UK Construction Journal - Issue 1 - April 2026 - Flipbook - Page 16
CASE STUDY 03.
Structural Rescue & Redesign of Cantilever Stone Balcony
1–3 Grosvenor Crescent, London SW1X 7EE
The Problem
A Grade II listed curved Portland stone cladding at Grosvenor
Crescent suffered severe structural cracking, including:
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Large longitudinal cracks along the full span
Radial cracking through slab depth
Panel displacement
Loss of structural continuity
The proposed system:
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My Intervention
I led the structural resolution strategy.
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Instead of replicating the failed brittle stone system, I proposed:
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A Reinforced Concrete Monolithic Balcony
This was not a repair.
It was a complete structural re-engineering of the cladding
concept while retaining its architectural identity.
Converts brittle failure risk into controlled
ductile behaviour
Maintains original 115–135mm visual thickness
Avoids invasive façade reconstruction
Preserves historic air bricks and detailing
Minimises impact to listed structure
Eliminates the risk of sudden catastrophic stone failure
Outcome
The cladding was transformed from a structurally unstable
historic liability into a modern engineered structural element
concealed within traditional form.
Engineering Validation
A full Finite Element Model (FEM) analysis was carried out for
the curved geometry.
Project Team
• Structural Inspection (Existing): Pringuer-James
Consulting Engineers (PJCE)
• Heritage Engineering Advice: Alan Baxter Ltd
• Specialist Stone Consultant: PAYE Stonework &
Restoration
• Architect: Aukett Swanke
• Structural Modelling & Design: Quorum Consulting
Engineers
• Contractor: Amtaargc Ltd
Why This Was the Correct Solution
Stone behaves in a brittle manner.
Reinforced concrete behaves ductile.
The original failure mechanism showed downward rotation
at the free edge, full-depth cracking, and loss of structural
continuity under cantilever action.
UK CONSTRUCTION JOURNAL
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