- cooling and heating of re-circulated forced air
- the lack of chimneys
- thermal insulation
- building enclosures that are tight
Thermal insulation causes a building’s enclosure drying potential to reduce. It causes limited flow of air and heat through building assemblies which in turn causes diminished ability of drying when they get wet form exterior or interior sources. This is not a climate based problem.
“Tight” buildings have contributed to an increase in moisture which favours growth of mildew. Buildings have become tighter with each decade causing less efficiency in airflow with an introduction of new chemicals in the interior air. The low rates of air change increase mold potential as well as indoor pollution caused by new chemical products, materials, and compounds.
Lack of chimneys which previously extracted large air quantities from conditioned spaces which in turn resulted in frequent changes in air and the interior pollutants dilution. The elimination of chimneys has contributed to the problems in air quality.
The improvements were meant to conserve energy while making homes more comfortable. Instead, they have contributed to structural deterioration, insurance problems and comfort, health and safety concerns.
There has also been an alteration in construction material to those that encourage rather than deter growth of mold and mildew.
Builders used cedar lath rather and plaster which was too alkaline and deterred growth of mold. Currently builders use drywall that is known for holding in moisture. Plastic pipes which are likely to leak are now used instead of copper or iron pipes. Shower stalls and outer walls can easily leak into wall spaces that are unventilated.
Remediation involves:- correcting service and construction defects
- building monitoring to prevent favourable fungal growth conditions
- reducing or isolating any nutrients that may be available
- reversing favourable fungal growth conditions
