Warm vs Cold Roofs

by | May 2, 2024 | Last Articles | 0 comments

Warm Roofs vs Cold Roofs: A Comprehensive Guide

The design and construction of a building’s roof can significantly impact its energy efficiency and ventilation requirements. One of the key factors in this is the positioning of insulation within the roof void, which determines whether it is a warm roof or a cold roof.

Understanding Warm and Cold Roofs

In a cold roof, the insulation is laid between and on top of the ceiling. This means that the loft space above the insulation is not heated by the building’s heating system and remains cold, hence the term ‘cold roof’.

On the other hand, in a warm roof, the insulation is in approximately the same line as the upper part of the roof structure. This means that the entire roof structure, including the loft space, is kept warm by the building’s heating system.

Ventilation Requirements

The type of roof has a significant impact on ventilation requirements. In a cold roof, ventilation is required in the loft space to prevent the build-up of condensation, which can lead to damp and mould issues. This is typically achieved through the use of eaves or ridge vents.

In contrast, a warm roof does not require the same level of ventilation in the loft space, as the insulation prevents condensation from forming. However, it is still important to ensure that any moisture that does get into the roof structure can escape, to prevent damp and rot in the roof timbers.

Energy Efficiency

Warm roofs are generally more energy efficient than cold roofs. This is because they prevent heat from escaping through the roof, reducing the amount of energy needed to heat the building. However, the installation of a warm roof can be more complex and costly than a cold roof, so it’s important to weigh up the costs and benefits.


Whether you choose a warm roof or a cold roof for your building will depend on a variety of factors, including your budget, your energy efficiency goals, and the specific requirements of your building. At Building Compliance Testing Ltd, we can provide expert advice and testing services to help you make the right choice for your project.

Remember, the right roof can not only make your building more comfortable and energy efficient, but also ensure it complies with building regulations and standards. So, it’s worth taking the time to understand the differences between warm and cold roofs and consider which is the best option for you.

For more information, please don’t hesitate to contact us. We’re here to help!