Peebles High School

This Scottish Borders Council project, delivered by Hub South East Scotland and with BAM Construction appointed as the main contractor, was designed by Glasgow-based architect Stallan-Brand. The intriguing plan of the project, designed for 1400 pupils, was essentially dictated by the former rugby pitch whose footprint it occupies, while the scale has in part been limited to two storeys in order to respect the ‘county estate’ style of nearby properties. Internally, however, the layout’s concept is described as creating an ‘orchard of learning’ where a rigorous grid and pathways, both north–south and east–west, are broken up by ‘clearings’ in the form of atria. Intended to nurture a collegiate feel for the young people who will attend Peebles’ new seat of learning, these atria are to be associated with the different departments and their functions. But they have also had an impact on the method statement for the build, as they break down the otherwise rectilinear floorplates into smaller, more complex areas.

The Scottish Borders are famous not only for their landscape but also for the frequently wet weather that rugby matches and other school sports are played in. The ground conditions for this project have definitely presented their own challenges, with soil investigations revealing some made up ground and a high silt content before sandstone bedrock is reached approximately 10m down. While groundwater and a gradual slope to the land were also issues, Careys had to carry out cement stabilisation of the silty sub-soil prior to beginning excavation work for casting of pad foundations and installing the mains drainage.

The casting of the main ground[1]bearing floor slab in a series of pours is currently well advanced, while the construction of the ground-floor columns using conventional formwork is also being undertaken by Careys’ teams, along with subcontractor steel-fixers. Following an early appraisal by regional operations manager James Purves, a centrally located tower crane was erected to provide the main lifting capacity, in preference to the pair of mobile cranes originally envisaged.

The programme will then see Careys’ specialist formwork installation gangs rapidly manoeuvring multiple sets of the Topmax table system into position using the manufacturer Hünnebeck’s trolleys; though on many of the multi-storey structures the company has constructed with Topmax, the special crane lifting forks have been deployed.

Kurt Sartorius is the senior technical engineer at Careys, responsible for evaluating all the company’s hiring and purchases of slipform, jumpform and other systems used on a project by-project basis, and was also responsible for assessing the Topmax table form when it was introduced by Hünnebeck, formerly SGB.

He recounts, “Back in 2015, we were looking for ways to improve efficiency and site productivity – along with safety and better control of site traffic – so were in discussions with a number of key suppliers, while Hünnebeck had just introduced the Topmax table form system. Careys was not only the first company in the UK to trial the system but we also tested it and I produced a full briefing document for our internal use.”

That assessment led to the company buying a significant quantity of the versatile unitised formwork solution, which has continued to be used for a sequence of educational, commercial and residential contracts, including some that are much more complex than the two-storey school in the historic Royal Burgh. While the company’s first trial of Topmax was on a residential project at Beith Street in Glasgow, other education projects delivered by the firm in Scotland over the past few years include Anderson High School, Aberdeen University, The University of Glasgow, Oban High School and James Hamilton Academy. Sartorius continues, “Careys carries out a value-engineering exercise on every project it undertakes, with formwork proposals evaluated back to overall method, detail and cost in the first round at tender stage, against cost to the company. In the case of a contract such as Peebles High School, we held sufficient kit to meet our requirements, but we are also hiring additional forms and other fittings as necessary.

“In addition, for each project, we pass our preliminary design brief to Hünnebeck and it does the design layout for us, with the knowledge of how we have developed our usage of the Topmax system. This enables us to determine what items we need to rent on top of our stock items. It does an initial design and then engineers and supervisors will mark up the drawings with the pour lines so it can be tailored to optimise production.

“We routinely try and pick our guys who have experience with the systems we are using for any project, so that they are familiar with the individual items. Understanding the strengths, and limitations, of different systems is almost a language you have to learn. Topmax is a system we have adapted over time and one of a number of formwork solutions we’ve become very comfortable with using. In addition, we are very good at imparting knowledge to our personnel, while our Black Hats (supervisors) are trained to bring the best from the various teams they look after.”

The key components to the Topmax system are the Ecoply-faced tables themselves, which measure 2.4m or 1.8m × 5.4m, with the special crane hook being able to lift a double unit – having a total area of 26m2 – out from beneath one level, once the target strength has been reached, and place it ready for the next. The tables require only four of the folding legs to be in place for slabs of up to 500mm thickness, while there are both ‘castle-head’ connecting bearings and diagonal struts to ensure stability. At corners or for infill sections, Topmax provides timber holders for the carpenters to build off with square[1]section wood. Across the system, components such as the centring tension bolts are both ergonomic to use and straightforward to maintain, all enhancing the speed and practicality for the teams involved.

On the Peebles High School project, each of the 250mm-thick floor slabs will be cast in a total of eight pours, working from left to right across the footprint of the building, with an expected turnaround of eight days between pours.

The new school and its remodelled environs are due to be fully completed and ready for final handover by summer 2026.