Archive for August, 2025

July & August Social Media Recap

🔹 Basement Waterproofing in Chelsea, London 

We’re proud to share that MacLennan has been appointed to deliver the waterproofing design and installation for a significant new basement development in Durham Place, Chelsea.

This project comes with a unique backstory — the original property was tragically damaged beyond repair following the collapse of a neighbouring building and was subsequently placed under a Dangerous Structures Notice.

Working alongside the highly respected team at Forcia, specialists in complex and high-risk structural work, we ensured the safe demolition of the existing structure and the installation of piling to secure the new basement box.

July Social post 4 Durham place

Following a detailed site inspection, our experienced and qualified surveyor recommended a dual waterproofing strategy in accordance with BS8102:2022 – the British Standard for protecting below-ground structures from water ingress.

🔹 Primary Protection: A cementitious coating applied to the internal surfaces below ground to reduce water penetration.

🔹 Secondary (and most critical) Protection: A Type C Cavity Drain System – a maintainable and therefore guaranteeable solution that forms the backbone of long-term waterproofing performance.

This approach ensures robust protection and peace of mind for the client, aligning with best practices and industry standards.

🔹Waterproofing a Historic London Landmark

We were recently contacted to provide our specialist waterproofing design for a large existing basement beneath the Grade II listed Marlborough Head pub in London, which is undergoing a major renovation.

Our team has now completed the installation of a comprehensive cavity drain system throughout the basement and vaulted areas. 🎥 The video offers a walk-through of the newly installed system, showcasing how this once damp and unusable space is being transformed into a dry, habitable environment, ready for its future purpose.

As more and more existing basements in London are being converted into living or commercial spaces, it’s essential to involve waterproofing experts early in the process. Consulting with professionals from the outset, ideally from RIBA Stage 3, ensures that the design is tailored to the unique challenges of each property.

✅ At MacLennan, we take full responsibility for the waterproofing design, backed by our extensive experience and £10 million PI cover. We don’t just install systems, we take the risk out of waterproofing.

🔹 New Project Introduction: Garland Park with Esquire Developments

We’re excited to be working with new clients, Esquire Developments, on the Garland Park project, transforming the former Benenden Hospital brownfield site into a stunning development of 87 new homes.

Our team recently visited the site to review groundwork progress ahead of our installation phase, ensuring everything is in place for our technicians to begin waterproofing.

August Social media Benenden Hospital

🔹 MacLennan has been appointed to design and install waterproofing systems for 15 high-end basement units within a terrace.
🔹 Our CSSW & WDS qualified design team has specified a dual waterproofing approach, including a cavity drain system, to ensure the solution is repairable, maintainable, and fully compliant with BS8102:2022 for Grade 3 habitable spaces.
🔹 Each basement will be independently guaranteed, offering tailored protection for every property.

We’re proud to deliver robust, future-proof waterproofing solutions backed by our expertise and industry-leading guarantees.

Resin Injection August 2025 Newsletter

Aug newsletter - resin injection

Basement waterproofing remains a critical concern for construction professionals, especially in urban environments where below-ground structures are increasingly complex. Among the most effective and minimally invasive solutions available today is resin injection, a technique that offers both structural reinforcement and watertight sealing.

Resin injection is normally required where the primary or existing waterproofing has failed. The structure is leaking. A remedy is required.

What Is Resin Injection?

Resin injection involves the use of polyurethane , Acrylic or epoxy resins to seal cracks, joints, and voids in concrete structures. The process typically includes:

  • Identifying the source of water ingress
  • Drilling ports along the affected area
  • Injecting resin under pressure, allowing it to expand and fill the voids
  • Curing, which forms a watertight seal that adapts to future movement

Polyurethane resins are particularly effective for active leaks, as they expand upon contact with moisture. Epoxy resins, on the other hand, are ideal for structural repairs due to their high bonding strength acrylic resins are often used where movement is likely.

Other resin options are available for different scenarios such as curtain wall installations and movement joints.

Resin Injection
Resin Injection - Luton street 15.02.21 (3)

Diagnosing and Specifying the Solution

Once the source of a leak is diagnosed by the MacLennan surveying team, a tailored specification is prepared for remediation. This ensures that every intervention is based on a thorough understanding of the structure and the nature of the ingress.

  • Large voids are chased out and filled with watertight concrete repair mortar.
  • Cracks and deep voids are injected with our polyurethane resins, which react with water to seal the area permanently, preventing further ingress.

Tackling Joint Leaks with Precision

Very often it  is joints, rather than cracks, that are the primary source of leaks in basement structures. The resin injection of construction joints must be carefully considered, as these joints can be  designed to accommodate movement. Incorrect material selection or overfilling can lead to future complications.

MacLennan’s resin injection engineers bring over 30 years of experience to this highly specialised form of waterproofing. Our expertise have been applied to some of the most technically challenging projects in the UK.

Why It Matters for Basement Projects

Basements are especially vulnerable to water ingress due to their below-ground location. Traditional waterproofing methods, such as external membranes or tanking, can be disruptive, costly, and impractical or impossible for retrofit projects. Resin injection offers several advantages:

  • Non-invasive: No need for excavation or extensive demolition
  • Fast application: Most jobs can be completed within hours
  • Durable: Resins are resistant to chemicals, movement, and long-term moisture exposure
  • Cost-effective: Reduced labour and material costs compared to traditional methods
concrete
Resin injection

Applications in Design and Remediation

For architects and engineers, resin injection provides flexibility in both new builds and retrofit scenarios. It can be used to:

  • Seal construction joints and cold joints
  • Repair cracks caused by settlement or thermal movement
  • Reinforce structural integrity in aging concrete
  • Complement other waterproofing systems as a secondary barrier

Conclusion

Resin injection is not a one-size-fits-all solution, but when applied correctly, it offers a high-performance, low-disruption method for basement waterproofing. For construction professionals, understanding its capabilities and limitations is key to delivering resilient, watertight structures.

Resin injection will never be the primary waterproofing except in White tank scenarios for maybe a Carpark or tunnel.

For habitable construction where finishes are to be installed. Resin  injection will be used to stop water ingress prior to installation of the waterproofing system.

 

Comprehensive Support from Survey to Completion

MacLennan surveyors investigate, report, and recommend the correct course of action, supplying fully itemised costs for all aspects of the work—including coordination with main contractors where necessary. The work is then carried out to the highest standards, leaving clients with the confidence that their basement is now fully watertight.

 

Please watch our resin injection video below...

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