioning a technical assessment to determine the cause of mould growth at Anchorvale Parkview and Matilda Court. Depending on the outcome of this assessment, the Singapore Standards Council will assess the need to further review the relevant standards, on top of the periodic review carried out every five to eight years to ensure their relevance.