Mould growth in water damaged buildings is a well-known problem and has been recognised as having the potential to cause significant health concerns and ongoing damage to building materials if not quickly and effectively addressed. It has always been assumed that the mould spores are sourced from the outdoor air, travel indoors, settle then germinate on building materials once these have absorbed moisture from a leak, or condensation or similar event. However, a recent study
from DTU Systems Biology in Copenhagen, Denmark, has found that gypsum board, irrespective of the manufacturer, leaves the factory with built-in mould spores.
Researchers tested four types of gypsum boards from two different manufacturers, purchased over a six-month period from four different DIY stores in the Copenhagen area – all boards, irrespective of the type, manufacture and DIY store, were infected with the same types of fungus: Neosartorya hiratsukae, Chaetomium globosum and Stachybotrys chartarum. These moulds are common to water damaged buildings, however can be difficult to identify because of their growth habit and colour.
Gypsum board is covered by a layer of recycled cardboard – and it is this layer that can be affected by mould spores during the manufacturing process if the raw recycled material has mould contamination due to being previously wet during storage.
While manufacturers do not advertise their products as sterile, it is reasonable to expect new building products to be safe and healthy at the time they are installed – all supply / install stakeholders have a responsibility to ensure these products meet client expectations.
Moisture is required to germinate mould spores so it is important that all building products, especially gypsum board and similar products with a recycled component are kept dry through out the building process – from supplier, through transport, to on-site storage and installation.
If absorbent building materials become wet during the building process ensure they are quickly and efficiently dried using methods appropriate to the material, that surfaces that have been wet for more than 48hrs are inspected for mould and other biological growth and that any material that shows evidence of mould growth is fully remediated (if possible) or replace.