55 Leroy Street

Creating a Roof Terrace Without Compromising the Waterproofing

Creating a Roof Terrace Without Compromising the Waterproofing

The Leroy Street project wanted to transform part of its roof space into a usable outdoor terrace for staff – creating an area where employees could take a break, host events, and enjoy views across the London skyline towards landmarks such as The Shard.

While the vision was straightforward, delivering a safe, compliant roof terrace without introducing unnecessary complexity into the build-up presented a significant challenge.

That’s where an integrated system approach proved its value.

The Challenge

The key challenge centred around the balustrade design.

Unlike many roof terraces, the terrace area did not extend to the edge of the building and therefore had no parapet wall available for fixing the balustrade.

Traditional options would have required:

• Penetrations through the waterproofing layer
• Multiple pitch pockets and waterproofing interfaces
• Additional structural steelwork
• Significant coordination between trades
• Increased costs and programme implications

The project team needed a solution that would provide the required edge protection while avoiding the complexity and risk associated with penetrating the roof structure.

Adding to the challenge, the terrace layout included multiple corners and directional changes, requiring careful coordination of the support system beneath the paving.

Solution & Process

To eliminate the need for waterproofing penetrations, the terrace was designed using BaseLink® integrated with the TerraSmart Lattice Frame system.

By connecting the balustrade directly into the terrace support structure, BaseLink® allowed the required edge protection to be achieved without:

• Penetrating the waterproofing membrane
• Introducing additional structural steelwork
• Creating complex waterproofing details

This significantly simplified coordination while helping preserve the long-term integrity of the roof build-up.

Technical Design Support

Due to the terrace geometry, careful planning was required to coordinate the lattice frame layout.

Working closely with the project team, we provided technical guidance throughout the design process, supporting the development of the subframe layout and helping to coordinate key interface details across the terrace. This included setting-out advice for the rail configuration, coordination of multiple corner transitions, and guidance on joist direction changes throughout the scheme.

This collaborative approach helped ensure the support structure could be installed efficiently while remaining aligned with the overall terrace design intent.

Bespoke Finishing Touches

To help deliver the desired aesthetic, the project also incorporated a bespoke powder-coated finish to the terrace support system, moving away from a standard specification to achieve the required visual appearance.

Additional custom detailing was also developed to support the functionality of the terrace and provide a seamless user experience.

Outcome

• Safe and compliant roof terrace delivered for staff use
• No penetrations through the waterproofing membrane
• Reduced coordination compared to traditional balustrade solutions
• Elimination of additional structural steelwork requirements
• Bespoke finish achieved to match the project vision
• Simplified installation through an integrated systems approach

Key Benefits

• BaseLink® integration removed the need for waterproofing penetrations
• Reduced programme and coordination risks
• Maintained roof integrity without additional structural interventions
• Detailed technical support throughout the design process
• Flexible system capable of accommodating complex terrace layouts

Summary

55 Leroy Street demonstrates how integrated terrace systems can solve complex detailing challenges without compromising design intent.

By combining BaseLink® with the TerraSmart Lattice Frame system, the project team was able to create a safe, functional roof terrace while avoiding the cost, coordination and waterproofing risks typically associated with traditional balustrade installations.

The result is a practical staff space with impressive views across London – delivered through a smarter, more coordinated approach to roof terrace design.

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