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.

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.

🔹 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

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 - 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

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...

JUNE Social Media Post Roundup

🔹Large Deck Over an Underground Car Park:

🔍 𝗦𝗶𝘁𝗲 𝗦𝘂𝗿𝘃𝗲𝘆 & 𝗪𝗮𝘁𝗲𝗿𝗽𝗿𝗼𝗼𝗳𝗶𝗻𝗴 𝗔𝘀𝘀𝗲𝘀𝘀𝗺𝗲𝗻𝘁
Our experienced surveyor recently visited this Bournemouth, mid-1970s purpose-built apartment complex comprising two 7-storey towers with a shared basement car park, to carry out a comprehensive inspection following reports of water ingress.
💧 𝗜𝘀𝘀𝘂𝗲 𝗜𝗱𝗲𝗻𝘁𝗶𝗳𝗶𝗲𝗱:
Water penetration was observed through the roof slab of the basement car park. The original deck was constructed using asphalt membranes, which are known to degrade under prolonged UV exposure. Over time, thermal expansion and contraction can lead to fatigue and cracking—especially at high-stress areas such as corners, structural junctions, and upstand details.

🔎 𝗞𝗲𝘆 𝗜𝗻𝘀𝗶𝗴𝗵𝘁:
It’s important to note that visible leaks on the underside of a concrete slab don’t always indicate the exact point of water entry. Water can migrate through construction joints, and movement joints before becoming visible below.
🏗️ 𝗦𝘁𝗿𝘂𝗰𝘁𝘂𝗿𝗮𝗹 𝗢𝘃𝗲𝗿𝘃𝗶𝗲𝘄:
The basement structure consists of reinforced concrete downstand beams supporting a 150mm thick slab. The ground-bearing slab includes perimeter edge thickenings and reinforced concrete walls to retain surrounding ground levels. Our inspection also highlighted the need for upstand and concrete repairs in several areas.
We’re now working closely with the client to develop a robust waterproofing solution tailored to the unique challenges of this buried deck system.

🔹Semi-Basement Extension, Salisbury: Following our pre-construction waterproofing survey, our technicians are now on site installing a 𝗧𝘆𝗽𝗲 𝗖 𝗰𝗮𝘃𝗶𝘁𝘆 𝗱𝗿𝗮𝗶𝗻 𝗺𝗲𝗺𝗯𝗿𝗮𝗻𝗲 𝘀𝘆𝘀𝘁𝗲𝗺 to protect the newly built semi-basement extension at this 𝗚𝗿𝗮𝗱𝗲 𝗜𝗜 𝗹𝗶𝘀𝘁𝗲𝗱 property in Salisbury.
Although not a full basement, the structure still requires effective protection against water ingress to ensure it remains dry and habitable—fully compliant with 𝗕𝗦 𝟴𝟭𝟬𝟮:𝟮𝟬𝟮𝟮 standards for below-ground waterproofing.

💧 𝗗𝗿𝗮𝗶𝗻𝗮𝗴𝗲 𝗦𝘁𝗿𝗮𝘁𝗲𝗴𝘆 – Gravity-Fed System:
As part of our design, we offered the option of a sump and pump system to manage any potential water ingress. However, the client opted for a gravity-fed drainage solution, which is a passive system that relies on natural fall to direct water away from the structure.

This approach involves:
✅ 𝗗𝗿𝗮𝗶𝗻𝗮𝗴𝗲 𝗰𝗵𝗮𝗻𝗻𝗲𝗹𝘀 integrated at the base of the cavity membrane system.
✅ 𝗣𝗶𝗽𝗲𝘄𝗼𝗿𝗸 𝗰𝗮𝘀𝘁 𝗶𝗻𝘁𝗼 𝘁𝗵𝗲 𝘀𝗹𝗮𝗯 designed with sufficient fall to ensure continuous flow.
✅ 𝗔 𝗻𝗼𝗻-𝗿𝗲𝘁𝘂𝗿𝗻 𝘃𝗮𝗹𝘃𝗲 fitted to prevent any risk of backflow from the external surface water system.

Gravity-fed systems are highly effective where site levels allow, offering a low-maintenance, energy-free solution for managing groundwater ingress.
We’re proud to support projects that combine modern construction with heritage sensitivity—delivering long-term protection and peace of mind.

🔹Cambridge House Walkthrough Video

🎥 Take a behind-the-scenes look at our installation work on the prestigious Cambridge House renovation project!

