jeff posted on February 01, 2010 06:09
As the part L regulations place increasing emphasis on heat and air leakage the development of indoor air quality problems and specifically “Toxic mould” increases. Warm buildings without adequate ventilation result in condensation forming on surfaces adjacent to the insulation. Several questions need to be answered to provide a logical explanation.
Toxic mould is ubiquitous and has been around planet earth for millions of years, it usually only develops in forests where it devours dead cellulose materials such as dead trees and vegetation. Its spores are everywhere but needs specific growth conditions. It usually is harmless to humans but when challenged for food or under attack (drying out or desiccation) or being killed by the application of biocides (bleach) it releases mycotoxins which are extremely hazardous and indeed the US military have developed T” toxin as a chemical weapon directly from mould.
Water activates the viable spore into growth and moisture is present from leaks due to poor building envelope, where vapour retarders, drainage plain has gaps and a dozen other construction or design problems. Equally and especially with reference to part L lack of adequate ventilation means moisture build from life style and resultant condensation. It should be recognised that a family of 4 can produce 15 litres of water a day from cooking, breathing and showering.
The mould spore is always present in the air, moisture build is increasingly a problem with tight buildings and the missing part of the equation is food. Cellulose materials such as wood and paper are ideal nutriment for mould and considering our new buildings are usually built with plasterboard which can absorb and hold the moisture and is covered in paper (cellulose) we have ideal growth conditions especially in cavities where conditions are similar to a mushroom (fungi) farm, no light, moist and warm.
All mould is allergenic but some are considered toxic because of their serious health effects which include:
- Flu like symptoms
- Lung & liver cancer
- Brain tumour
- Depression
- Spontaneous abortion
- Depression etc. etc
Although there are tens of thousands of different moulds, only 16 have been identified as toxic. These toxic moulds unfortunately have been identified because they are generally found in buildings, ventilation systems, cavities and surfaces usually corners or behind obstructions where air flow is limited.
Builders, occupants and architects and even compliance to legislative requirements may be responsible to varying degrees but identifying the main causes of decay, damp, condensation, mould and accepting occupants health concerns should be a first step. Building Forensics have developed many unique survey and inspection techniques to assess and identify building defect and or design and combine life style conditions to assist in the identification of fault and potential remediation.