Why is Roof Ventilation Important?

Why is Roof Ventilation Important?

Our modern lifestyles lead to a much larger amount of heat being produced within our homes and properties; and as we all know, heat rises. This leads to our roof and attic spaces being filled with this rising warm air. In this hot air is moisture, and when it enters roof spaces it comes into contact with cold surfaces and condensates.

The build-up of excess moisture and condensation in your roof space can lead to several common issues including mould, dampness and mildew; which can affect your physical health by reducing the quality of the air you breathe. In much more serious cases, this accumulation of moisture can compromise the structure of your roof, again causing a physical risk and the financial cost of repairs.

To prevent this build-up of moisture, effective roof ventilation creates a constant airflow throughout your roof space. Dispelling the hot air and the moisture it contains, before it can come into contact with the cold surfaces and turn into condensation.


What building regulation guidance is there on roof ventilation in the UK?

The ventilation of roof spaces is included in the BS 5250 Management Of Moisture In Buildings. Updated in 2021, the latest version of this guide (BS 5250:2021) includes updated guidelines and presents practical strategies for managing moisture in buildings. The latest update is unique because it deals with all forms of water, whether it's vapour, liquid, or solid, and explores how they interact with each other within buildings and how they can be effectively managed.

In the case of roof ventilation, BS 5250:2021 covers the common reasons for moisture buildup in buildings, such as rising dampness, leaks in the roof, and condensation. This edition provides more detailed information on roof ventilation, particularly focusing on pitched roofs, with expanded and clearer instructions on how to ensure proper ventilation in the roof space.


What causes a build-up of moisture in roof spaces?

Identifying and reducing or removing the sources of moisture within your home is often the first stage in effectively managing the amount of condensation or moisture that ends up in your attic or roof space.

According to City of London research, the average UK household produces an incredible 15 litres of moisture within the home every day.


Everyday Activities

Any process within the home that involves heating or hot water produces steam or excess heat that warms the surrounding air causing it to rise and enter the roof space. This includes cooking, showering, bathing, drying laundry, central heating, radiators and more.



The UK weather is no stranger to rain, and the levels of humidity are increasing year on year. These weathers provide more opportunities for water to enter your roof space. Although a leaking roof is a much more serious problem that will need to be repaired to prevent more water from getting into and damaging your roof space, effective roof ventilation can ensure that any trapped moisture after repairs can naturally be removed.



Keeping our homes warm and the temperature regulated to reduce energy use has led to the use of large amounts of insulation in building works and even its inclusion in building regulations. From packing the walls and ceilings to ensuring all windows and doors are sealed, our properties are now much more efficient at retaining heat in the colder months. Along with the retention of this heat, is the retention of the moisture that exists within warm air. Creating the right balance between effective insulation measures and appropriate roof ventilation provides the perfect solution to prevent the build-up of dampness and mould to maintain your air quality.


Building Materials

Much more common in new builds than older properties, the building materials used in construction can sometimes hold a reasonable amount of residual moisture. As these materials age in addition to being heated and cooled by the weather or your heating system, the moisture will naturally be released.


How to reduce the amount of moisture and condensation in your property?

It is impossible to completely remove all moisture and condensation from reaching the roof space but there are ways in which we can reduce the amount. Firstly, reduce the amount you produce by minimising the amount of excess heat and steam you produce. This can include taking shorter showers or drying clothes outdoors.

Secondly, you can look at implementing measures to better ventilate your home whilst these activities are going on. Examples of how you can do this are installing extractor fans in the bathroom and kitchen, opening windows to create natural air flows or using products like dehumidifiers.

Even though these measures can reduce the amount of warm air that reaches our attics and roof spaces, as mentioned, it is not possible to completely prevent it. This is why effectively ventilating your roof to remove the excess moisture and condensation is vital.


What to consider before ventilating your roof space?

Creating the best system to ventilate your roof space is dependent on the characteristics of your roof. Including whether you have a pitched roof or a flat roof, whether it is typically cold or warm, and its general structure.

The most common example is the ventilation of a roof space that includes a loft conversion, in this instance, you will require additional ventilation in the roof space than in a standard roof. To best understand speak to a professional roofer or read our Roof Ventilation Guide.


What are the different types of Roof Ventilation?

There are many different ways that you can ensure that you have effective ventilation in the roof space of your home or property. Modern roof ventilation solutions are available in a selection of types, styles and designs.

The most common solution is the inclusion of Roof Tile Vents. Also called in-line roof vents, these blend into the surface of your roof and simply look like another roof tile. However, they are intelligently designed to draw in cool air from outside to circulate your roof space and displace the warm air containing moisture. They can also be connected to kitchen or bathroom extractor fans to assist in immediately removing steam and warm air from your home or property before it reaches your roof space.

Other common roof ventilation systems include ridge vents and eaves vents. Rather than sit within the roof tiles and provide continuous natural airflow throughout your roof space, the ridge vents fit into your roof's ridge to ventilate the high-level roof space, and eave vents fit into the eaves of your roof to ventilate low-level roof space.

Typically, combining different roof ventilation systems with roof tile vents is the best way to ensure efficient airflow through your roof space.

If you need clarification on what the best roof ventilation solution is for your property, then feel free to get in touch with us at Beddoes Products today, or read our full Guide to Roof Ventilation.
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