Since at least 1990 there has been concern about subsidence on the south side of St John’s. A large building located at the top of a hill is always at risk of slippage, and the situation can only have been made worse by trees in the meadow whose roots were sucking the moisture out of the ground.
In 1999 regular monitoring of the building’s movement started. For a while, temporary measures (netting and a wooden tower) were put in place to keep people safe from falling masonry, but by 2014 it had become clear that conditions had worsened. The building was in a constant state of movement: the south side was moving up and down by 25 mm as well as in and out. The whole of the south side, including the tower, was detaching from the main building, the floor internally had sunk and fractured, and some very impressive cracks could be seen inside and out.
In January 2014, Historic England (formerly English Heritage) placed the church on their At Risk Register due to overwhelming concern about the condition of the building. Clearly something had to be done to address the damage – without remedial works, we ran the risk of losing the south side and of the church falling into disrepair.
In early 2015, work started on making applications for funds to underpin the south side, this by now being clearly seen as a priority. The project was originally costed at nearly £750,000 and a local fundraising campaign, together with successful grant applications, meant that we were able to install wooden buttresses externally in December 2015, go to tender for the contracting works in early 2016, and start work in October 2016. Work is scheduled to be complete by the end of April 2017. The scope of work has included:
- taking up the woodblock floor and floor tiles
- removing the radiators
- piling internally and externally to a depth of at least eight metres along the length of the south side
- drilling through the foundations
- pouring concrete to make beams to go through the church foundations
- positioning these beams on the piles to take the weight of the building and transmit the load
- reinstating the floor and heating system
- rebuilding the staircase to the south side entrance
These works will secure the building for future generations but will not repair the damage already done, and the church will remain on the At Risk Register – there is a significant amount of restoration work still to be completed before the church is returned to its former glory.
Progress of works
- 24 October 2016 – the contractors arrive on site and start to set up; hoardings go up externally and internally
- 7 November 2016 – the floor is taken up and excavation begins
- 14 November 2016 – piling rig on site, drilling down to a depth of eight metres along the south side and to twenty metres at the Lady Chapel end; there will eventually be nine piling locations, each with two piles externally and one internally
- 21 November 2016 – excavation under the tower
- 28 November 2016 – we begin to break through the foundations
- 8 December 2016 – children from Cypress Primary School visit the church to learn about its history and look through the viewing panels
- 8 December 2016 – a talk by our structural engineer about the work
- 15 December 2016 – more than 500 people attend the London Mozart Players and Royal British Legion joint Christmas concert and take the opportunity to find out about the underpinning project
- January 2017 – concrete works begin; metal cages are inserted in the holes in the foundations and concrete is poured; these beams will sit on the piles and take the weight of the building
- 30 January 2017 – once the concrete has cured (dried), it is drypacked, which involves pouring a mixture of very strong concrete between the beams and the building’s foundations; this mixture will now transfer the weight of the church to the new foundations provided by the piles
- 6 February 2017 – backfilling begins
- 6 March 2017 – the floor is prepared for relaying of the tiles and woodblock
The ‘St John’s: securing our foundations’ project has been supported by a grant from the Heritage Lottery Fund. Thanks to National Lottery players, we have been able to halt the subsidence of the south side and save the building for generations to come.
And thank you to all our funders in helping make this happen.