Heritage Lantern Restoration: Hammersmith Bridge

Pudsey Diamond Engineering Ltd commissioned by FM Conway to execute a comprehensive restoration and refurbishment of 21 Heritage Lanterns for the Grade II listed Hammersmith Bridge. The project also included the design and manufacture of a brand-new replica lantern to replace a missing unit, ensuring structural and uniformity across this iconic London structure.

The primary objective was the integration of energy-efficient LED optics while strictly maintaining the historic fabric and classic appearance of the bridge. Given the landmark status of the bridge, the refurbishment was delivered in carefully coordinated phases to align with ongoing remedial works being conducted by the London Borough of Hammersmith & Fulham Council.

Engineering Assessment and Challenges

A preliminary factory inspection of a sample unit identified several systemic mechanical and structural failures that required specialist intervention. For a Grade II listed asset in a high-vibration, riverside environment, standard maintenance was insufficient. The following technical issues were documented:

• Structural Safety: The original hinged latches were found to be unreliable. Under high-wind or adverse weather conditions, the lantern lids were prone to opening, presenting safety concerns and leaving internal electrical components exposed.
• Fixing Hardware Failure: The post-mount adaptor spigot bolts were seized or missing. This prevented secure mounting to the bridge infrastructure and required a complete overhaul of the fixing hardware.
• Glazing Degradation: The original glazing panels exhibited significant damage, graffiti and a loss of clarity, which impeded the light distribution and compromised the lantern’s historic appearance.
• Modern Needs: Fitting modern high efficiency LEDs required the design of new internal mounting infrastructure that could function within the original housings without altering the external architectural profile.

Technical Solutions and Methodology

The refurbishment followed a controlled, multi-stage engineering program at the dedicated Pudsey Diamond factory facility to ensure long-term durability.

1. Controlled Disassembly and Assessment

Lanterns were collected from the site in phases. Each unit was stripped to its component parts under factory conditions to allow for a full structural assessment. While the frames were confirmed to be generally sound, the internal components required total replacement or remediation.

2. Surface Restoration and Protection

All cast lantern components were stripped of existing paint and shot-blasted to remove corrosion. Following this, they were re-painted to the colour specification given by the client to ensure a durable, uniform and professional finish across the bridge.

3. LED Integration and Optics

To modernise the illumination, Pudsey Diamond designed and manufactured a bespoke Stainless steel adaptor plate. This plate serves as the precise mounting interface for a [32 LED Array]. These Energy-efficient LED optics provide precise light distribution and significantly reduce energy consumption compared to legacy systems.

4. Environmental Sealing (IP66)

To protect the sensitive electronics from the harsh maritime environment of the River Thames, the units utilise Pudsey Diamond’s proprietary ClamPD® seal technology. This ensures the internal gear tray achieves a unique IP66 rating, providing a dust-tight seal and protection against water ingress.

5. Mechanical Remedial Works

Engineers addressed the mounting failures by removing the seized and undersized spigot bolts. The threads were re-tapped to an M10 specification to allow for the installation of new, larger fixing bolts. These fixings were also re-painted to match the Client's specified colour. Additionally, the unreliable original latches were replaced with robust new hinged components, a safety recommendation based on previous refurbishment experience.

6. Glazing Replacement

The lanterns were fitted with Custom polycarbonate panels. Eight panels were manufactured per unit using textured and frosted polycarbonate. This material was selected for its high impact resistance and its ability to replicate the aesthetic of traditional glass while providing a superior environmental seal.

Quality Assurance and Outcome

Before delivery back to the site, every unit underwent Full System Testing. This rigorous quality assessment protocol included comprehensive electrical safety checks, mechanical torque testing of the new M10 fixings and sealing verification to confirm IP66 integrity.

The project delivered a fully refurbished suite of Heritage Lanterns that meet modern safety and efficiency standards. The bridge maintains its original architectural character, now supported by:

• Modern, high-efficiency LEDs that provide uniform, energy-efficient illumination.
• Improved safety through robust redesigned hinges and upgraded M10 fixtures.
• Consistent aesthetics with uniform painting of the Heritage Lanterns and post-mount adaptor spigots.
• Long-term reliability via enhanced sealing and a strengthened Stainless steel adaptor plate.

Through technical precision and close collaboration with FM Conway and the London Borough of Hammersmith & Fulham Council, Pudsey Diamond Engineering Ltd ensured the lighting element of this iconic landmark was returned to its former glory in a time-critical manner.

Start Your Project

Whether you are looking to upcycle original lanterns or require precision-engineered replicas to match a period aesthetic, our facility provides the full engineering process in-house. From bespoke fabrication to modern LED integration, we ensure your project meets modern compliance without losing its historic character. Ready to discuss your heritage refurbishment? Contact our sales team today.