Archives: People

Sarah McDonnell

Sarah is Director of Project Management for the TFT Dublin office. She brings over 25 years of industry experience to TFT and has worked on a wide range of work overseeing all project management processes from purchase, through to design development and construction contract completion.

Her extensive experience includes projects across all industry sectors. Prior to joining TFT, Sarah worked on both client side for a prominent Irish property developer and also leading the refurbishment and Fit-Out division of one of Ireland’s leading contractors. Past clients include IPUT, Willis, JP Morgan, Google, KPMG and Hines.

Outside of the office, Sarah sits on the Board of ALONE, a charity dedicated to enabling older people to live independently at home and is also on the judging panel for the Irish Construction Excellence Awards.

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Outside of work I am a mum to Aimee and Daragh, wife to Dave and chief dog walker to Pebbles. Weekends are usually spent as a taxi driver to matches, helping out on the local school’s Parents Association or trying to get my handicap down on the local golf course.

RAAC in commercial buildings: what do you need to know?

Reinforced aerated autoclaved concrete (RAAC) is in the headlines following high-profile building failures and public scrutiny on the risks remaining to public buildings around the country. But is RAAC a material of concern for commercial buildings? If owners or occupiers of commercial buildings suspect that their buildings are constructed using RAAC, what should they do?

Many commercial building owners are aware of risks relating to RAAC and have developed guidance notes on its identification and management. But now, in light of widespread coverage of RAAC and its risks, many more people want to understand their exposure to it.

TFT Partner Jay Ridings has written on this issue for the RICS’ Built Environment Journal, and we’ve also compiled this set of frequently asked questions about RAAC. If you want to know about its origins, its use and management today, read on.

Do you want to speak with our team urgently about RAAC and what it might mean for your commercial property? Get in touch with Jay Ridings direct, by clicking here.

What is Reinforced Aerated Autoclaved Concrete (RAAC)?

In brief:

Aerated autoclaved concrete (AAC) is much lighter and softer than regular concrete, with lower thermal conductivity. AAC was originally developed in Sweden to form lightweight thermal blocks and, using the same method, wide reinforced planks (Reinforced Autoclaved Aerated Concrete (RAAC) planks) were created. These planks are commonly found as roof decks, flooring and internal partitions. Occasionally they are also used as external walls.

What are the weaknesses of RAAC?

The greatest concern with RAAC planks is their potential for sudden shear failure. If a building structure is going to fail, we want this to happen by degrees so that there are warning signs to act on instead of immediate catastrophic failure. The reason for the shear failure is due to issues with the steel reinforcement, typically at the end of the planks.

Other concerns leading to deterioration of planks potentially impact their structural stability. Planks are prone to deflection and sagging, particularly if:

  • Planks are incorrectly detailed
  • Working loads have been underestimated
  • Elements are undersized
  • Reinforcement is inadequate

If there is sagging there is the potential for cracking and for the steel reinforcement to become exposed to moisture which could lead to corrosion. If roof planks begin to sag, water can gather on the roof above them (known as ponding). This may increase the load on the sagging planks, leading to further moisture ingress, exposure of the steel reinforcement, corrosion, and cracking.

Is RAAC found in commercial buildings?

In our experience, it is rare to see RAAC planks within commercial buildings. RAAC is most prominent in the public sector, notably schools and hospitals, but there are reports of its use in court buildings, prisons, and police stations.

However, these planks were available commercially and may be in buildings other than the above. In addition, buildings do change in their use and ownership over time, so there will be instances where buildings constructed within the public sector are now privately owned.

How do I know if my building contains RAAC?

