A lack of subfloor ventilation and internal ventilation causes a moisture build up in the home which results in rising damp and musty odours that can be hard to eradicate.
If the moisture problem is identified as being caused by a lack of ventilation as is often the case, then adding ventilation will obviously assist the building to relieve itself of a build up of moisture.
It is however, very important to understand, that if moisture has established itself in a building, it is often necessary to dry the building prior to establishing or increasing ventilation in the property. A poorly ventilated subfloor is often the cause of rising damp and other moisture issues.
Increasing natural ventilation will sometimes enable a building to breathe enough to reverse an excessive moisture atmosphere - after drying.
In the subfloor, cross flow ventilation is vital and modern building regulations have strict requirements as to the number of passive vents required per lineal metre of wall space. Older properties tend to never have enough passive vents and often even those that are installed are inadequate due to the low level of many older houses. Adding passive vents is a first step to reducing subfloor moisture - and Dampco can install passive vents (subject to access) from as little as $290 per vent.
If moisture and damp is an ongoing problem, the best method of permanently relieving the property of a build up of moisture in either in the subfloor or roof cavity is to add a mechanical (forced air) ventilation system.
Forced air ventilation systems are controlled by a 24 hour timer or a hygrometer (humidity thermostat) automating the process of on going ventilation. Because they are powered (not solar) and switched, these systems put the home or building owner in complete control of their indoor environment and they are therefore able to manipulate the indoor ventilation to permanently keep the property moisture free.
Drying the property prior to installing a forced air ventilation system is generally required.
If a lack of subfloor ventilation is causing an ongoing rising damp problem, the best method of resolving the build up of moisture in the property is to use a forced air ventilation system. These are typically switched via a 24 hour timer or a hygrometer (humidity thermostat) and are operated via 240V.
Again, it must be stressed that drying the property before installing a forced air ventilation system is recommended.