The big surprises on Jon Allworth’s refurbishment of pre-Victorian council offices as a three-storey museum and gallery were not so much the unknowns in the ground and the existing building – although plenty of those turned up – as the inability of specified products and procedures to meet their brief. Demonstrating all the flexibility and pragmatism of the experienced construction manager, Jon responded with technical panache to find alternatives that worked and overcame the setbacks.
When the structural engineer’s underpinning design to support the plant room in the new, hand-excavated, 185sqm basement proved flawed, Jon pumped 30 cubic metres of concrete into the basement as a platform for temporary props while the subfloor works were carried out. It did the job, and was cheaper and six weeks faster to boot. When the timber flooring selected by the architect for the gallery in the basement exhibited insufficient tolerance, he put in a subfloor to compensate.
When the insulation product for the Assembly Hall ceiling proved unsatisfactory, his discussions with two roofing contractors alerted him to the technique of blowing ‘candy floss’ insulation into voids. Not only did it work, it also meant full access to the roof was unnecessary. And when the lime putty plaster for roof repairs turned out to have a far longer drying-out time than modern products – 25 days rather than just one – he prioritised the affected areas, carrying out the work earlier than originally planned.
His ‘leave it with me’ response for issues where he had no immediate solution was a huge reassurance for the client, given his speedy return with an effective workaround. He was the embodiment of ‘can do’. With modern services unable to be hidden in the building’s ceilings or floors, he found ingenious cable and pipe routes, including through heritage chimneys and fireplaces.
He won over the professional team, initially sceptical of his new construction approaches. And his relationship with the client was superb. Dismissing the intended new Assembly Room ceiling as a far inferior version of the previous ornate version, he drove a spectacular redesign, arguing that it would help event organisers selling the space to draw in much higher revenues, and coming to the rescue of the challenged project budget by going 50/50 on the cost.
Understandably thrilled by this – not to mention Jon’s patient and personal hosting of VIP and press visits helping raise nearly £1.5m in match funding – the client has awarded Willmott Dixon £30m of further contracts.