All homes need roof ventilation due to excessive thermal overload to the roofspace and the over insulation of today’s homes.
Concrete roof tiles absorb massive amounts of summer heat likewise with terracotta tiles and colorbond – this excessive heat is transferred to the roofspace causing thermal overload. It can be up to 75°C during the summer months in the roofspace. With this heat being trapped between the ceiling insulation and the roof covering. After 5 days of this excessive heat ceiling insulation loses its integrity and the thermal overload permeates the insulation radiating down into the living areas.
Have you often wondered that you have all the windows open in the evening and there is a nice crossflow breeze happening, you still can’t sleep, why? Because the thermal overload in the roofspace is radiating into your living areas long after the sun goes down.
That’s not the only problem that can happen in the summer months, this thermal overload can wreak havoc and can cause damage to the building materials, see Blog on this site “Thermal Creep”.
WHY DO I NEED ROOF VENTILATION IN WINTER
It’s adviseable to have roof ventilation for all 4 seasons, in winter due to escaped heat from the home into the roofspace can be as much as 25% this can be from several areas – heat rising from inside the home. As well as heat loss from ceiling protrusions such as fans dumping into the roofspace, around downlights and any electrical or plumbing fittings that protrudes the ceiling. When this heat hits the underside of the roof covering the moisture in the heated air condensates and turns to water, it could be raining in your roof. Suggest you read this Blog “Warning! Read Before You Design Your Next Housing Project”. This Blog will explain the damage that can happen due to over insulation and condensation damage.
The other benefits of roof ventilation are for a cooler home in summer and a drier roofspace all year round. So the answer to why do I need ventilation is for a cooler home in summer, a drier roofspace 24/7 and a healthier roofspace to alleviate all the nasties of the roofspace.