Large scale fungal contamination
Our next client was currently developing a four storey apartment block when work came to a halt due to evidence of fungal contamination being found. We were called in to evaluate the indoor air quality in the complete, affected apartment and to identify the root cause of the fungal contamination. We were also instructed to carry out an inspection to the plot still currently under construction.
Inspecting the completed apartment
Our surveyor inspected the apartment thoroughly for evidence of elevated moisture levels in construction materials. All the plasterboard ceilings and walls revealed consistent and uniform levels of relative moisture. However the material relative moisture levels were low and below levels that support fungal growth. All the wooden skirting boards and furnishings within the apartment also revealed uniform and consistent moisture levels but at low levels that would not support fungal growth.
The ventilation in the bathroom is provided by a ceiling mounted extraction fan. We measured the air velocity of the extraction fan with the decorative cover removed and based on our measurement the calculated extraction rate of the bathroom fan was below the recommended rate. From this we can assume that the decorative cover would further reduce the extraction rate due to air flow resistance, further decreasing the expected extraction capacity of the system. Our surveyor then inspected the external areas which showed that weeping vents in close proximity to the entrance door had been covered with a decorative lining.
We concluded that the existing ventilation in the apartment is not sufficient in controlling internal humidity levels under normal living conditions. Therefore we recommend that the extraction capacity of the installed ventilation system is reviewed and increased in accordance with the relevant building regulation requirements.
Inspecting the unfinished plot
Our surveyor then inspected the unfinished plot where he identified several areas of leaks and damp construction materials. Standing water was also observed in the lift shaft of the property. The building was only partially weather tight however small leaks from between the concrete floor plates were observed in a large number of rooms. The screed which had been applied to the block walls was still saturated with water and in a large number of places was stained from water leaks. Several areas of damp block walls were identified and the level of dampness was much greater than the surrounding wall which suggested active water penetration.
Our surveyor concluded that the root cause of the existing mould contamination to the plasterboard was water condensation from the ambient air. A combination of numerous small water leaks, several places of water saturated block walls and floors, standing water, wet wall screed and a reduced rate of ventilation resulted in conditions of high ambient humidity and subsequent fungal growth. We strongly recommended that all the building materials were sufficiently dried before the installation of plasterboard panelling.