Roof ventilation is almost always necessary in all buildings. To understand why, it is important to appreciate the purpose of ventilation in the roof and the building as a whole. They facilitate the free flow of air between the interior of the house and the external environment through an intake and an exhaust.
The roof ventilation helps in regulating the temperature of the building but it also lets in fresh and dry air into the house while pushing out warm air in the building to the external environment. This circulation often means there is very low difference between the conditions in the house and those outside the house. This will have several advantages for your structure and the comfort of the house as a whole.
For ventilation to work in your building there must be regular air flow. The flow of air in the attic which facilitates good ventilation can be achieved naturally or through a mechanical process such as through HVAC systems.
Mechanical ventilation is costlier since you must invest in some form of air conditioning equipment which will involve the expenditure of energy. On the other hand, you can have natural ventilation that is incorporated in the design of the roof. In natural ventilation, the forces of convection will work to pump out hot air out of the building and bring in cool air.
While natural ventilation is good, it is not efficient so it will not circulate a sufficient amount of air that will provide you with optimal ventilation. Mechanical ventilation can move a good amount of air but it can be costly and might not be as efficient during all seasons. The middle way is to install roof vents while working around the house to minimize the gaps in insulation. Most builders recommend this “third way” and it can be achieved right from the beginning during the design of the building. Insulation and ventilation can also be incorporated in an already existing building.
Why Your House Needs Ventilation
Every activity we do in the house generates carbon dioxide, heat and moisture. These can range from mundane things like breathing to high energy activities such as cooking, taking a shower, drying your clothes, microwaving your food and many others.
Through a process called convection, the moisture generated during these day-to-day activities will rise to the top of the roof. This convection can be a huge liability if your roof or attic is not well ventilated.
If the roof is not ventilated, the moisture will condense in the loft spaces and it begins seeping into the roof’s support structures which are usually made of wood or concrete. The trapped moisture creates a damp condition where the moulds will thrive. It can also weaken the underlying structure leading to costlier maintenance in the future.
This situation is generally dangerous because it is not easily noticeable unless it is very cold outside. So the damage can go on for a long time and by time you realize something is wrong, it will probably be too late and you will be grappling with serious roof repair needs.
Effect of Poor Ventilation on Energy Bills
Without proper attic ventilation, you will probably have to rely on artificial ventilation which drives up the energy costs. Good attic ventilation eliminates the need for air conditioning and will slice off a part of your monthly energy expenditure. Roof ventilation also provides natural cooling for your attic thus eliminating the need for artificial cooling.
Excess Heat Can Damage the Roofing Material
Without proper roof ventilation, there will be a massive build-up of heat in the roofing area and around support structures during the summers. High roof temperatures will have a scorching effect on the materials used in the roofing such as the shingles. This will shorten the lifespan of your roofing necessitating a premature roof replacement. Not to forget that poor roof ventilation will also cause the growth of mold and mildew due to condensation. This will lead to a slow disintegration of the roofing framework and shorten its lifespan even further.
By installing roof ventilation such as exhaust and intake vents, you allow cool and dry air to get into the roof while pushing the warm and moist air out. This prevents condensation and also reduces the attic temperature, factors that help lengthen the lifespan of your roofing. Ideally, the attic temperature should be as close as possible to the temperatures outside in order to prevent condensation and the formation of ice dams during the winter seasons.
Manage Interior Temperature Extremes
Good ventilation will help you mitigate the impact of interior temperature extremes. Without good roof ventilation, you will grapple with a situation where the lower floors of your home are cooler while the upper floors are practically unliveable. This effect is more pronounced in ranch-style homes that are not well ventilated. Ideally, you would want an interior living environment where the temperatures are more evenly distributed. Well-vented roofs ensure that your home is comfortable at all times throughout the year.
Building Code of Australia Ventilation Requirements
The installation of ventilation is also a regulatory requirement in Australia. Various building codes in disparate localities generally specify the ventilation requirements that are needed to ensure compliance. According to the Building Code of Australia (BCA) regulations (http://www.build.com.au/bca-ventilation-requirements), the window size should, for example, make up at least 10% of the floor space in the room so as to allow in natural lighting. The regulations generally require that every room incorporate cross ventilation. A professional roofing expert will be able to translate these technical requirements into a practical roof venting system that will satisfy your ventilation needs.
However, it is important to note that ventilation alone is not enough to ensure optimal temperature regulation and smooth airflow in the building. Where there is high environmental humidity, good ventilation will only bring in more humid air into the house. In such situations, you will need to make additional investments in your home insulation by installing extra exhaust fans and humidity sensor fans in high humid areas of the home such as the bathrooms. These will ensure that the humidified air is quickly pumped out of the house into the atmosphere.