Built Environment Archives - Hawkins Forensic Investigation

Congratulations to Anna Hodkinson on Outstanding Academic Achievement

Chloe Duggan — Wed, 29 Jul 2026 09:52:19 +0000

Hawkins is delighted to congratulate Anna Hodkinson of Morham + Brotchie on her exceptional academic success, having achieved a First-Class Honours degree in Quantity Surveying from the University of Central Lancashire.

Anna’s achievement is particularly impressive, having attained an outstanding overall result during her degree studies. Since joining Morham + Brotchie in 2025, following her transfer from A. Lamb Associates, Anna has become a valued member of the team and has quickly established herself as a highly regarded member of the wider Hawkins Group.

Adding to this success, Anna has been awarded the prestigious CIOB Certificate of Excellence by the Chartered Institute of Building (CIOB). The award recognises the student who achieves the highest mark on their CIOB-accredited degree programme, making this an outstanding accolade within the construction and quantity surveying profession.

In a letter from the CIOB, Rosalind Thorpe, Director of Education and Standards, said:

“On behalf of the Chartered Institute of Building, I would like to offer my sincere congratulations on being awarded the CIOB Certificate of Excellence in recognition of achieving the highest mark on your degree course. This is an outstanding achievement and the Chartered Institute of Building is delighted and honoured to be able to present you with this award.”

The letter goes on to recognise Anna’s accomplishment and wishes her continued success as she progresses in her career.

Anna’s academic success and industry recognition are a testament to her hard work and determination. Everyone at Morham & Brotchie and across the Hawkins Group is incredibly proud of her achievements and looks forward to seeing her continue to excel throughout her career in quantity surveying.

Congratulations, Anna, on this remarkable achievement and well-deserved recognition. We wish you every success in the future.

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Richard Keightley Highlights Rising Complexity of Flood Insurance Claims

Chloe Duggan — Wed, 22 Jul 2026 10:15:20 +0000

Forensic Hydrologist Richard Keightley was invited as a guest presenter by global law firm Kennedys to share his expertise on the growing complexity of flood-related insurance claims in a changing climate in their Property Damage webinar.

Joining Kennedys’ Adam Blanchard and Tara Mukerji, Richard explored how climate change is reshaping the risk landscape, driving an increase in weather-related claims, higher costs, and mounting challenges around insurability and resilience across the insurance and property sectors.

His presentation provided an expert overview of the key causes of flood claims, from extreme weather events to drainage failures, infrastructure issues, and design or construction defects, highlighting how multiple factors often combine to cause losses. He emphasised that as severe weather events become more frequent, many incidents may no longer be attributable to third-party fault, making liability assessments more complex.

Richard also outlined the importance of detailed technical investigations in distinguishing between natural events and human or operational failures, using hydrological data, modelling, and site analysis to support or defend claims.

The session offered practical insight into the evolving challenges facing insurers and legal professionals as they respond to increasingly complex flood risks in a climate-affected world.

Richard Keightley is a Chartered Water and Environmental Manager and Chartered Environmentalist. He specialises in the investigation of flooding, water ingress and drainage issues, and has provided CPR-35 expert witness evidence in civil claims for both claimants and defendants. Richard joined Hawkins in 2017 as part of our civil engineering team, having previously worked at two major engineering consultancies, a water and sewerage company, and New Zealand’s National Institute of Water and Atmospheric Research.

Or read one of Richard’s previous Insight articles on the subject: Basement Drainage Failures: Forensic Insights

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Stormwater Management on Bridges

Chloe Duggan — Sun, 19 Jul 2026 18:36:51 +0000

Bridges play a vital role in our daily lives by connecting areas separated by natural or man-made barriers, enabling efficient transportation and access. China has over 1 million bridges (CEIC, 2023), and Hong Kong alone currently has 1475 flyovers and road bridges (Highways Department, 2025). Each bridge contributes to ensuring smooth traffic flow and supporting daily commutes.

Bridges are typically designed to last more than 100 years; therefore, ensuring long-term performance is critical. Every year, billions of dollars are allocated to maintaining bridges worldwide and this figure is expected to rise as new bridges are constructed and existing ones age. A well-designed and properly maintained bridge will contribute to both its durability and reduced maintenance costs.

Among the many aspects of a bridge structure, stormwater management is particularly crucial. Poorly designed, installed, or maintained drainage systems can lead to water accumulation in undesirable areas, accelerating the deterioration of structural components and creating safety hazards for users and the surrounding environment, as shown in Figure 1. Effective drainage design and maintenance not only extend a bridge’s lifespan, but also reduce overall operational costs and improve safety.

This article provides an overview of stormwater management in bridge structures, with a particular focus on surface runoff control in concrete bridges and its role in ensuring structural safety and long-term durability. References to established design standards, including the UK’s Design Manual for Roads and Bridges (DMRB) and the Hong Kong Structures Design Manual 2013 (HKSDM2013), are included where applicable to illustrate best practices and regulatory guidance.

Discussion

Stormwater on a bridge is generally managed through four key methods: Structural Elements, Deck Drainage, Waterproofing Membranes, and Watertight Joints.

1. Structural Design

During the design stage, structural engineers and architects have the opportunity to incorporate strategies into the bridge geometry, surface shaping, and reinforcement detailing to minimise stormwater accumulation, often at little or no additional cost.

> Bridge geometry should ideally prevent standing water or ponding by incorporated appropriate longitudinal and transverse deck gradients. The UK’s DMRB-CD358 recommends a minimum longitudinal gradient of 1:100. Unfavourable geometries, such as vertical sags (Figure 2), can lead to water accumulation and should be avoided whenever possible. Where they are unavoidable, special attention to drainage and detailing is required.

> Structural shape plays a key role in stormwater management. Sloping the surface finish, such as on the bridge deck and bearing seat areas, helps prevent standing water by allowing it to flow naturally out of the horizontal surface towards designated drainage points. Drip edges and grooves are also important, as they help direct water away from structural surfaces. HKSDM2013 provides visual examples of both effective and poor practices for designing drip edges and grooves (see Figure 3). Any gaps exposed to stormwater should be avoided or properly sealed.

