2025
Finsbury Dials, London
Finsbury Dials: Sustainable Waterproofing in the Heart of London’s Financial District
Project Description
20 Finsbury Street, London EC2Y 9AQ
Located in the heart of London’s financial district, Finsbury Dials is an expansive office building which was built in the 1980s and is situated at the intersection of Chiswell Street and Finsbury Street.
As part of plans to renovate the existing building, works began in August, 2024 on the refurbishment of a basement within the offices for both commercial and some habitational purposes.
Sika partner Renlon, a specialist in structural waterproofing and building preservation for both residential and commercial properties, was selected for the work, which would entail waterproofing the 2,000 m² space.
Renlon engaged Sika in order to provide a sufficient solution to complete the waterproofing of the Finsbury Dials basement and, because of company’s agreement as a registered contractor, Relon could draw upon the Sika team’s expertise, working together on the solution whilst also offering a guarantee on the product used to the customer.
Project Participants
Client: Erith
Contractor: Renlon
Market Sector: Commercial
Products: Sika®-1 Pre-Bag LC Render System
Project requirements
The Finsbury Dials project team wanted to limit the usage of a cavity drain system in order to reduce the maintenance needed on the project.
The basement had a number of live leaks, which meant the team needed a system which was durable enough to deal with this problem, plus one which could withstand high water pressure. Additionally, any time saving opportunities on the programme would also be a driver for the products which would be selected.
It was decided that with these requirements in mind, a render was therefore the most suitable solution for the space.
Sika Solution
The Sika®-1 Pre-Bag Low Cement Render System was chosen by the contractor because of the speed of application it could offer and its sustainability benefits.
Designed to control water ingress on new build and repair and refurbishment projects, Sika®-1 Pre-Bag LC Render System is a one-component, multi-coat render system with a spray application designed to decrease installation time.
A Type-A waterproofing system according to BS8102: 2022, the product provides quicker installation and less downtime in between coats, thanks to its faster initial dry time. This proves important for projects like Finsbury Dials where many different trades are operating in order to complete the job, and delays must be kept to a minimum. Additionally, it offers greater adhesion to the application surface and less permeability.
The product has a low cement formulation, reducing cement content by 80% compared to traditional renders. This makes it a more environmentally friendly and attractive option for bigger projects as by replacing cement with alternative materials, the system helps reduce the overall CO₂ impact of construction projects. Furthermore, the spray application of the product decreases wastage.
Suitable for use on concrete, brick, and structural blockwork, both internally and externally, the product can be used as a solution for waterproofing walls and ceilings in new build, repair, and refurbishment projects.
1,500 m² of Sika®-1 Pre-Bag LC Render was used at the Finsbury site, where it was installed onto an existing concrete slab and retaining walls. Construction joints were secured prior to the application of Sika®-1 Pre-Bag LC Render using the Sikadur-Combiflex® SG System. Significant preparation was carried out on the existing substrate to remove debris and ensure a suitable surface, key for the product’s application.
"Renlon collaborated closely with Sika, a leading company in building materials and waterproofing systems, and the design team to develop a tailored specification that would meet the unique needs of the client. The partnership between Renlon and Sika was instrumental in delivering a solution that was not only effective but also aligned with the high standards required for the project" Ben Fowler, Commercial Director and John Stevens Commercial Surveyor Renlon
"Sika®-1 Pre-Bag LC Render System was the perfect solution for this project. The programme constraints meant that it would have been difficult to install the original system and not cause delays. Switching to Sika®-1 Pre-Bag LC Render allowed us to provide an equally robust system without compromising the programme. The sustainability benefits were an added bonus, as we have drastically reduced carbon emissions by changing products" Chris Lee, Regional Manager for Sika