Sub-Floor Ventilation

Many buildings in Australia have suspended flooring with an accessible sub-floor.

The sub-floor area is often enclosed, damp and poorly ventilated providing an undesirable environment that is conducive to mould growth, termite activity and decay.

Correct sub-floor ventilation reduces the risk of these factors and to a degree improves the quality of living within the dwelling. Important to note, ventilation improves conditions by sweeping of some suspended humidity and providing for a drying effect, Ventilation does not deal with the source of the moisture that we are trying to remove through ventilation or moisturte being dried off.

In general terms sub-floor ventilation is divided into two forms, natural cross flow ventilation and mechanical ventilation.

We have expertise in creating the most desirable ventilation for the type of building considering the buildings physical location.

To create good sub-floor ventilation we need to consider the exposure of a particular building to prevailing winds, the overall size of all the openings in relation to the void that needs to be ventilated and that ventilation openings correctly correspond with openings on the far side of the void to be ventilated.

It can also be very important to have correct (or controlled) ventilation at certain times of day or alternatively under certain weather conditions. Many will consider installing mechanical ventilators that work during periods when the weather outside is warm and humid as is often the case in the middle of the day, therefore actually introducing higher humidity into a void and causing poorer conditions within the sub-floor and the interior of the building.

When considering sub-floor ventilation it is important to consider natures physics. Hot air will absorb larger amounts of humidity and tends to rise while cold air will compress and therefore reduce the amount of humidity and stay drier. In understanding this simple fact, we can design our ventilation to suit particular conditions and use nature to assist in providing us with the most advanced ventilation. This is an area that our expertise on the subject of ventilation has been so successful, in many cases we will adapt the forces of nature to provide us with a superior ventilation system.

In recent years I have had trouble understanding one of the most popular sub-floor ventilation systems on the market simply due to the fact that it goes against all physical theory of preferred sub-floor ventilation. The solar fan concept has had me scratching my head over time as to why this system should provide beneficial ventilation. It is powered by solar panels that are charged during daylight hours by the suns rays, therefore it is often working when the conditions are warmer and therefore the ability of the air to absorb moisture is greatest. Sadly, without prejudice to the manufacturers or marketers of these products, I have personally observed on numerous occasions, while inspecting buildings, that these systems have in some instances actually contributed to a higher level of humidity under a building rather than the desired affect of reducing the humidity.  Having said this - we still encourage some type of ventilation rather than no ventilation at all.

I will not provide you with all my trade secrets on this page as it is still important for me to continue to make a living from the knowledge I have gained over time.

It is often not enough just to provide ventilation under a building and this is where we have found the concept of Sub-floor Solutions so effective as we also alter the environment under the building together with the installation of additional sub-floor ventilation.

The information on this page is generally brief and only explains a very small part of the overall complexities related to correct sub-floor ventilation.

For further information please contact Stephen Koelewyn

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Not a Member of AEPMA Association.

Stephen Koelewyn - NSW Builders Licence 45109c - Building Consultant Licence BC213 (Now Obsolete in NSW) - Pest Control Licence - NSW 15-001467-004

I would love to hear from you. Call Steve

Last modified: 2 August, 2022->->->