> Reinforcement detailing: Design codes and standards typically require crack width calculation to ensure that the size, number, and spacing of reinforcement bars are appropriate. This helps prevent excessive cracking from forming during the service, which could otherwise allow water to penetrate the concrete more rapidly and accelerate deterioration.

2. Deck Drainage

The deck drainage system consists of the intake, the drainpipes, and the outlet. Stormwater enters through the intake and is delivered through the drainpipes all the way to the outlet, where it connects to a local drainage system or natural water body. Poor design and maintenance can lead to several problems:

> Inadequate drainage design: Insufficient drainage capacity can lead to water build-up during heavy rainfall, leading to overflow into unwanted areas. This creates hazards for users and the surrounding environment. Incorporating drainage design from the early stages of bridge design is essential to achieve effective drainage.

> Blockages: Debris carried by stormwater can cause blockages, so drainage systems should be designed for ease of maintenance. Regular inspection routines are also crucial to ensure issues are identified and resolved promptly.

> Unsuitable materials: The material chosen should be durable and require minimal maintenance. Design codes often specify suitable material types. For example, HKSDM2013 requires the use of Unplasticized Polyvinyl Chloride (uPVC) for drainpipes in Hong Kong.

3. Waterproofing Membrane

A waterproofing membrane is an additional impervious layer, typically made of bitumen, polymer, or cementitious materials, applied over the bridge deck to prevent direct water ingress. Selecting the appropriate material for each specific project is crucial to ensure effective waterproofing.

These membranes can be applied in different forms, such as liquid, sheet, or spray. It is essential to adhere to relevant design codes when applying waterproofing to ensure long term effectiveness. Improper application can lead to issues such as insufficient bond strength, leakage due to poor detailing, and damage due to construction activities.

4. Watertight Joint

In modern bridge design, continuous bridges are increasingly favoured over simply supported designs. This shift is largely due to the risks associated with bridge joints, which are prone to leakage, deterioration, and high maintenance demands. Modern design codes such as HKSDM2013 and DMRB CD350 include clauses encouraging designers to minimise joints wherever feasible.

In certain circumstances, joints might be unavoidable, for example monolithic connection at abutments or when connecting new structures to existing ones. Such cases present their own challenges, and using a movement joint can be a safer and more economical design choice. In these cases, joints must be fully watertight, and access for maintenance must be considered in the joint design.
Joint watertightness can be achieved through, proprietary watertight movement joints or integrating drainage systems within the joint. If joints are not watertight, accumulated water can lead to:

Role of Technology in Bridge Drainage Maintenance

Maintaining drainage systems on bridges can be labour and cost intensive, especially for long bridges spanning challenging terrains such as seas or valleys. The use of modern technologies can improve safety, enhance maintenance quality, and reduce operational costs. For example, CCTV cameras installed on bridges allow personnel to inspect drainage inlets and identify surface blockages or flooding without the need of road closures or traffic diversions. Drones and drain inspection cameras (Figure 7) can inspect hard-to-reach locations, such as drainpipes running at the underside of the bridge. Various sensors (flow, pressure, moisture, etc.) combined with artificial intelligence have the potential to support real-time monitoring, early detection of anomalies, and predictive maintenance planning. These approaches reduce the likelihood of sudden failures and help maintenance teams respond proactively.

Final Remarks

Stormwater management on bridges is a well-established aspect of bridge design, addressed by various design standards such as HKSDM2013 and DMRB. Adhering to these guidelines when designing both the structure and the drainage system results in more durable, reliable and cost effective bridges. In summary, stormwater management on bridge is achieved through:

Structural design: bridge geometry, element shape, and reinforcement detailing.
Good deck drainage system design and maintenance.
Application of appropriate waterproofing membranes.
Provision of watertight joints and minimisation of joints where possible.

Technologies such as CCTVs, drones, inspection cameras, and smart sensors powered by AI are increasingly important for improving the safety, quality, and cost-effectiveness of bridge drainage maintenance. These tools enable remote inspections, real-time monitoring, and predictive analysis making them particularly valuable for long bridges spanning challenging terrains.

About the Author

Eng Phin is a structural engineer with over 10 years of experience in bridge and building design. He began his career in Indonesia, contributing to major bridge projects such as the Semanggi Interchange Upgrade and Kualanamu Light Rail Transit system. His expertise spans modern bridge construction methods, temporary works, and post-tensioning.

He has since worked on international projects in Hong Kong and beyond, applying local and global design standards while promoting digital engineering in structural design.

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Bernard Travers Celebrates 10 Years with Hawkins

Chloe Duggan — Wed, 08 Jul 2026 10:16:35 +0000

This month, we are delighted to celebrate Bernard Travers as he marks 10 years of dedicated service with Hawkins. A Chartered Engineer and Member of the Institution of Civil Engineers, Bernard joined Hawkins in 2016, bringing specialist civil engineering expertise to the business and helping to strengthen our Built Environment offering. Since then, he has investigated more than 250 cases involving civil, structural and building-related failures, developing particular expertise in basement water ingress, building collapses, glazing failures, cladding defects, storm and vibration damage, solar panel installations and roofing issues. He also advises on Building Regulations and design standards, combining engineering analysis, testing and practical investigation to help clients understand complex failures.

Bernard graduated from the University of Cambridge in 2010 with a degree in Engineering, specialising in Civil, Structural and Environmental Engineering. During his studies, he was sponsored by Skanska UK, gaining hands-on experience on highways and rail projects. Alongside his technical expertise, Bernard has a passion for making engineering accessible and engaging. In 2017, he won the Institution of Civil Engineers’ Pitch 180 competition by explaining subsidence in just 180 seconds using confectionery.

As Bernard reaches a decade with Hawkins, we caught up with him to reflect on his journey so far:

What brought you to Hawkins?