There is no central register of buildings with RAAC planks, so identification depends on local knowledge and independent inspections. Here are some simple principles for identifying RAAC planks:

  • Panels 600mm wide
  • A distinctive V-shaped groove at regular spacing
  • White or light grey colour
  • On records or drawings, planks may be referred to by proprietary names such as Siporex, Durox, Celcon, Hebel and Ytong
  • Panels are very soft and if you press a screwdriver or nail into the surface, you will be able to make an indentation. Please note: care should be taken when investigating in this way as applied surface finishes may contain asbestos.
  • Inside, planks will appear bubbly like an Aero chocolate bar, with no visible stones (aggregate) in the panels.

If you suspect RAAC in your building, then an appropriately experienced Chartered Structural Engineer or Chartered Building Surveyor should be appointed for identification and inspection work.

Their investigations will include but are not limited to:

  • Assessing cracking
  • Measuring deflections
  • Reviewing water penetration and corrosion
  • Using cover meters to assess regular spacing of reinforcement
  • Checking that reinforcement extends to the end of planks and is properly supported
  • Taking and sending samples for laboratory testing

How can I manage RAAC?

If RAAC is discovered, you must undertake a risk assessment considering the use of the building, the areas affected and any deterioration of the structure. The position of reinforcement can be scanned using a cover meter and samples can be tested for carbonation, which is a sign that cracking could follow.

Structural engineers often recommend RAAC planks to be removed or strengthened wherever they are found, regardless of condition. This is because of the risk of sudden catastrophic failure and the fact that these planks are likely to have exceeded their design life. Subject to a full assessment of the risks, it may be possible to take a different approach.

Can you help me investigate RAAC in commercial buildings?

Yes, our team of Chartered Surveyors is on hand to investigate and manage improvements works for commercial buildings.

It is very likely there will be further discoveries and media attention on RAAC. News of failing buildings due to this outdated material highlights the urgent need for guidance and action to identify and implement remedial solutions.

Get in touch here to speak with our team about RAAC and what it might mean for your commercial property. Get in touch with Jay Ridings direct, by clicking here.

BPP Lion House, Cambridge

The property is a mixed-use primarily retail complex incorporating the city library of Cambridge. The third floor of the building is occupied by an education provider with reception area, classrooms and dedicated washrooms.

As part of continued investment in the premises, by the asset manager and to support the ongoing service of the education provider to the city of Cambridge, TFT managed a design and build landlords CAT A and occupies CAT B fit out of the third floor.

The project included a new heating system an improved passive and dynamic fire protection and also presented an opportunity to move away from the existing gas supply to a fully electric HVAC system. The system supported the occupiers net zero commitments, and the project reached an EPC of ‘B’ with 38 points.

Jay Ridings

Jay Ridings is a Senior Director and a chartered building surveyor (MRICS) and leads the technical due diligence service line, as well as contributing to the TFT leadership groups for fund monitoring and fire safety.

Jay has a keen interest in developing and improving TFT’s reporting, adopting the latest technology to communicate survey findings, streamlining the TDD process to assist transactions and providing holistic, commercial advice, integrating all of TFT’s specialisms.

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Out of work, I have a sociable time with three children, dog walks and lunches, reading (once everyone is eventually in bed!) and very active holidays camping and skiing. Occasionally I make it to a yoga class or get onto the golf course.

TFT charity spotlight: 1625 Independent People

Support for our local communities and charitable causes is central to TFT life, and has been throughout our 50 years! Each of our offices has strong local charity partnerships, so we can use our Volunteer Days, our skills and our resources to help many causes close to our hearts.

One of the longest relationships we have is with the Bristol-based charity 1625 Independent People (1625ip). They help vulnerable young people in Bristol and South Gloucestershire with housing, personal support, training and employment to overcome a hard start to life and gain a better footing for their future.

Through some 15 years, the TFT team has worked with 1625ip to raise money, share equipment and resources to set young people up for success. Today, the charity’s services help more than 1000 users at any one time!

Kingsley Hall

A major challenge for 1625ip is to refurbish Kingsley Hall, its Grade 2* Listed site in Bristol’s Old Market conservation area. It needs to turn this heritage building into a sustainable, long term and beneficial place for young homeless people to turn to, to overcome isolation, develop their skills and rebuild their lives.

