Ditchley Park
It is great to see the progress being made on Ditchley Park Rotunda, with the repairs now well underway. Ditchley park, near Enstone, functions as an internationally renowned conference venue. The owners, The Ditchley Foundation, are keen to maintain the structural integrity of the Rotunda’s existing historic fabric, ensuring that it can remain a functional space.
The Rotunda is a Grade II listed building, designed in 1760 by Stiff Leadbetter for the Earl of Litchfield and is the principal focal point at the end of the lake. It is traditional in style and built from limestone ashlar with a solid rear wall and ionic colonnade, supporting a heavy entablature and leaded dome. Underneath the structure there is a tunnel leading to an undercroft. SOLID were initially engaged in 2019 to undertake a structural inspection of the Rotunda. We discovered that there were more structural issues than initially thought, so we advised to keep the area closed off to the public until repairs could be completed.
Our inspection found that the earthen floor of the undercroft was in poor condition, likely the result of animal activity. As a result it was unsafe to use and also raised concern for the stability of the walls. We proposed the introduction of a gate to the entrance of the tunnel with a solid bottom panel and a limecrete slab to the floor of the tunnel and undercroft. The implementation of this will restrict access and therefore prevent further animal activity and stabilise the base of the walls.
There was a significant amount of mortar loss to the tunnel walls and roof due to water ingress through the earth access ramp to the first floor. We specified that the walls should be sympathetically repaired and repointed in lime mortar. The issue of the water ingress needed to be addressed to prevent further water damage. It was decided the least intrusive approach, with respect to the historic fabric of the structure, was to introduce an impermeable membrane and drainage layer over the tunnel structure, hidden within the access ramp. Rainwater run-off would then be collected and discharged via a French drain away from the structure, in line with SuDS principles.
Water ingress was also the cause of underlying problems to the first-floor podium. Standing water was causing the deterioration of the floor finishes and decaying the timber floor structure. SOLID’s inspection identified several decayed joist ends. We proposed that the floor finishes be recorded and carefully removed temporarily to allow access to the timber structure for repair. In keeping with conservation principles, we decided that to minimise the introduction of new timber the floor joists could be displaced outwards, because of the curved nature of the building, and the decayed ends removed. In adopting this approach, only 3 new joists were needed.
The arches to the ground floor of the Rotunda, showed signs of movement and mortar loss, caused by rust jacking of embedded ironwork. These will be carefully dismantled and reassembled to their original line. There will also be general masonry repairs and repointing, including the careful removal of previous concrete mortar repairs.
SOLID are providing a comprehensive service for this project including surveys, repair specifications, applications, and site visits during construction. We are looking forward to sharing more photos as we near completion and will keep you updated on the work involved.
If you have a project that requires sympathetic repairs in keeping with conservation principles do not hesitate to contact the SOLID team.