I first tried investigating building defects in my previous role and enjoyed the challenge of approaching problems in a different way to typical design. Instead of asking, ‘What is the right way to stop these kinds of problems?’, I was asking, ‘How exactly did this building go wrong?’

I wasn’t aware of forensic firms like Hawkins, so when I found out what a job at Hawkins would involve, I jumped at the chance!

How has your role evolved over the last 10 years?

I started alongside two other new civil engineers, bringing the Built Environment team to a total of six investigators. Since then, many more people from a wide range of disciplines have joined the team – I think we total over 40 built environment investigators now, not to mention the Quantity Surveyors from ALA and M+BP that joined the Hawkins Group last year.

As a result, I now spend more time answering questions and supporting others than I did when I first joined. I still seem to have just as much to learn from others, but now it’s more of a two-way street.

What’s one of the biggest lessons you’ve learned?

Knowledge and training are useful, but nothing can replace getting to site and collecting physical and witness evidence first-hand.

When I started, my first instinct was to go from the initial papers straight to my calculator, pen and paper, and formulae. Now, I always prefer to start with a site visit and witness interviews.

What do you enjoy most about your current role?

Finding a clear answer to a case that starts with apparent puzzles and contradictions.

Looking back, what’s your favourite team memory?

The London Office Christmas parties in the first few years after I started. The team was smaller then and many people brought their partners. It was a real joy to see people from all different walks of life bonding over having slightly obsessive, nerdy engineering types for partners – and the familiarity of the blue four-colour Hawkins pen!

Who has inspired or mentored you during your time at Hawkins?

Too many people to mention!

Ian Major took me on some of my first site visits, including a particularly memorable first site visit to a scene where there had sadly been multiple fatalities. He helped me tame my writing style to be more focused.

Helen Rosser took me on a few fire investigations when I started. The discipline was so alien to me, but seeing the way that Helen worked opened my eyes to the value of site investigations and witness interviews, especially in the midst of what seemed to me chaotic and unintuitive scenes, where the key witnesses were quite often (and quite understandably) very shaken by recent events. Seeing the work that she and the other fire investigators did brought home why quick, clear investigation and reporting was so important: it lets people get on with their lives after a big incident.

Peter Reupke has always been on hand to help with experience and guidance. When I feel I have ‘got lost in the woods for the trees’ on a particularly knotty technical matter, or that I am going round in circles on a client’s question, he always seems to have either a similar experience or to know the right questions to help cut to the crucial point.

What advice would you give to someone just starting at Hawkins?

Don’t let what you know get in the way of discovering and explaining what matters.

What keeps you motivated after 10 years?

Every case has some new aspect that requires really deep thinking. It’s a pleasure to do that alongside so many engineers and scientists that I truly respect.

Over the past decade, Bernard has made a significant contribution to Hawkins, not only through his technical expertise and the hundreds of investigations he has undertaken, but also through his willingness to support colleagues, share knowledge and help develop the next generation of investigators. His curiosity, analytical mindset and commitment to uncovering the facts behind complex failures continue to embody the values that make Hawkins successful.

Congratulations, Bernard, on reaching your 10-year anniversary, and thank you for everything you have contributed to Hawkins. We look forward to seeing what the next decade brings.

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Hawkins & A Lamb Associates Host Summer Boat Party on Lake Windermere

Chloe Duggan — Tue, 30 Jun 2026 16:29:51 +0000

Hawkins and A Lamb Associates (ALA) recently welcomed clients, colleagues and guests to their Summer Boat Party on the iconic Lake Windermere.

The event marked both ALA’s continued success and the one-year anniversary of them joining the Hawkins group. This milestone reflects the successful integration of complementary expertise, strengthening Hawkins’ combined quantum, delay and forensic service offering.

Guests gathered at the Belsfield Hotel in Bowness, where the evening began with a relaxed drinks reception overlooking the lake. From there, attendees enjoyed a stroll through the hotel’s gardens to the shoreline, where a privately chartered steamer awaited.

Boarding a classic 1930s vessel, guests enjoyed a leisurely cruise across Windermere. The evening featured live music, freshly prepared food and an open bar, providing a vibrant yet relaxed setting for networking as the boat sailed through the heart of the Lake District.

The event built on the success of previous gatherings, bringing together a diverse mix of clients and industry professionals. It provided an opportunity not only to reconnect, but also to celebrate the collaboration between Hawkins and ALA, and to thank clients for their continued support.

Tom Lamb, Director at ALA commented: “While we were perhaps lucky with the weather, the real reason the event was such a success was our clients. Thank you all for making the evening uniquely ALA – fun and relaxed, yet business-focused too. The great mix of attendees led to some really interesting conversations.”

With strong attendance and very positive feedback, the event highlighted the importance of building connections, and reinforces Hawkins’ and ALA’s commitment to collaboration and client engagement.

Visit the Hawkins Events page to view upcoming events, and register for CPD sessions and drinks receptions taking place in Belfast and London.

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Meet Yvonne Ainsworth: Geotechnical Engineer

Chloe Duggan — Tue, 23 Jun 2026 08:28:16 +0000

Yvonne joined Hawkins in December 2025 as a Principal Associate, bringing expertise in geotechnical engineering. She is a Chartered Civil Engineer and Fellow of the Institution of Civil Engineers (ICE), with extensive leadership experience across major infrastructure and energy projects. Her background combines technical expertise in geotechnical design and construction, with senior roles in operational management, risk, and HSEQ.

After graduating with a first-class degree in Civil and Structural Engineering from RWTH Aachen University, Yvonne began her career with WS Atkins before moving into specialist piling and geotechnical contracting. She delivered complex foundation and retaining wall projects, including Battersea Power Station and major Crossrail stations, and became a recognised authority in piling and diaphragm walling for high-risk schemes, both in the UK and internationally.

Yvonne later progressed into Director roles, overseeing geotechnical solutions for Energy from Waste and renewable energy projects. She then became Managing Director (Onshore) and subsequently Business Unit Director for Taylor Woodrow’s South Region, where she led a £40m portfolio and a multidisciplinary team.

