How To Ventilate a Flat Roof

24th May 2019 by in category News tagged as , , , , with 0 and 5
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Any roofing system needs to be equipped with the appropriate level of ventilation. This is just as important for flat roofs, as moisture and damp could otherwise build up over time. Not only can this lead to issues such as mould and water damage, but ventilation is often required in order to meet building regulations.

How To Ventilate a Flat RoofThis is why it is important that flat roofing in Cardiff addresses such issues from the very beginning. How are these systems installed and are there any factors to take into account?

The Differences Between Warm and Cold Flat Roofs

The disparities between these two types of roofs will often impact the type and level of ventilation that is required. Cold flat roofs consist of insulation that is placed between the underlying rafters.

On the contrary, warm flat roofs are equipped with a solid sheet of insulation that is placed directly atop the existing surface. Why does each require a different type of ventilation?

Ventilation Requirements for Different Types of Roofs

The main intention behind any insulation system is to provide a sufficient amount of space so that air can be properly circulated. This helps to reduce moisture levels and avoid other problems such as mould and rot. 

When referring to a cold flat roof, a type of ventilation known as a vapour layer must be placed directly beneath the existing insulation and above the underlying room. This is the best way to create a moisture-impermeable barrier.

However, this very same vapour layer will need to be located beneath the upper layer of insulation in the case of a warm flat roof. The main intention here is to prevent moisture from interacting with the insulation due to the rising air cause from thermal pressure in the room below. 


Please note that roof vents are normally required to aid in the ventilation process. There are a wide variety of these mechanisms although circular soffit vents and breather vents are the most common configurations. It is always best to refer to official guidelines so that the correct choices are made. 

KC Smith Roofing should always be called if you have a question regarding the ventilation of a flat roof or repairs in general. So, give us a call at your convenience to learn about the services that we have to offer.

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