Sustainable materials and the changing cost of rebuilding
An office built with engineered timber may have a detailed account of its carbon footprint. At insurance renewal, there is another question to ask: does the buildings sum insured reflect what it would cost to rebuild that particular office after a major loss?
Lower-carbon construction may affect the materials and methods needed to put a building back. There is no standard “green” amount to add to its rebuild figure. The useful starting point is to know what the building is made of and whether the current figure reflects it.
Why do the materials matter?
Timber framing is already familiar in housing. The government’s timber roadmap for England cites a 2019 comparison in which 92% of new-build homes in Scotland used timber frames. It also distinguishes established timber frames from newer mass timber systems, which can be used in larger buildings such as offices.
The practical question is which construction system the property uses. A broker does not need to price its components. Flagging that a building has a timber structure, and sharing any description the client has, gives the assessment team a starting point.
This can start with a simple conversation. What materials does the client know were used? Has the building changed since its last assessment? A description of any unusual features is useful, with drawings or specifications added if the client has them. The assessment team can then say whether it needs anything more.
How could this affect the rebuild figure?
The original construction price offers some context, but rebuilding involves more than buying the same materials again. Labour, access, demolition and professional fees may also affect the cost, as we explain in our mid-year look at construction costs.
For a building with lower-carbon materials, the aim is to make sure its construction is reflected in the assessment. That does not mean assuming it will cost more to rebuild. It means giving the assessor enough information to consider the building itself. An indexed increase to an existing figure cannot add a construction detail that was missing from the original assessment.
What about insurance pricing?
The rebuild figure helps inform the amount of buildings cover. The insurer also considers the building’s construction when deciding what cover and terms to offer. For some mass timber buildings, questions about fire, water damage and repairability may be relevant.
Insurer approaches vary. In 2025, Aviva expanded its mass timber proposition for certain large commercial properties. That is an example of an insurer assessing this type of construction, rather than a guide to what another insurer might charge.
A lower-carbon label does not reveal the likely premium. Sharing an accurate description with the insurer gives it the information to consider the risk.
A simple check at renewal
Three questions can get the conversation started:
Have you reviewed the current rebuild cost assessment with the client to check it describes the building as it stands, including any unusual materials?
Has anything changed since that assessment, and what can the client tell us about it?
Does the insurer know about the building’s construction?
The client may have plans and detailed specifications, or only a basic description. Start with what is available. If the current figure may no longer reflect the building, speak to RebuildCostASSESSMENT.com about the property. We can discuss whether a Desktop or Site Assessment is suitable and what further information, if any, would help.