We spent some time with Yvonne to learn more about her career journey and what brought her to Hawkins.

Tell us a bit about your background and your role at Hawkins

I have always been intrigued by how things work. During my Erasmus year in 1998/99, which I spent at Sheffield University, I learnt about geotechnical engineering, and it has fascinated me ever since. My degree was highly theoretical, so when I started my career, consultancy was the obvious choice. However, I soon realised that I didn’t fully understand how things were built. My employer gave me the opportunity to spend some time on site, and I truly fell in love with it. Having to make decisions quickly, often with limited information available was extremely exciting and rewarding. From that point on, I spent most of my career in construction.

I have now joined the geotechnical team at Hawkins, and am looking forward to broadening my experience into the wider civil and structural engineering world.

What motivated you to become a forensic investigator?

For as long as I can remember, I have approached problems with a forensic mindset. I have always been excited about uncovering what really happened when things go wrong, even though I have spent the majority of my career planning to prevent those situations in the first place. Before joining Hawkins, I was often sent to site to ‘figure out’ what was going wrong, whether this was operational, commercial or technical. This was arguably the most enjoyable part of my job, so the move to become a forensic investigator is probably not as big a change as it looks on paper.

What drew you to Geotechnical Engineering?

Geotechnics has always fascinated me because soil doesn’t behave like other engineering materials, it’s far less predictable. What you do to the ground in one area of site, is most likely producing a completely different response somewhere else. In addition to that, a lot of the work in geotechnics takes place below ground, such as piling, tunnelling or ground anchors, so you can’t directly observe it. As a geotechnical engineer, you rely on your experience, knowledge and a decent amount of intuition. I think that’s a great combination!

“For as long as I can remember, I have approached problems with a forensic mindset. I have always been excited about uncovering what really happened when things go wrong.”

What attributes do you consider important for a successful forensic investigation career?

Attention to detail, as well as logical and analytical thinking. Without those, you are unlikely to get to the bottom of what happened.

What’s the most interesting case that you have worked on?

I was once sent to Montreal, Canada, to help understand why the tendered drilling outputs were not being achieved as expected, and whether this was due to a change in ground conditions. Working in -35°C, surrounded by snow and ice, whilst observing the activities on site, was certainly an experience. What made this case particularly interesting was the combination geology, the effect of low temperatures, human behaviours and logistics. And I have never been to site with heated Portaloos since…

What do you love most about what you do?

I love being a geotechnical engineer. Solving problems or figuring out what went wrong is simply the icing on the cake. The most rewarding part is figuring out what happened and then someone else coming to the same conclusion. I love that I don’t consider my job as something I have to do, but rather something that I want to do. I’m excited that every day brings a new challenge or opportunity. It’s never boring or predictable!

What business advice would you give to your younger self?

Be patient. Good things sometimes take time.

Whilst I have become a lot more patient since having children (and probably with age) it’s still not my strong point. I often have to remind myself that some things simply need time. This is equally good advice when working with people: some people will be with you immediately, while others need time to take things in and digest the information. Be patient in your approach, don’t rush.

“I love being a geotechnical engineer. Solving problems or figuring out what went wrong is simply the icing on the cake.“

Do you have a favourite app, gadget or tool

I don’t have a favourite app, gadget or tool that I rely on for work, but I often go for a long walk or run to think things through in my head and evaluate different scenarios. Finding the root cause of an issue, often takes time and consideration, something that I find best done away from a desk.

What are the biggest challenges in the industry?

The biggest challenge in the industry is the skills shortage. Engineering, especially geotechnical engineering, is becoming less and less popular, and universities are struggling to fill available spaces. At the same time, the industry is losing a lot of experience through retirement or people leaving the profession at mid-career stage.

Another challenge is the mindset around learning. Too often I hear people say, ‘Oh, I did that 3 years ago, I can’t remember now.’ Learning shouldn’t be just about passing an exam, it needs to be continuous and long-term. Understanding the fundamental principles of engineering is vital as a forensic investigator.

Where do you see the industry evolving in the future?

I can see that technology and digitalisation will play an ever-increasing part in the way we build, and therefore in the way things will go wrong. But new technologies will also create opportunities for forensic investigation, whether through the speed with which we access information, improved analysis tools, or new ways of interacting with others and examining scenes. We need to embrace the technological advances and use them to our benefit.

What differentiates Hawkins from other forensic investigation/consultancy firms?

From my experience so far, the biggest difference is the level of investment in staff development. Training is given the top priority, and all aspects of the business contribute to it. I also have to say that everything is much more organised here than any other business I have worked for in the past.

“I can see that technology and digitalisation will play an ever-increasing part in the way we build, and therefore in the way things will go wrong...We need to embrace the technological advances and use them to our benefit.“

Tell us something about yourself outside of work

Apart from the fact that I am German, which, with a name of Yvonne Ainsworth, is not that obvious, I like to stay active. I enjoy going to the gym, playing pickle ball or taking the dog for a walk. I also used to be qualified football referee and once officiated an U18 Arsenal match, and I now coach my daughter in her refereeing career.

What’s something you have done, but will never do again?

Sky diving. I’ve always said I try everything once, but I hated every second of it and screamed the entire way down.

What is your guilty pleasure?

Having a mid-afternoon snooze at the weekend.

Do you have a hidden talent?

People often say I have a crystal ball to predict the future (and no, I can’t tell you the lottery numbers). I call it intuition and gut feel.

What is the top destination on your must-visit list and why?

I have been fortunate enough to visit my must-see destinations. In my thirties, and before having children, I took a year out to travel the world. I visited India, Nepal, Southeast Asia, and Australia. I’ve always loved travelling and experiencing other cultures. I have also been to New Zealand, most of Europe, America and Canada. Africa and South America are still on my bucket list.

What is one song you have completely memorised?

