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ABSTRACT:

Use of a 'breathable' silicate paint without a silicate primer on 9mm Magnesium Oxide weatherboard cladding:  A Case study in Canterbury, New Zealand

Due to recent efforts to lower the carbon footprint and increase the sustainability of residential and commercial building methods, there has been a shift to new “greener” products for which there is limited experience under NZ climatic conditions. One such product is Magnesium oxide MgO panels which have been heralded for lower CO2 during the production phase as well as atmospheric carbon sequestration during the life of the product, resulting in an estimated 20-40 percent reduction in carbon emissions compared to traditional cement boards. As a result of these new products, coating systems have been applied in which a trusted product is used on a new substrate. One such product is a silicate-based paint, popular in Europe for use on mineral substrates, such as cement, stone and lime. This paper describes a case study in which the builder and the painter used the combination of a silicate-based paint (without a separate primer or binder) on a Magnesium oxide board in a dark colour according to the supplier’s system (for both substrate and paint) recommendations.

BIOGRAPHY:

I am a SCANZ member and New Zealander of Dutch-American extraction. Prior to and during my university studies university I worked in the building industry, having come from an “engineering” family with roots in construction, plumbing and heating.

Education - Vanderbilt University (Nashville) BSc degree in Chemistry. Texas A&M University (College Station) MSc, Postgraduate veterinary training at University of Florida (Gainesville) following graduation in The Netherlands (Utrecht University) DVM.  

Currently Researcher and PhD candidate, employed by The University of Otago, Christchurch, Dept. of surgery. Co-author of 15+ scientific articles and scientific reviewer. I am a medical scientist working on colorectal cancer. I have a keen interest in how environmental factors including volatile compounds from paints and adhesives influence human health. In addition to talks presented at veterinary or medical conferences, I have been an invited speaker to The Viva Project “Otautahi” (Christchurch) and Lincoln Envirotown (Selwyn) on experiences with sustainable building. As a home owner/designer.

This presentation is a case study from a single residential home built in 2019, documenting cladding problem in the Canterbury climate associated with the use of a silicate-based paint, normally used for cement or stone surfaces, but approved by Beal for 9mm Magnesium oxide/chloride weatherboard cladding. The presentation will include analyses by building experts and certified laboratories in the determination of the failure of the cladding to meet NZ standards.