EasierVentilation

05 Jun, 2010

Ventilating a house with no roof cavity

Posted by: charles In: Dry your home|Flat roof homes|ventilation no roof cavity homes

Houses with no roof cavity are the hardest to ventilate, they can feel very cold even though the thermometer says it is 21 deg C. These are the homes that really need to be ventilated heated and insulated well.

Ventilating a home with no roof cavity, a flat roof or a skillion roof design is something that should be planned prior to building and should involve a ventilation specialist and the architect who both understand each others point of view and the needs of the client.

There are only two ways to remove moisture from any container (ie your home)
Firstly : the easiest is to get a dry air source – drier than the inside of your home and blow it in, which in turn pushes the dampness out
and dries the container.
The only air source you have is the outside air but it is unfiltered, cold and sometimes equally as damp as your home.
To use this source you need to be very vigilant as to when you open and close your windows and or doors.
If you work away from your home, the problem is you are not at home to make the changes when need be,
If you leave your windows open as we did for many years, your home is no longer as secure.

Secondly: The expensive way, like a kettle, we remove the water (moisture) by heating it up and the water is boiled away and the kettle becomes very dry.
When we heat our homes in NZ we only heat them for 3 to 6 hours a day (depending on where you are) for 4 to 6 mths of the year, unlike England,
Europe or Canada where they heat for 24 hours a day for 8 to 10 mths of the year, and in those places they effectively dry the house out by heating
out the water, yes they have some different ventilation systems but you need somewhere to ‘hide’ or put it (usually in the ceiling).

A home with no roof cavity is very hard to ‘ventilate correctly’ to give you fresh but drier air than what is either inside or outside your home in all seasons.

If you have a space under your floor which can access each room in the house, then I would suggest you investigate a ducted central heating system which will circulate and heat the air in your home but at times can bring in air from outside which can be heated and filtered.
Therefore introducing dryer air in your home and reducing the possibility of condensation.

It is becoming very important that home designers, architect’s and the like, are very aware of the needs of all homes in relationship to Heating, ventilation and insulation as all 3 are equally important as each other and a balance is required in each home, along with using as much free energy as is available at the site of the proposed home.

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