14/10/2026
An important change for owners of Listed Buildings 🏛️
The revised National Planning Policy Framework has changed how alterations to heritage assets should be assessed.
As highlighted recently in The Planner (21 September 2026), the familiar catch-all description “less than substantial harm” has been replaced by a clearer assessment of:
Positive effect | No effect | Harm | Substantial harm | Total loss
Perhaps more importantly, the starting point must be the significance of the heritage asset – what actually makes the building special – followed by a clear assessment of how the proposed work affects that significance.
For owners looking to extend, convert or adapt a Listed Building, this is an important distinction. Change to an old building does not automatically mean harm to its heritage significance. Good design can preserve the important elements, remove unsympathetic alterations and sometimes positively enhance the building.
At Darcy Architects, we regularly work with Listed Buildings and properties within Conservation Areas, balancing their historic significance with the practical need for buildings to continue to evolve and be used.
Reference: The Planner, 21 September 2026 – commentary on the revised NPPF heritage assessment framework.
