The great Scape from CLASP Tom Ridley-Thompson, design director at Scape, on continuity and change in its steel-framed system
Scape is nothing new. Its former guise, CLASP (Consortium of Local Authorities Special Programme), was set up in the late 1950s to meet a demand for school building. It was always a steel frame
but went through various developments, going from Marks 2-6, although its heyday was in the 1960s-70s with Marks 3-4, where it developed a definitive and recognisable aesthetic. After 1979, when public sector building fell off a cliff, a lot fewer were built, but over that time it also became a less stylistically rigorous system, more flexible and open-ended. Pitched roofs came in and the use of traditional cladding.
By the 1990s, a CLASP building was not recognisable as visually different from any other typical public sector building of the time. In a sense, Scape has carried that open-endedness and flexibility on, but has learned from the past and significantly simplified the steelwork design. CLASP buildings suffered from the intrinsic design problem of being riddled with internal cross-bracing bays, so that layouts were pretty much fixed and not easily remodelled. Now any bracing is limited to the external frame. Also, production of the CLASP
steel frame was reliant on a limited number of centralised fabricators,
involving materials having to travel. Our system of standard universal beam and universal column steel sections can be manufactured by local fabricators — good news for local employment, as well as reducing carbon miles. Our aim is to make structure work as hard as possible, which also minimises use of resources. Foundation design has also
evolved. CLASP always used pre- cast raft foundations that could be as little as 100mm in depth, but they were historically more expensive to procure. We’re still using raft foundations, but in-situ cast ones, which are also a lot thicker to meet current codes and
which again makes use of local skills. There’s no deep excavations, and they can be used on all but the poorest ground, where we’ll use piled foundations. Any building procured through
our framework agreement, such as Great Denham, uses an NEC contract, although outside the framework we can use traditional tendering — it’s all about client choice. Architects are also not locked into a pre-defined aesthetic. It’s best if we work with them from the outset, and while there’s a bit of a learning curve initially, we’ve successfully collaborated with the likes of Aedas and Bond Bryan to produce some really good buildings.
Above: The CLASP frame system went from a defined aesthetic in the 1950s and 60s to one that could incorporate any type of architectural style
four labourers and a crane driver,” says Pinder. By the time the fit-out starts, however, there’ll be upward of 60 operatives on site. Getting architects on board early is key
6 N 3 5 2 4 1 4 5 2 3 5 2
to project success, and here Bond Bryan worked with Willmott Dixon and Scape almost from the outset. “They hadn’t used it before and needed guidance,” recalls Ridley-Thompson. “So we showed them how to use the Scape grid and to employ simple rules of thumb to make sure the system worked for them.” He stresses that it’s counter-productive
Great Denham primary school 1 Main hall (double height) 2 Classroom zones 3 Entrance/admin areas 4 Courtyard 5 Corridors 6 Nursery block
to develop a design and then try to match the system to it. “With a traditional build the architect is king; they’ll design it and the engineer will model it. But if you want to get the benefits of the Scape system, you have to work with the grid and column positions. You don’t try to eliminate them to create larger spans, because then you’re having to beef up the structure, and that adds to the cost,” he says. But for the build team, playing by the rules is everything. “If you’re not getting a structural compliance with the system in excess of 80% at design stage, you’re wasting both money and design time,” says Carter, adding: ”You don’t create a
system to have architects break it — all the efficiencies are bound up in its standardised nature.” So to avoid exponential costs, the advice is: stay within the system. Nevertheless, there have been some modifications at Great Denham: where internal columns have been dropped, such as in the kitchens and servery areas where a more open plan was needed, increased beam sizes are immediately obvious. That said, Ridley-Thompson acknowledges that “the world’s a messy place and sometimes you have to make client changes, but it’s not a system that likes structural changes at a late stage”. In the time that Wilmott Dixon has
worked with Scape it says there has only been one project overrun, with none going over budget. Not everyone is pleased about this, with Building Design magazine calling Sunesis schools a “one-size fits none” approach. But the team is unlikely to be troubled: the comment came in response to a positive review by Design Council CABE of two new Sunesis schools in Rugby and the Isle of Wight. Provided there was further client/design team liaison, it endorsed them as “a successful way to build new schools”. CM
CONSTRUCTION MANAGER | APRIL 2012 | 33
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