How to insulate a curved roof

Weymouth Wave

Curved roofs are a unique and spectacular architectural feature but incorporating these into a building doesn’t mean that you have to compromise on thermal efficiency. In this blog post we take a look at one method of insulating a curved roof.

When building a roof there is obviously a requirement to meet the Building Regulations or Standards, which dictate what the minimum U-value is that your roof should meet. We’ve given more details about exact values required on our website, and even though curved roofs are not specifically mentioned in the regulations, there is a requirement to make sure the U-value of a curved roof meets the standards required for flat roofs.

It is possible to insulate a curved roof and still provide a high level of thermal performance. A curved roof can give a building a distinctive aesthetic appearance without compromising on performance, thickness or thermal efficiency.


We have developed a curved roof board, based on Thermaroof TR27 LPC/FM boards. The board is designed to curve around the roof, while still providing the levels of insulation required on both convex and concave roofs. The standard methods of fixing the insulation and applying waterproofing, as described in our literature can then be used. Double layers of insulation can be used with this method to reach even lower U-values.

This method can be used to insulate roof radii as small as 1.5m. U-values can be calculated on a case by case basis by contacting our technical department.

Case Study – Weymouth Wave

Weymouth Wave

Building a curved roof can produce an iconic look for a building; for example Weymouth Fire Station, where an eye-catching wave form roof has made it a local landmark. Graham Stevenson, Director at design practice Tetris Solutions, explained ‘The wave-form roof was an integral part of our design … as it emphasises Weymouth’s close relationship with the sea.’

The wave-form roof was an integral part of our design

The limitations on the height of the building meant that other flexible solutions could not be used to achieve the U-values required. It was achieved by using over 5000m2 of Thermaroof TR27 LPC/FM which provided the high levels of thermal performance required while bending to cover the 2.5m radius. More details on the project can be found on our website.

If you are interested in learning more about how to insulate a curved roof take a look at our website or contact the Technical Department.

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Kingspan Insulation is a market leading manufacturer of optimum, premium and high performance rigid insulation products and insulated systems for building fabric and building services applications.

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