We’re helping South Hampstead Junior School transform two of their 19th century load bearing masonry buildings into highly improved quality teaching space for students by September 2024 – removing heavy loads, improving circulation, and delivering remedial repairs and improved playground facilities.

Working with architects Sarah Wigglesworth and IID Architects, RCDC MEP Engineers Potter Raper Project Managers and Eden London Contractor, Civic Engineers were appointed as structural engineer at RIBA Stage 4, taking over from a previous structural engineering firm and rapidly getting up to speed with the rest of the design team.

At No 5 Netherhall Gardens we are removing three key structural walls at upper ground floor level to turn four existing rooms into a single school hall for children to collect for lessons, assemblies, indoor sports and lunch; and are engaged in remedial works to give the building a helping hand into the future.

At a nearby site, No 12, we are developing a proposal for additional teaching space via a vertical extension into existing loft space. Key is to develop an alternative proposal from the previous engineer to reduce construction costs. This looks to reuse as much of the existing ceiling joists and rafters as possible, and integrate this into a construction sequence that removed the need for a costly temporary scaffolded roof.

The No12 site has experienced some challenges: excessive ground movement and settlements have caused cracks to appear in the building. We worked closely with geotechnical specialists CGL who carried out a number of ground investigations and found the building is sitting on desiccated clay which is affected by nearby tree growth. Previous remedial works were limited in success and we are working closely with the school and CGL to develop a robust strategy that allows for adding extra load due to the vertical extension.

Responding to this, we have designed a suite of remedial measures to repair cracks in the building and provide strengthening to the existing structure. This has included introducing floor strapping and elbow ties to help strengthen the building in the case of future movements in the ground.

Sam Harland, associate director in our London studio, commented: “It’s essential we take a retrofit first approach to meeting the demand for more capacity in the UK education sector. We’ve had to move quickly to get this actioned before the new school year, while being sensitive to the historic nature and limitations of the site. In one building, we are vertically extending into existing loft space to provide more classroom space, and have developed a suite of remedial measures to breathe new life into its twin building across the road.”

The works to No 5 are being carried out within an extremely tight timeframe with all the construction works to be completed within 14 weeks, over an extended summer period, ready for the pupils to return in September 2024.