Hakuna Matata from The Lion King. Don’t ask me why.

If you would like Yvonne or another Hawkins expert from another discipline to investigate a case or present to your organisation, please contact us.

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Acoustic Design In School Buildings

Chloe Duggan — Mon, 22 Jun 2026 08:02:35 +0000

Acoustics is an important factor to consider when designing school buildings, because it affects the quality of communication and learning in classrooms and other spaces. Poor acoustics can make it difficult for students and teachers to hear and understand each other, leading to frustration, fatigue, stress, and reduced academic performance. Good acoustics can enhance speech clarity and create a comfortable and productive learning environment.

The UK Department of Education published the Acoustic Design of Schools: Performance Standards, Building Bulletin 93, in 2014. This set out the requirements for indoor ambient noise levels, reverberation times, and sound insulation for new and refurbished school buildings. These requirements are also linked to the Building Regulations, the School Premises Regulations, and the Independent School Standards.

One of the main factors affecting classroom acoustics is the indoor ambient noise level, which is the sound level in the room when no one is speaking. This noise can originate from external sources, such as traffic, construction, or playgrounds, as well as internal sources, such as ventilation, heating and cooling systems, or other equipment. High indoor ambient noise levels can mask or interfere with the speech signal, making it harder for listeners to hear and comprehend what is being said. Low indoor ambient noise levels can allow quiet, yet audible, disturbances to be far more distracting than they usually would be. This can affect the ability of students to follow instructions, participate in discussions, and concentrate on their work.

Another factor that affects the acoustics of a classroom is the reverberation time of the space. In layman’s terms, it is the ‘echo’ in a room, but technically, it is defined as the time it takes for an impulsive sound (such as a hand clap or a balloon burst) to decay by 60 decibels. Reverberation is caused by sound reflecting off the room’s surfaces, such as walls, ceilings, floors, or furniture. Reverberation targets vary depending on the type of room and activity planned for the room. For instance, a piano rehearsal music room will not have the same requirements as a classroom, and a dining hall will not have the same requirements as an assembly hall. This is because reverberation can be detrimental to speech, especially in large or crowded rooms, but is not necessarily detrimental to music in the same way. Long reverberation times can make speech sound muffled, distorted, or ‘echoey’, reducing its intelligibility and increasing the listening effort. It can also affect the vocal health of teachers, who may have to strain their voices to speak louder or more clearly. This can affect students’ learning outcomes, especially those with hearing impairments, language difficulties, or special educational needs (SEND).

Acoustics is especially important for the design of SEND schools because many students have hearing or communication challenges, or other conditions that affect their listening and learning abilities. According to the 2010 Equality Act, all schools have a responsibility to improve their accessibility plans for pupils and staff, and this includes providing optimal acoustic conditions.

Some of the strategies that acoustic engineers can use to improve the acoustics of schools include:

Choosing a suitable location and orientation for the school building, away from noisy sources or facing away from them to minimise the impact of external noise on the school environment
DevelopmentUsing sound-absorbing materials and finishes, such as acoustic tiles, panels, or carpets, to reduce reverberation s that could be affected by sources of flooding other than rivers and the sea (for example surface water, sewers, groundwater and infrastructure failure)
Installing sound-insulating materials and structures, such as double-glazed windows, doors, or walls, to block or reduce external or internal noise
Making use of acoustic barriers or screens, such as fences, hedges, or walls, to deflect or attenuate noise from outside or inside the school
Using acoustic baffles or diffusers, such as suspended ceilings, shelves, or furniture, to scatter or redirect sound waves and improve sound distribution
Ensuring mechanical ventilation, heating, and cooling systems are quiet, well-maintained, and are acoustically treated
Using sound amplification or enhancement systems, such as microphones, speakers, or hearing loops, to improve the speech-to-noise ratio and the audibility of speech. These systems can amplify the speaker’s voice and deliver it directly to the listener, or to a hearing aid or cochlear implant.

Given the propensity to affect the quality of communication and learning in classrooms and other spaces, acoustic consideration is an essential aspect of the design of schools.

By applying the principles and practices of acoustics, acoustic engineers play an instrumental role in creating school buildings that provide optimal teaching and learning conditions for teachers and students.

If you have an acoustical related issue and need the services of our Acoustics Consultancy team, please contact us.

References

Equality Act 2010 – https://www.legislation.gov.uk/ukpga/2010/15/part/6

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Hawkins Experts Present at Crawfords MCL Surveyors Technical Forum

Chloe Duggan — Thu, 11 Jun 2026 15:58:46 +0000

Hawkins Built Environment experts recently delivered a presentation at the Crawfords MCL Surveyors Technical Forum, providing attendees with a detailed look at the forensic investigation of property damage claims linked to extreme weather and structural loading.

The session was led by Jamie Paterson, Jack Allison and Simon Bateman, who shared their combined expertise through a series of case studies examining storm-related damage, snow loading, and subsidence.

The presentation explored how forensic engineering principles are applied to determine the root cause of structural failures, with particular emphasis on distinguishing between sudden, insurable events and gradual deterioration. Using real-world examples, they demonstrated how factors such as snow loads, wind forces, water ingress, and pre-existing defects can interact to compromise buildings in complex insurance claims.

Jamie explored cases involving snow loading, highlighting the challenges in assessing claims where data may be limited and conditions vary significantly. He emphasised the importance of comparing observed conditions against design standards and assessing whether structural capacity may have been reduced over time due to maintenance issues or degradation.

Simon presented case studies on storm damage and rainwater ingress, illustrating how detailed investigations, often incorporating historical records, site inspections and aerial imagery, can reveal whether weather events alone were responsible or whether underlying weaknesses in the structure played a key role.

Jack concluded with a subsidence-focused case study, demonstrating how forensic analysis can establish the timing and progression of damage, which is critical when determining policy response. His presentation highlighted the importance of historical evidence and site conditions in distinguishing between ongoing ground movement and newly occurring damage.

