Location: Tower of London, London EC3N 4AB
Sector: Heritage / Commercial
Service: Measured Building Survey & 3D Revit Modelling
Project Overview
Fosse Surveying was appointed by CBRE to deliver a highly detailed Measured Building Survey and 3D Building Information Model (BIM) of Brass Mount, a historic defensive structure within the Tower of London complex.
This work formed a crucial foundation for upcoming restoration, conservation, and refurbishment planning, providing the client and design team with an accurate digital representation of the existing site conditions.
As a heritage asset with complex circular geometry, multilayered elevations, and sensitive access constraints, Brass Mount required exceptional accuracy and a methodology capable of capturing every architectural and structural nuance.
Scope of Work
The scope included a full measured survey of the internal and external structure, comprising:
- Basement, Ground Floor, First Floor and Roof Plans
- North, East, South and West Elevations
- Full 3D Revit Model of the existing building based on point cloud data
- Survey control networks established across multiple levels
- Survey wide geo-referencing for accurate vertical and horizontal alignment
Using Leica laser scanners, total stations and high-definition imaging, our team captured millimetre accurate geometry and elevations, ensuring the final model reflected every structural and architectural feature, from arrow slits and stone mullions to vaulted thresholds and parapet details.
Architectural Characteristics of Brass Mount
The Tower of London is one of the UK’s most iconic historic landmarks. Founded by William the Conqueror in the 11th century, the fortress complex has served many roles throughout its history, a royal palace, armoury, treasury, prison and military stronghold.
Brass Mount, located in the northern section of the Tower’s outer defences, forms part of the Tudor-period bastions introduced to strengthen the fortress against advances in artillery. Its curved geometry, deep defensive walls and layered internal spaces make it a uniquely challenging structure to survey. As a unique piece of London’s military heritage, any restoration or conservation work requires exceptionally accurate documentation to safeguard its architectural and historical significance.
Its architecture reflects over 900 years of continuous adaptation, combining Norman stonework, medieval battlements, Tudor additions, and later military fortifications. The structure incorporates a range of complex features, including:
- Thick defensive stone walls with irregular geometry shaped to absorb and deflect artillery fire
- Historic arrow loops, embrasures and recessed openings, each requiring detailed measurement for conservation accuracy
- Gothic influenced window and door surrounds visible across the façades, with carved stone mouldings and pointed arches
- Stepped parapets and battlements typical of Tower of London fortifications
- Multi-level circulation routes, including vaulted thresholds, internal staircases and elevated wall walks
- A raised roof zone with varied levels and plant access points, visible in the measured drawings and 3D model outputs
These architectural elements, combined with the circular plan, nonuniform wall thicknesses, and the adapted structures make Brass Mount a highly intricate site to document.
Working on a Sensitive Heritage Site in London
Surveying within a UNESCO World Heritage Site required careful planning, heightened security compliance, and a methodology that respected both the building fabric and the operational requirements of the Tower of London.
Key considerations included:
- Navigating restricted access routes
- Operating around ongoing footfall and controlled visitor movement
- Implementing non-invasive scanning methods to preserve the structure
- Coordinating with CBRE and site management for safe and secure access
Our team worked discreetly and efficiently, ensuring minimal visual impact while maintaining the highest accuracy standards expected for historic conservation projects.
Results & Client Feedback
The final outputs included:
- A full 3D Revit model representing all architectural and structural elements of Brass Mount
- 2D CAD floor plans, roof plans, and elevations (DWG/DXF)
- Geo-referenced building data aligned to a consistent vertical/horizontal datum
- Visual renders and CGIs used for planning, design, and stakeholder communication
These deliverables provided CBRE and the heritage design team with a reliable and fully coordinated dataset, enabling them to progress with restoration proposals confidently and efficiently.
Feedback from the client highlighted the clarity, accuracy, and depth of detail captured in the model; particularly the precise representation of the curved geometry and the historic façade elements.
Key Achievements
- Delivered a highly detailed 3D model of a sensitive and complex heritage structure
- Captured multi-level geometry with complete accuracy using advanced scanning workflows
- Produced a full suite of RICS-compliant drawings and BIM-ready outputs
- Supported conservation planning within one of the UK’s most historically significant sites
- Demonstrated Fosse Surveying’s capability in high end, specialist heritage surveying
Why Fosse Surveying Was the Trusted Partner for Brass Mount
The Brass Mount project showcases Fosse Surveying’s expertise in delivering precise, technically robust and conservation-sensitive surveys for historic and complex structures.
Our combination of modern laser scanning, experienced surveyors and rigorous methodology ensures every detail, from structural geometry to decorative stonework, is captured accurately, supporting architects, conservationists and estate managers in making informed decisions.
Whether working on heritage landmarks, commercial refurbishments or large-scale redevelopment projects, Fosse Surveying delivers data you can trust.