Damp, condensation & ventilation
Damp and condensation both lead to mould. They can damage your building or worse your health. Damp can be caused by a number of things: a leaky drain, pipe, roof, rising damp due to a lack of a damp proof membrane, but to name a few reasons. It’s important to get to the route of the damp problem and address it appropriately.
Condensation can be a more complex issue to solve. It is caused by an increase in internal humidity, and is often attributed to people breathing, cooking, bathing and drying clothes. In order to reduce the effects of condensation, the control of moisture is necessary along with appropriate insulation, heating and ventilation. Moisture will condense on a cold surface, so therefore we try to insulate walls, ceilings, floors and of course install good glazing to increase internal surface temperature and reduce the risk of condensation.
With insulation, Its important to note that certain methods and using certain thickness of dry-lining have been found to move this condensation issue into the wall structure, effectively hiding but not dealing with the problem.
The need for heating is self-explanatory in that, it’s important especially with old buildings that some background heating is used regularly.
Permanent background ventilation is required by law in all habitable rooms. This can take several forms including the usual ‘whole in the wall’ vents, window vents and several types of mechanical ventilation. It’s becoming clear that with increased air-tightness there are questions and decisions to be made regarding how we supply adequate fresh air to our new and retro-fitted homes. In retrofit situations with increased air-tightness and insulation levels the use of mechanical ventilation can often be the best solution –although specialist assistance in choosing a system is recommended.
Mechanical Heat Recovery Ventilation (MVHR) is a relatively new phenomenon in Ireland but well established in other countries. Its main bonus as the name suggests, is it systems ability to re-cycle your homes generated heat while, providing fresh external air in the process. These systems are not that suitable for retro-fit scenarios, unless an amazing standard of air-tightness is achieved.
The use of a humidity stat can help to ascertain whether your home may have a condensation or damp problem. A normal house should read between 40 -70% relative humidity (RH) on a typical sensor (allowing for some cooking, washing fluctuations here), you’ll get one online for circa €30. If you feel you have a damp issue, a good initial inspection can be carried out by simply using your hand or with the aid of a damp meter – a cheap one will be available online for circa €20