This video captures just a glimpse of the scale and complexity involved in transforming this iconic London landmark into a luxury 5-star hotel. With multiple phases and intricate detailing, it’s a project that demands precision, expertise, and collaboration—and we’re incredibly proud to be part of it.

From heritage preservation to cutting-edge waterproofing solutions, our team has been working closely with contractors and consultants to ensure the highest standards are met at every stage.

How To Prevent Basement Waterproofing Failures

June 2025 Newsletter

Basement waterproofing failures cost the UK construction industry millions of pounds every year—not just in repairs, but in project delays, reputational damage, and client dissatisfaction. The most frustrating part? These failures are entirely preventable.

At MacLennan, we’ve spent decades refining our approach to waterproofing design, installation, and maintenance. In this post, we’ll explain how we prevent failures before they happen—and why our systems are trusted across the UK and beyond.

KC4 Lots Road Case Study road lift before after

KC4 KC4 Lots Road Case Study Road Case Study 17

May Newlsetter - 9 Partridge Walk - 10.05.2024 JH

✅ It All Starts with Smart Design

Most waterproofing failures can be traced back to one root cause: poor design. At MacLennan, we believe that good design is the foundation of waterproofing success. But we’re not just talking about detailing—we mean integrating the installation process, maintenance strategy, and repairability into the design from day one.

The British Standard and all major codes of practice are clear: waterproofing systems must be designed with repair and maintenance in mind. Yet, many systems are installed without any consideration for how they’ll be accessed or serviced once finishes are in place.

🧱 Why Type C Systems Are the Gold Standard

If your basement includes finishes, internal walls, or linings, then only a Type C cavity drain system can provide the level of repairability required for long-term performance.

Unlike other systems, Type C solutions are designed to manage water ingress by directing it to a controlled drainage system. But even these systems can fail—if they’re not properly maintained.

🔍 Inspection & Servicing: The MacLennan Difference

Most service providers focus on pump maintenance, but the real Achilles heel of a cavity drain system is the drainage channel. If this becomes blocked or compromised, the entire system is at risk. At MacLennan, we’ve solved this with:

We design and manufacture our own inspection ports, allowing directional camera access for full visibility.
We commission and inspect the system after finishes are installed—when many issues first appear.
We provide ongoing servicing through our dedicated in-house team, ensuring long-term performance.

📡 Remote Monitoring & Superyacht-Grade Reliability

We’ve taken it a step further with remote monitoring technology built into our systems. This allows us to track performance in real time and alert clients to potential issues before they become problems.

And when it comes to power reliability, we use state-of-the-art battery backups and inverters—the same systems trusted on ocean-going superyachts. These can even be upgraded to power essential services during outages.

🛠️ Servicing Is Not Optional—It’s Essential

You wouldn’t buy a car and never service it. A waterproofing system is no different. Regular maintenance is the key to preventing failures, and it should be built into the design from the start.

At MacLennan, we don’t just install systems—we design them for life.

💬 Want to Learn More?

We’re passionate about helping clients avoid costly waterproofing failures. If you’re planning a basement project or want to ensure your current system is protected for the long haul, get in touch with our team.

Contact us

MAY Social Media Post Roundup

This month, our team has been busy delivering expert waterproofing and damp proofing solutions across the UK and beyond. Here's a quick look at what we’ve been up to:

🔹 Guernsey Waterproofing Installation
We brought our specialist waterproofing expertise to the Channel Islands, ensuring a robust and long-lasting solution for a coastal project in Guernsey.

This unique private dwelling is ingeniously built into a sloping hill and features a semi-basement. The project presents several challenging details, but our team's expertise shines through. ✨ After meticulously reviewing the architect's drawings, our senior surveyor has designed a state-of-the-art waterproofing system that fully complies with British Standards BS8102:2022. This system incorporates two forms of waterproofing to ensure the highest level of protection.

🔹 Deck Waterproofing in London
In the heart of the capital, we completed a deck waterproofing project designed to protect the basement built below from water ingress.

This ambitious project involved the demolition of an existing dwelling and the construction of a brand-new property, featuring a double-storey basement and four upper levels. The double basement is equipped with luxurious amenities, including a spa, gymnasium, treatment room, kitchen, and staff areas

🔹 Barn Conversion in Swindon
Our damp proofing installation played a key role in transforming a historic barn into a dry, habitable space—blending heritage with modern performance.

Barn and stable conversions are popular for their stunning architecture. By taking a sensitive design approach, we preserve their original charm while transforming them into cosy living spaces. 🛋️ Skilled waterproofing is crucial to keep interiors warm and dry, protecting your décor from dampness.