How Our Team Build Around Uneven Terrain

In the construction industry, no two sites are the same, particularly when adding new buildings to an existing facility. In the 21 years our team has worked across the UK, we’ve been faced with some steep challenges when it comes to site surfaces, from complex underground utilities to unsuitably loose ground. 

Thanks to our in-house design team and customisable modular system, we’ve been able to deliver in these cases and more, building our clients the new space their students need without compromise.

Here, we’re going to explore several projects where our team had to go above and beyond to deliver around a challenging ground environment, creating fantastic buildings through our flexible panelised system.

Navigating underground utilities and tree roots at Stepgates

Our team opted for a screw pile foundation at the Stepgates site

TG Escapes was approached by Stepgates Community School in Chertsey who needed a new SEND block, both to increase pupil count and to improve the quality of their provision, incorporating modern classrooms and breakout spaces tailored to SEND pupils. The project presented a unique set of challenges that required careful planning and innovative solutions.

While the site for the new building had a solid bearing capacity of around 200 kPa, it housed existing underground utilities, including a soakaway that would need to be moved, and was also located within a tree root protection zone. These two factors meant that we couldn’t use traditional foundations that would disrupt these protected elements.

Our team, working under technical director Chris Leese and Structural Engineer Oscar Lueng, opted to use screw pile foundations to navigate the elements that couldn’t be disturbed. Screw pile foundations involve large metal anchors being screwed into the ground, offering an excellent level of support without the disruption of concrete foundations. An added benefit of screw piles is their lower carbon footprint, alongside a fast installation process.

Using a screw pile foundation, we were able to navigate around the underground services and tree roots without disruption, while also maintaining a minimal impact on the surrounding environment. This ensures that Stepgates can have the bespoke SEND spaces their students need.

Dealing with poor soil conditions and water table issues at Solihull Sixth Form College

We used warm raft foundations at Solihull school

In summer 2024, we broke ground on a new extension at Solihull Sixth Form College, adding 8 new classrooms to accommodate a growing pupil headcount. The project presented our team with particularly difficult ground conditions. The site was located near a high floodplain, and the presence of a high water table (when groundwater is near the surface, saturating upper soil layers) further complicated matters. These factors resulted in poor soil conditions, with the clay soil having a low bearing capacity of just 30 kPa with the potential for significant settlement of up to 40mm. Settlement in clay soil can lead to parts of the building sinking over time, something it was crucial to avoid. Lead architect Mark Guyatt, supported by Harry Wilkins and Gabriel Cristea, worked to tackle these problems at the design stage, ensuring the long-term stability of the new building.

Our team pouring foundations at Solihull

We devised a solution that avoided the need for piling, which would have made the project unviable financially, instead opting for a warm raft foundation. This consists of a reinforced concrete slab with a layer of insulation beneath the concrete, ensuring that the floor structure is ready for final floor finishes. Warm raft foundations can be used to overcome poor ground conditions or to meet a requirement to provide a solid concrete floor. Once formed, there is no requirement for further insulation and floor screed, meaning they will save a project both time and money.

This method allows us to accommodate anticipated soil settlement, while avoiding more costly piling, ensuring the project could continue on budget and schedule despite its challenging site conditions.

Building on made ground at Allen Edwards

The complex foundations at Allen Edwards school

When Allen Edwards Primary School approached us to construct a new SEND building, it was immediately clear to project managers Tom Hillier and Clive Hicks that the site posed a unique challenge. The only available area had been filled with made ground (loose materials like sand and clay) from a previous construction project around 15 years earlier. This created poor ground conditions down to a depth of 3 meters. There was no choice but to remove it.

Our team worked to remove the made ground before compacting and proof-rolling (a method of testing subgrade performance) the upper soil layers below. 

Due to the excavation, we were left with a large hole in the ground. Rather than import lots of expensive material to fill the hole, our engineers designed a cold raft foundation at the base of the hole and built up levels using masonry block work and a thick layer of EPS insulation, which was a far more economical solution. This provided a well-insulated concrete floor ready for finishing and ensured the building was at the correct height to suit the rest of the site.

Thanks to this solution, we were able to build the new SEND space with minimal disruption to the school, meeting their project budget despite complex site issues.

How our team approaches difficult projects

We utilise a panelised modular approach that is especially suited for projects with challenging ground conditions, combined with a fully bespoke design process. When approached by schools or contractors, we start with a thorough survey of their site, identifying any challenges that require a tailored approach. 

Our in-house team of architects can incorporate a variety of foundation types, while our panelised system means that we aren’t limited in terms of layout like volumetric approaches. In general, a timber-based modular approach will also be lighter than traditional brick-and-mortar ones, making them more suited for sites with ground issues.

We start every project with a complementary design process, where our architects and designers put together a detailed blueprint for a finished building, which comes with a comprehensive upfront price for every aspect of the work. This helps us to put clients at ease regarding the suitability of their sites and the potential high costs associated with building on their challenging soil conditions.

Offsite construction also allows us to fabricate the building components in a controlled environment, accelerating the build time. This approach reduces disruption to both the site and the surrounding environment, making it ideal for projects in sensitive or complex locations.

Prioritising sustainability at every stage

Since opening 21 years ago, sustainability has been something we’ve prioritised at every stage of the construction process. Our use of eco-friendly foundation methods, such as screw piles foundations, allows us to significantly reduce the environmental impact, even on challenging sites. These thinner, low-impact foundations require less excavation, preserving the natural landscape while reducing the carbon footprint of the project. We also use sustainable timber frames on every building, designed by Nicola Robson and Hossein Mahdavinezhad, offering excellent strength across a lifespan of at least 50 years.

By combining offsite fabrication with swift on-site installation, we further minimise disruption to surrounding habitats, ensuring that sensitive ecosystems are protected. Every project we work on is designed to meet net-zero in operation as standard, thanks in part to our team embracing these new foundation types.

Facing a difficult building project?

Whether you're dealing with a complicated site or a more straightforward one, TG Escapes has the expertise to provide a fantastic solution. Our panelised modular system and bespoke design approach ensure that we can tackle even the most challenging ground conditions, from uneven terrain to sensitive environmental areas. With a strong focus on sustainability, we minimise the environmental impact at every stage of the process while delivering high-quality, durable buildings that meet your exact needs. Contact us today to begin your free design process and see how we can bring your vision to life.