There are many websites advising all houses should have ventilation in the roof space. Most of these sites are American or European and much of the information is of little value here in New Zealand. However, the one common theme that is relevant in NZ is that every house DOES need adequate ventilation into the roof/ceiling space.
Over the years the building code has changed – originally every house needed ventilation and older homes have lots of natural vents. Tiled roofs for example naturally vent around the tiles. Some time ago it was decided that the roof ventilation was the cause of lost heating so the code was changed to seal the roof space. This caused many problems. In 2014 the building code changed again to require adequate roof ventilation.
It has been proved that a well-insulated ceiling in a modern home does not loose significant heat as a result of roof ventilation. The advantages of ventilation are many and there is almost universal acceptance that every roof should have ventilation.
As a result, a number of companies are manufacturing proprietary products that provide for the building code requirements. Unovent has become aware of the Blue Building Solutions (BBS) website which is well worth a visit - http://bluebuildingsolutions.co.nz/
On the occasions a customer contacts Unovent saying that their recently installed Unovent Ventilation isn’t solving the home dampness problem, we make every effort to discover why. If air is being emitted from the fans in each room then the problem isn’t the Unovent system. Most suspect this is just a cop-out. The reality is that Ventilation systems are all doing the same task – moving air from the roof space into the rooms below. If the rooms below are not drying out, then the problem is very likely the air being moved is damp (there can be other problems – but start by checking the roof ventilation).
Damp air in the roof space almost always results from inadequate ventilation from the outside. We are surprised to discover the number of homes that have totally sealed roof spaces. It’s very difficult to tell a customer there is a problem with their home. It’s the last thing they wish to hear … and often they think it will be a large expense to remedy. Happily, it need not be expensive and in many instances it will not cost a cent. One of the faults we have discovered is the insulation has been packed into the edge of the ceiling and blocked the soffit ventilation path. Easily fixed for free.
If your home was built between 2002 and 2014 it may be worth checking if the roof space is (incorrectly) fully sealed – or does have adequate ventilation.