Inspecting Spires, Towers and High-Level Stonework
Spires, towers, and high-level stonework are among the most visually prominent and structurally vulnerable elements of historic buildings. Their height, exposure, and complexity make them difficult to inspect regularly, yet deterioration in these areas can present significant risks if left unnoticed.
Aerial inspection using drones provides a safe, non-invasive method for observing these structures closely. When used appropriately, it supports proactive stewardship, informed decision-making, and responsible heritage management.
This guidance explains why spires and towers require particular attention, how aerial inspections are used in heritage contexts, and what their limitations are.
Why spires and towers require careful monitoring
High-level structures are exposed to more severe environmental conditions than most other parts of a building. Wind, driving rain, frost, thermal movement, and biological growth all contribute to gradual deterioration.
Common issues observed in spires, towers, and high-level masonry include:
-
Stone erosion and surface loss
-
Open joints and mortar decay
-
Cracking or displacement of masonry units
-
Deterioration of metal elements, fixings, or pins
-
Blocked or failing rainwater details
Because these features are rarely visible from ground level, such issues can develop unnoticed for long periods.
Challenges of traditional inspection methods
Inspecting spires and towers using traditional access methods often involves scaffolding, mobile access platforms, or rope access. While sometimes essential, these approaches can introduce challenges:
-
High cost and long lead times
-
Disruption to the use of the building
-
Increased risk to contractors, volunteers, and the public
-
Potential impact on historic fabric through fixings or loading
As a result, access is often delayed until problems become urgent, increasing both risk and expense.
How aerial inspections support safer observation
Those responsible for heritage buildings are often required to demonstrate that reasonable steps are being taken to inspect and maintain them.
Aerial inspection reports can support this responsibility by:
-
Providing dated photographic records
-
Clearly describing observed condition
-
Highlighting areas that may require professional advice
-
Supporting annual reports, fabric logs, and handovers
They do not replace professional judgement, but they provide clear, objective information to inform it.
What aerial inspections are particularly useful for
In heritage contexts, aerial inspections are especially valuable for:
-
Routine condition monitoring
-
Comparing condition year-on-year
-
Identifying areas that may require closer professional review
-
Informing whether physical access is justified
-
Supporting risk assessments and maintenance planning
They are most effective when carried out regularly and consistently, using comparable viewpoints to track change.
Understanding limitations
Aerial inspections of spires and towers are visual and non-invasive. It is important to understand their limitations.
They:
-
Cannot assess concealed conditions or internal voids
-
Do not confirm structural performance or stability
-
Cannot replace hands-on investigation where this is required
Where concerns are identified, further investigation by appropriately qualified professionals may be recommended.
Integrating aerial inspections into heritage management
When used as part of a broader inspection and stewardship strategy, aerial inspections help custodians to:
-
Reduce reliance on emergency access
-
Plan targeted investigations more effectively
-
Demonstrate responsible monitoring and oversight
-
Build a clearer understanding of long-term condition trends
They support — rather than replace — the work of conservation architects, surveyors, and engineers.
About this guidance
This guidance is published by ThreeWeave to explain best practice in the aerial inspection of spires, towers, and high-level stonework on heritage buildings in the UK.
ThreeWeave provides inspection, data collection, and reporting only. Any conservation assessment, advice, or remedial work should always be undertaken by appropriately qualified specialists.