Sika provided concrete admixtures, waterproofing, and injection systems at Thames Tideway, London; untreated discharges near zero

Sika provided concrete admixtures, waterproofing, and injection systems at Thames Tideway, London; untreated discharges near zero

saw_Thames Tideway, London, UK

SIKA AT WORK THAMES TIDEWAY, LONDON, UNITED KINGDOM CONCRETE PRODUCTION: Sika® ViscoCrete®, Sika® Sigunit® WATERPROOFING: SikaInject®, Sika Waterbar®, Sika Elastomer®, Sika Tricomer®, Sikaplan®, SikaProof® CONCRETE REPAIR: Sika® MonoTop®, Sikadur® GROUTING: SikaGrout® ROOFING: Sarnafil®

SIKA AT WORK THAMES TIDEWAY, LONDON, UNITED KINGDOM 2 PROJECT DESCRIPTION The Thames Tideway Tunnel, often called London’s “Super Sewer”, is one of the UK’s largest ever civil engineering pro­ jects. Stretching 25 km beneath the River Thames, the tunnel captures and transfers sewage overflow that would otherwise enter the river, thereby protecting London’s environment and ensuring the city’s wastewater infrastructure remains fit for the next 120 years. Construction began in 2016, with comple­ tion scheduled for 2025. The project is operated by Tideway and supported by the UK government. Once operational, it will reduce untreated dis­ charges into the Thames from around 40 million tonnes per year to almost zero, significantly improving water quality and biodiversity in the capital. Sika contributed concrete admixture, waterproofing, and injection technologies for the project, supporting the pro­ ject’s durability, watertightness, and long-term performance requirements. PROJECT REQUIREMENTS The construction of a deep tunnel running up to 65 meters below the Thames presented extreme geotechnical and en­ vironmental challenges. The entire system had to withstand constant groundwater pressure, aggressive soil and water chemistry, and long-term structural loads. Strict durability and watertightness standards were set to ensure a 120-year design life with minimal maintenance. Tunnel segments, shafts, and connection structures required dense, impermeable concrete and high-performance water­ proofing systems that could be installed safely and efficiently under tight schedules. Sika’s experience in global tunnelling and infrastructure pro­ jects made it a natural choice for the project’s technical and environmental demands. SIKA SOLUTIONS FOR EUROPE’S LARGEST WASTEWATER TUNNEL

SIKA AT WORK THAMES TIDEWAY, LONDON, UNITED KINGDOM 3 SIKA SOLUTIONS Sika provided a comprehensive range of solutions cover­ ing concrete technology, waterproofing, repair and injection systems, supported by close technical collaboration with designers, contractors, and site teams. Solutions were applied across precast and in-situ concrete works, sprayed concrete operations, shaft waterproofing, cross passages, head hous­ es, and associated structures. Concrete admixtures Sika delivered a full range of admixture solutions for all con­ crete types used on the project: ́ Sikament® and Sika® ViscoCrete® admixtures For precast TBM segments, secondary linings, and dia­ phragm walls to achieve high workability retention, low permeability, and dense microstructure. ́ Sika® Sigunit® accelerators For sprayed concrete linings (SCL) used in shafts, tunnel enlargements, and cross passages, providing rapid early strength development and improved rebound control. ́ Concrete admixtures for grouting and precision placement Ensuring consistent performance in segment backfilling and void filling. Waterproofing and Joint Protection The tunnel relies on a multi-layered waterproofing concept us­ ing systems suited to deep, high-pressure environments: ́ Elastomer & Tricomer Waterbars Installed at key joints to prevent water ingress between concrete sections. ́ Sikaplan® membrane systems Applied in caverns and adits, providing durable, flexible waterproofing under high hydrostatic pressure. ́ SikaProof® pre-applied membranes Used for head houses and kiosk structures where ground conditions demanded a bonded waterproofing solution. ́ SikaInject® resins For sealing cracks, construction joints, and localized leak repairs during excavation, lining, and fitout. Concrete Repair, Bonding & Grouting ́ Sika® MonoTop® mortars and Sikadur® structural adhesives Used for defect repair, precision finishing, and strengthe­ ning works. ́ SikaGrout® Applied for bedding precast components, filling voids, and ensuring long-term stability. Roofing Solutions Sarnafil® roofing membranes Installed on above-ground kiosks and head houses, providing robust weather protection and long-term durability. Technical Services Sika Limited (UK) supported the project through: ́Mix design optimization for precast and in-situ concrete ́Material testing and quality control ́Waterproofing detailing support ́Onsite troubleshooting during excavation and lining works This hands-on involvement ensured consistent speci­ fication compliance across all three major tunnelling sections.

PROJECT PARTICIPANTS Owner/Client: Tideway Main Contractors: West Joint venture of BAM Nuttall, Morgan Sindall and Balfour Beatty Group (BMB JV) Central joint venture of Ferrovial Agroman UK and Laing O’Rourke ­Construction (FLO JV) East joint venture of Costain, Vinci Construction Grands Projets and Bachy Soletanche (CVB JV) Engineer: Jacobs / Atkins / Arup Joint Venture Sika Organization: Sika Limited (United Kingdom) © SIKA SERVICES AG / WATERPROOFING / 04.2026 THAMES TIDEWAY, LONDON SIKA SERVICES AG Tueffenwies 16 CH-8048 Zurich Switzerland Contact Phone +41 58 436 40 40 www.sika.com Any product name or reference reflects the Sika product name at the time of creation of this document and may differ from the product name or reference during past events. Our most current General Sales Conditions shall apply. Please consult the most current local Product Data Sheet prior to any use.