A consistent theme throughout the session was that successful claims investigation relies on a thorough understanding of both external forces and the internal structural condition, alongside the ability to interpret multiple sources of evidence. The forum provided an opportunity for surveyors and insurance professionals to gain practical insight into how forensic investigations support decision-making in complex claims.

If you would like one of our experts to investigate a case or present to your organisation, please contact us.

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Secant Pile Walls & Basement Excavations: What Could Possibly Go Wrong?

Chloe Duggan — Mon, 08 Jun 2026 08:05:43 +0000

Basements are now routine in urban developments – from plant rooms and car parks to premium residential space. Yet “routine” should not be confused with “simple”. Underground works introduce a unique set of construction risks, which, if not properly managed, can lead to significant issues, increased costs and programme delays. When properly executed, these works enable the construction of challenging basements, even on constrained sites and in areas with high groundwater tables.

Many properties now require basement construction. In most cases, this is achieved using embedded retaining walls, especially in places with limited space with each option. Where groundwater is present, an embedded retaining wall type must be chosen that can retain the groundwater. Sheet pile, secant pile or diaphragm walls are feasible options. CIRIA C760 ‘Guidance on embedded retaining wall design’ provides selection guidance across wall types.

Secant pile walls, in particular, are widely used because they provide support in both temporary and permanent conditions and can be adapted to suit challenging sites. They retain ground and groundwater, minimise ground movement and can carry substantial vertical loads.

Basements may be routine, but they are not simple. Poor planning and/or execution can lead to significant technical issues, cost overruns, and programme delays. Due to their frequent use, this article focuses on secant pile walls – their role, what can be expected of them and the common issues associated with their design and construction.

What is a Secant Pile Wall?

A secant pile wall is a continuous wall formed by interlocking bored piles, as shown in Figure 1.

Primary piles, often referred to as female piles, are installed first, and secondary piles, also known as male piles, are drilled so that each one cuts into the adjacent primaries, creating an interlocking line of concrete. Primary piles are typically unreinforced (see Figure 2).

This system of interlocking primary and secondary piles creates a hard/soft or hard/firm secant wall. The difference between the two wall types is the concrete strength in the primary piles. If the secant wall is used as temporary works only, there is no need for durability or strength requirements for the unreinforced pile, and non-structural concrete may be used. Due to advances in rig power and the cost of using secant walls as temporary works only, hard/soft secant walls have become less common compared with hard/firm secant walls where the primary pile often consists of a low-grade structural concrete, such as a C8/10.

However, in very deep excavations and in response to additional structural requirements, it may be necessary to also reinforce the female piles (see Figure 3). This combination then becomes a hard/hard secant wall which uses high grade structural concrete in both primary and secondary piles.

Secant walls can be constructed using various techniques:

The choice of technique depends on the project requirements, especially permissible tolerances, retained height, depth of interlock required and prevailing ground conditions, see Figure 4. Interlock is the length of wall over which the secondary piles cut into the primary piles. This distance is of particular importance for groundwater exclusion.

Achievable tolerances and typical depth of interlock are defined in the ICE Specification for Embedded Retaining Walls (ICE SPERW) in Table B1.4 and partially reproduced below in Table 1. Whilst the verticality of wall and depth of achievable interlock increase from CFA towards RBP, so does the cost, complexity and the timeframe to install the secant wall.

Advantages of Secant Pile Walls

There are numerous reasons why secant pile walls are often the preferred solution for basement construction:

1. Space Efficiency in Constrained Sites

Urban basements are frequently built tight against property boundaries or adjacent structures. This makes secant walls ideal for city-centre projects where every metre counts.

2. Groundwater Management

Secant walls provide an effective horizontal water barrier when installed correctly. This is particularly valuable where high water tables or sensitive neighbouring assets are present. However, they do not necessarily mitigate vertical groundwater flow into the excavation and should be used in conjunction with a groundwater management strategy (CIRIA C750 ‘Groundwater control: design and practice’).

3. Structural Versatility

Secant walls can serve both as temporary excavation support and as part of the permanent basement structure, reducing duplication of work. They can be designed to carry substantial loads, making them suitable for deep basements and complex load cases.

4. Adaptability

Secant pile walls can be constructed using a variety of piling techniques to address a range of retained heights, tolerance requirements and ground conditions. Secant walls can also adapt to accommodate many footprint shapes. This flexibility makes secant walls a practical choice for many UK ground profiles.

Where Things go Wrong

On paper, secant pile walls look like the perfect solution: strong, versatile, and great for tight sites. But in the real world, things do not always go to plan. Here are the most common issues we see and why they matter.

Misalignement

Secant walls depend on the interlock between primary and secondary piles. However, piles (typically secondary piles) can become misaligned for a variety of reasons, see Figure 5.

Some common root causes for misalignment are given below:

> Primary concrete too hard, causing the secondary pile to deviate into ‘softer’ soil. This is often caused by inadequate or untested concrete mix design and is most commonly seen in CFA walls.

> Incorrect sequencing. Sequencing is of particular importance in CFA secant walls. If the sequence is not planned properly, or disrupted due to site changes or plant breakdowns, the concrete in the primary piles may become too hard, resulting in the defect described above.

> Incorrect technique chosen for interlock requirements. Due to the significant increase in costs from CFA to CCFA and RBP, the interlock limits of CFA are frequently pushed. Joints, especially in standard CFA augers, create a degree of flexibility and make it easier for piles to deviate from the vertical. To minimise this risk, having fewer joints in the auger is better.

> Obstructions in the ground, either natural (such as boulders) or man-made (in the form of old foundations or walls etc.), can cause piles to deviate from their intended position and verticality. RBP techniques are best placed to deal with obstructions in the secant wall alignment and should be chosen if obstructions cannot be removed prior to secant wall construction.

Misaligned piles can affect projects in multiple ways. If the interlock between primary and secondary piles is broken, unwanted soil and water can ingress into the excavation, which will require immediate remedial works (typically through resin injection).

Having sufficient interlock is not only important where it can be seen, i.e. above excavation level, but also below this level to guarantee sufficient water cut-off to make the excavation safe and free of running water. Groundwater entering the excavation from the bottom can destabilise the soil and, in extreme cases, cause uplift failures which should be considered in the geotechnical design of the basement (BS EN 1997-3:2025 – Eurocode 7 – Geotechnical design. Geotechnical structures). To avoid these, the design of the basement should be accompanied by a groundwater management strategy (CIRIA C750 ‘Groundwater control: design and practice’).

In severe cases, a misaligned pile (shown in Figure 5) can impact the spatial requirements of the basement, e.g. the position of liner walls. In these cases, either the out-of-position pile or the secondary element will require structural modification, potentially impacting layouts, available space or structural capacity of the secant wall itself.

Water Ingress

For the avoidance of doubt, secant walls are rarely found to be perfectly watertight. Due to the number of joints between primary and secondary piles, secant walls are vulnerable to water ingress. Damp patches and beads of water (individual droplets of water) are to be expected and do not constitute a defect. The size of damp patches, however, should be less than 4m² per patch, or less than 10% of the visible face of the wall (refer to ICE SPERW 3^rd Edition, Clause B1.9.1 for further details). Weeping water, i.e. where the water runs down the face of the wall, is not acceptable.

Water ingress may occur even if there is no visible sign of misaligned piles. An allowance should be made in the construction programme to permit the piling contractor to deal with leaks through resin injection or other sealing methods.

It is also important to understand that secant walls are classified as Type B protection against water ingress (see BS8102:2022, Table 1) and alone cannot provide a performance level better than Grade 1b (no seepage, damp areas from internal and external sources are tolerable) in accordance with BS8102:2022, Table 2.

Protrusions

Protrusions refer to irregularities on the exposed face of a secant wall after excavation, see Figure 8. Instead of a vertical surface, the wall may have protrusions extending beyond the face of the wall into the excavation. Whilst this is not a structural defect, it can have consequences for follow-on trades and potentially the construction programme.

Protrusions frequently occur in

> Loose natural granular soils or soft clay deposits

> Poorly compacted or poorly graded backfill after obstruction removal (often associated with the removal of an old basement).

> Certain ground conditions where over flighting is a risk associated with CFA techniques (refer to FPS Guidance paper ‘CFA Piling: Preventing ground & rig instability through over-flighting’).

Protrusions in soft/loose/insufficiently compacted ground cannot easily be controlled by the piling contractor. The piling contractor is only responsible for the removal of protrusions in excess of 100mm thickness (ICE SPERW 3^rd Edition, Clause B11.4.2). It is therefore important to allow sufficient time in the construction programme to deal with protrusions, although it is structurally permissible to leave protrusions in place unless they interfere with waterproofing or finishing works.

Concrete Defects

Concrete quality is critical for durability and long-term performance of secant pile walls. Defects can occur during placement and often remain unnoticed until later stages. Using a trialled and tested concrete mix design from established concrete suppliers and undertaking concrete performance testing, are effective ways to minimise the risks of defects. How the concrete is handled on site, for example, avoiding changes to concrete properties through the addition of water, and ensuring the timely and appropriate placing of concrete in accordance with the relevant standards, such as BS EN 1536, ICE SPERW, EFFC Tremie Guide is also of vital importance. Inadequate base cleaning or support fluid exchange, poor tremie practice (RBP only) or concrete supply interruptions can also affect the final product.

Some common concrete defects in secant walls include:

> Shadowing/mattressing, refers to situations where concrete does not flow adequately around the reinforcement bars and leaves ‘shadows’. This defect only occurs in rotary piles.

> Inclusions in piles, which are a common problem and are often the result of inadequate concrete workability. They consist of entrapped materials that differ from the specified concrete and can originate from the surrounding ground (soil or groundwater), poorly cemented material from the original segregated concrete, and may also contain drilling fluids (if used during construction). Inclusions occur more frequently in rotary bored piles as the concrete is placed after the installation of the reinforcement cage and must flow around the bars, but can also occur in CFA or CCFA piles when the concrete has lost its workability.

As a result of inclusions, concrete cover becomes inadequate requiring remedial work. If the inclusions are extensive, they may also provide additional pathways for water ingress (though the reduction of interlock) and may require the down-rating of pile/wall capacity.

What to Expect

Many disagreements occur when expectations between parties are not aligned. The points below summarise what can reasonably be expected:

Secant pile walls are not fully watertight

Secant pile walls manage groundwater inflow, but they do not provide completely dry basements. Damp patches or minor seepage are common and should be anticipated. Flowing water or concentrated leaks, however, are unacceptable and usually indicate defects requiring remedial works. Waterproofing should always follow BS 8102:2022 guidance, with allowances for remedial sealing such as resin injection.

Damp spots do not mean defects

Clients often expect a completely dry basement. In reality, even with a well-built secant wall, some moisture may appear. This is normal and should be addressed through the waterproofing strategy, not treated as a defect.

Overbreak is common

Expect some irregularity on the exposed wall face after excavation. Overbreak often occurs in loose granular deposits, soft clays, or poorly compacted backfill from obstruction removal. Whilst it does not present a structural problem, it complicates waterproofing and finishing works. Extra trimming or patching may be needed, which can affect programme and cost.

Straightness varies by technique

Walls formed using rotary bored piling (RBP) tend to achieve better verticality, greater interlock and straighter faces than those installed with CFA methods. However, while these advanced systems deliver superior alignment, they come at a higher cost.

Consequences for Projects & Claims

When secant pile walls do not perform as expected, the impact is rarely minor. Even small defects can significantly affect the programme and budget. The following outcomes are typical:

Remedial Waterproofing

If water ingress occurs, the leaks are usually treated by polyurethane or acrylate gel injection. This treatment generally stops the leak but can be very disruptive. Injection requires specialist contractors, access to the affected areas, and often multiple visits. Blocking one leak often causes others to appear, meaning costs can increase quickly, and programmes become delayed.

