State of the nation’s roofs: A top-down perspective

Recent data from Ordnance Survey has provided valuable insights into the state of the nation’s roofs, which could significantly impact the insurance industry. 

With the release of detailed roof data for more than 40 million buildings into the OS National Geographic Database, insurers will now benefit from being able to make more confident insurance decisions.

The OS NGD is already the definitive source of buildings intelligence in Great Britain, including insights on their use (such as commercial, retail, residential), construction material, age, number of floors (47 million in total), address count, and basement presence.  

All these features are available in the OS NGD Buildings theme alongside the new roof data. 

They can be cross-referenced with other OS NGD themes such as address and land use to unlock valuable insights that can improve risk assessment, manage accumulation, and understand exposure to climate change.

The data is regularly updated through automated feature extraction and artificial intelligence machine learning technology, ensuring that insurers have better access to accurate and trusted data for confident decision making.

The latest update introduces enhanced roof data, including thatch roofs, green roofs, presence of solar panels plus roof material, shape and aspect. 

This data is crucial for various applications, including enhanced risk assessment and pricing, improving underwriting performance.

Solar panels

For the first time, OS has also identified buildings with solar panels, revealing that 5% of buildings across Britain have them. 

This is particularly notable in Scotland, where the highest proportion of domestic solar panels is found.

Solar panels increase insurers’ exposure due to the risk of damage from severe weather (such as hailstorms and windstorms), theft, or vandalism. 

They can also potentially have a higher fire risk, especially if not fitted properly, leading to costly repairs. 

Homeowners may be unaware that they should inform their insurers about the installation of solar panels to cover the added value and potential risks associated with them. 

The new data will therefore be essential for enhancing pricing strategies. It allows insurers to proactively evaluate residential and commercial properties, including roof types, to ensure the appropriate policy is applied.

In recent years, the UK has experienced an increase in severe weather events, and in 2024, insurers paid out a record £585m for weather-related damage to residential properties and household items. 

Insurance companies are facing mounting challenges as they pay out claims related to property damage and flooding.

Roof type

The data also identifies whether roofs are flat or pitched, which is essential for assessing water ingress risk for property insurance. 

Pitched roofs, for example, offer better water runoff. The predominant orientation of roofs also enhances wind and storm modelling. 

Different roof types have varying wind resistance capabilities, and when combined with other property attributes such as building height or proximity to coast and other exposed locations, can provide enhanced insight into underwritten portfolios.

Data on roof material can also help identify potential fire risks. For example, thatch is found in only 0.1% of British buildings, with the highest total number in Sidmouth, East Devon, highlighting areas of ‘spikey exposure’ across the nation.

Through our partner network, OS is making this comprehensive roof data available to insurance companies to help them better manage their risks. 

The data is regularly updated through automated feature extraction and artificial intelligence machine learning technology, ensuring that insurers have better access to accurate and trusted data for confident decision making. 

In the future, OS plans to capture more detailed information about roof types, including their physical condition, providing greater insights and strengthening relationships between customers and insurers.

The state of the nation’s roofs is a critical factor in the insurance industry. Insurers can use the detailed roof data to improve their risk assessment processes. 

By understanding the exact shape, aspect, and material of roofs, insurers can make confident underwriting and claims decisions, more accurately model perils, and set premiums that reflect the more granular risk. 

This leads to more competitive pricing and improves overall customer satisfaction. The detailed insights from OS mark a significant step towards a more resilient and sustainable future.