The project will create:

  • Great spaces for young people to meet and receive training
  • A skills kitchen
  • A social enterprise
  • Housing for young people who have been homeless
  • High-quality office space for 1625ip colleagues

To keep the project moving forwards, 1625ip is always looking for support from anyone who can offer it. If that could be you, get in touch with us, or with the charity directly, here:

More support for the future

Not only has the charity grown, but it offers new support as the world changes. 1625 Independent People is 40 this year, and in the beginning its focus was on those who struggled with alcohol and drug use. Today the charity has a wider remit covering mental health, diet and neurodiversity challenges across society, which present major barriers for young people to progress.

So the support we can give through our time and our resources can benefit more people in the Bristol and South Gloucester area today than ever before.

As both 1625 Independent People and TFT look forward to celebrating major milestone birthdays this year, we can’t wait to keep working together for many years to come.

How can you help?

If you’d like to find out more about 1625 Independent People, what better way than to check out their upcoming sleepout challenge? Click here to sign up, and click here to see which sponsorship opportunities remain.

If spending a night under the stars isn’t your thing, fear not. You don’t need to bring a sleeping bag to enjoy the festival they’re putting on in the heart of Bristol. There will be live music, tasty food and a chance to meet the young people who benefit from 1625IP’s amazing services.

Come and join us at the Bristol harbourside on 2nd November 2023, to see for yourself how much good this charity is doing for young people in the region.

Osama Shawky

Osama is MSc/MBA mechanical engineer with over 18 years’ proven record of technical engineering, academic research and business development experience.

Over the last 8 years, Osama’s focus has shifted from M&E design to Sustainability, leading building performance simulation and energy related workstreams, using a range of modelling approaches, tools, and techniques to bring about fundamental change and improvement in Energy performance, and to help thru the journey towards Net Zero.


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Away from work, Osama has a keen interest in camping & fishing, he’s dedicated to exploring the unknown, and embracing the wilderness of the great outdoors.


My BE Career: Emily Baigent, Sustainability Graduate

Across the many roles, levels of experience and subject experts in our team, what comes through loud and clear is the shared commitment to a better future for our industry, and our drive to help it get there. What does that look like? Emily Baigent shared some thoughts with industry magazine BE News recently, which gives a great perspective on that issue and many more.

Emily joined us on a student placement programme earlier this year, before becoming a full-time member of the team this month. To mark the occasion, she shared her views of the industry with BE News, including: the links between diversity, equity & inclusion, climate change, and the need to broaden our industry’s appeal for talented, passionate people.

It’s a powerful message as we seek to reach more individuals who have skills and perspectives to help create an even better built environment into the future!

“If more people had the opportunity to fall in love with the built environment, the world would be a far healthier and happier place to live.”

We couldn’t say it better ourselves! Read the full interview with Emily on BE News, here.

Cladding Safety Scheme: funds for building remediation works

The new Cladding Safety Scheme is open, and TFT is here to help building owners and occupiers access it. Although the application process can be complex, we offer four steps of support to help you secure the right funds and deliver safer buildings.

What is the Cladding Safety Scheme for?

The Cladding Safety Scheme is the second fund established by the UK Government to remedy unsafe cladding in residential buildings. This scheme is for buildings over 11 metres high. However, in London the scheme is only for medium-rise (11-18 metre) buildings.

The funds are only for remedying unsafe cladding on external walls. A condition of the funding is for you to carry out these remedial works swiftly, and to keep leaseholders informed along the way. 

Who can access these funds?

The person responsible for the external repair of the building is responsible for applications. This might include the freeholder, a Local Authority, a Right to Manage company or a Property Managing Agent.

In most cases, developers or owners which have signed up to the Developer’s Pledge should pay for building remediations through the Developer’s Pledge policy.