Additional Surface Preparation

Whilst overbreak may be more of a cosmetic problem, it can mean that the wall face is not ready for waterproofing straight away. Trimming, patching, or applying thicker coatings adds time and labour. These tasks are rarely in the original programme, so delays are common.

Structural Downgrades

In rare cases, if tolerances or concrete quality fall short, the wall’s structural capacity may need to be reassessed. This can lead to redesigns, additional props, or strengthening measures, all of which add cost and complexity.

Programme Delays and Cost Overruns

Every remedial step, whether sealing leaks or smoothing surfaces, pushes the schedule out. Waterproofing trades cannot start until the wall is prepared, and follow-on activities like slab casting or fit-out are held up. Claims for delay and disruption are common in these scenarios.

Bottom line: Defects, even cosmetic ones, can have significant commercial consequences. Early planning, engagement with relevant specialists, realistic tolerances, robust quality control, and allowances in programmes are the best approach to avoid subsequent issues.

From our experience, it is essential to follow these steps to minimise issues on site or disputes:

> Define the waterproofing performance grade early (BS 8102:2022) and appoint the waterproofing specialist at the concept stage.

> Select the right wall type for depth, deflection limits and groundwater context (CIRIA C760).

> Make allowances for realistic tolerances (ICE SPERW).

>Plan groundwater management: combine secant cut‑off with dewatering where required; design for uplift; protect adjacent assets (CIRIA C750).

Conclusion: Why Early Attention Matters

Secant walls make complex basements possible, but they are not an “install and forget” solution. Misalignment, protrusions, water ingress, and concrete defects are all common issues that can lead to extra work, cost, and programme delays. Most “problem basements” are not the result of a single catastrophic error – they often stem from a series of small, foreseeable mismatches between design assumptions, construction tolerances, and waterproofing expectations. Addressing those early is far cheaper than dealing with issues later. Standards and guidance exist; the key is to use them proactively.

If you are facing secant wall performance questions, planning a deep basement, or navigating a claim, Hawkins can help – from early risk reviews and design due‑diligence to independent failure analysis and expert evidence. We translate complex geotechnical issues into clear advice and defensible conclusions for clients, contractors and insurers.

About the Author

Yvonne Ainsworth is a Chartered Civil Engineer and Principal Associate at Hawkins, with over 25 years’ experience in geotechnical and structural engineering. Her career includes senior roles delivering complex foundation and retaining wall projects, including secant and diaphragm wall construction on major UK infrastructure schemes. Yvonne is widely recognised for her expertise in piling, ground engineering and resolving high-risk technical challenges, with experience directly relevant to the behaviours, risks and performance of secant pile walls discussed in this article. She brings specialist insight into design, construction methodologies, and failure investigation in complex ground conditions.

References

BS 8102:2022 – Protection of below ground structures against water ingress — Code of practice

BS EN 1536:2010 (+A1:2015)- Execution of special geotechnical works – bored piles

BS EN 1997-3:2025 – Eurocode 7 – Geotechnical design. Geotechnical structures

CIRIA C750 – Groundwater control: design and practice, second edition, 2016

CIRIA C760 – Guidance on embedded retaining wall design, 2017

EFFC Guide to Tremie Concrete for Deep Foundations, 3^rd Edition,2024

FPS Guidance Paper ‘CFA Piling: Preventing ground & rig instability through over-flighting’, 2014

ICE Specification for Piling and Embedded Retaining Walls, 3^rd Edition, 2016

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Hawkins Hosts Inaugural ‘Burning Questions’ CPD Reception in Dublin

Chloe Duggan — Thu, 04 Jun 2026 10:28:14 +0000

Hawkins recently hosted our first Burning Questions event in Dublin, welcoming clients, colleagues, and industry professionals to The Merrion Hotel for an engaging session focused on forensic fire investigation.

The afternoon began with an informal welcome over tea and coffee, before guests attended a CPD presentation accredited by The Insurance Institute of Ireland. Delivered by Hawkins experts and guest speakers, the session provided both technical expertise and practical insight.

John Holland, Regional Director for the Island of Ireland, opened the event with an update on Hawkins’ continued growth and development. He highlighted our recent international expansion into Italy, Abu Dhabi, South Africa, and Australia, as well as the acquisition of A. Lamb Associates (ALA) and its subsidiary, Morham + Brotchie Partnership (M+B). This development strengthens Hawkins’ ability to provide integrated technical, quantum, and delay expertise on a single case, enhancing the service provided to clients.

The presentation centred on a detailed, multi-disciplinary case study, taking attendees through each stage of a complex fire investigation from identifying the origin through to recovery considerations. The scenario explored a fire caused by a defective e-scooter, which spread rapidly through a terrace of converted residential properties, raising important questions around causation, fire spread, liability, and compliance with construction standards.

Ian Stafford, Major and Complex Loss Adjuster at Davies Group, outlined the practical challenges of handling significant losses and emphasised the value of early investigative input. Hawkins fire investigator Jason Buchwitz explained how the origin of the fire was identified and alternative causes eliminated, while structural engineer Killian Walsh explored how shortcomings in fire-stopping contributed to the spread of the fire.

Legal considerations were addressed by Martin Browne of HF (formerly Horwich Farrelly), who discussed potential recovery routes and liability issues. The session concluded with insights from Hawkins’ forensic architect Paul McCaughran, who highlighted design and construction shortcomings that failed to meet building regulation requirements.

The event demonstrated how a coordinated, multidisciplinary approach can effectively resolve complex claims, offering attendees a clear understanding of how expertise across disciplines contributes to determining cause, responsibility, and outcome.

Following the presentation, guests attended a drinks reception with canapés, providing an opportunity to continue discussions in a more informal setting. Attendees also had the chance to explore casework exhibits, including virtual reality photogrammetric models, offering a closer look at the investigative techniques discussed during the session.

Thank you to everyone who joined us, we look forward to welcoming you to future Hawkins Events.

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