Whichever party is accessing the funds, they will need specialist support helps to compile the right information for success.

How can I apply for Cladding Safety Scheme funds?

The application process can be complex, requiring accurate building information and details of the proposed works to proceed, including: 

  • A compliant fire risk assessment of the external walls (FRAEW) by a competent professional which identifies the cladding systems which require remediation
  • A work package with full contractor schedule and costs 
  • Statutory consents for the works
  • Demonstrated value for money in the works package (by getting multiple quotes or running a tender process)

Missing information can lead to rejected applications, meaning more time taken to access the funds and remedy unsafe buildings. 

Four steps to secure the funds and complete the works

TFT has an experienced team ready to manage the assessment of buildings and support you through the process from end to end. We know the information required to support your application for building safety work funds. 

Our four-step process gives your application the best chance of success, and includes project managing building safety works to improve your buildings swiftly and with transparency. At the end of the process, building owners will have clear documentation to record the quality and detail of the works.

The result is peace of mind for building owners and occupiers.

Find out how this process can help you understand your building risks, and secure the funds to put them right. Get in touch with Robin Holme, here.

Building information modelling (BIM) for precision design

Building Information Modelling (BIM) is widely known across the construction and real estate industry. But how well are its benefits understood on a practical level, for different project types and sizes?

A project of ours at Wellesley Court shows how BIM can be integrated in projects of any size, not just major high value developments. The technology can support efficient and effective works when they are needed most.

This residential property comprising numerous flats in Maida Vale, London, requires replacement hot water storage units to serve all dwellings within the building. However, with an operational plantroom the challenge is to minimise disruptions to residents’ supply, so careful design was essential. Some challenges included access to the space and consideration to the presence of asbestos within the plantroom.

Precise data capture

In order to aid the design process, TFT’s Geomatics specialists captured a colourised 3D point cloud of the existing architecture and M&E services. Utilising the Leica RTC360 we were able to access the hard-to-reach areas, positioning the LiDAR scanner in a number of positions throughout the plantroom to ensure high resolution capture whilst ensuring no disturbance to the existing services.

From this, we produced a spatially accurate digital twin of the plantroom to millimetre accuracy – meaning the designs we created from it would fit in the real world. Revit was used to convert this geometry into a 3D model visualising the mechanical and electric plant systems, including details for each element within the model.


However, this 3D Revit model is not yet a building information model (BIM). We then added an additional layer of data: everything from wall materials to a pipe’s thermal qualities.

Combining many data points with the virtual model creates a BIM model: a highly relevant and easily understandable set of data which is accessible and useful for all.

Reliable, accessible, valuable

This scan-to-BIM workflow allowed TFT’s M&E team to create precise designs, with reliable ‘clash detection’ showing how well elements would fit in the space before the project began in the real world.

Furthermore, this model data is shared on with other TFT specialists. For instance, our principle designers can use the same model to ensure that the existing services risks and hazards are clearly identified to the contractor. The data will also be used to add to the asset schedules, providing full information for future maintenance works, and even informing technical due diligence surveys in the event of a sale, speeding up that process and helping to deliver the best value for the building.

Find out what our BIM and data specialists can do for your buildings. Get in touch with James Ingall here.

Now open: Adventure Play at Windsor Great Park

Our project management team brought their playful spirits to their work and delivered Windsor’s brand new Adventure Play Park, for The Crown Estate. This is a place of giant acorns, treehouses, suspended walkways and more, giving children a natural, multi-sensory play experience.

The Adventure Park covers 1.2 acres and is created using sustainably-sourced wood from the Windsor Estate, providing an extensive playground for families to explore together. Its obstacles and activities are tiered for children of different abilities and confidence, including a fully accessible route.

We managed this unique project for The Crown Estate to create a natural, hand-crafted and accessible world for little ones (and bigger ones) to lose themselves in play. See how it looks here:

Find out more about Adventure Play at Windsor Great Park, here: