BUILDING CONSERVATION OF CATHEDRAL TOWER

Christ Church Cathedral Tower dates from c1225. The Cathedral welcomes around 450,000 visitors per year and is open daily for worship and prayer. The College is also open to the public every day with the tower being visible from within the grounds.

Fragments of the tower’s interior plasterwork were found on the Cathedral floor. A survey carried out by Ptolemy Dean Architects identified failing plasterwork to the upper areas of the internal tower to the Cathedral crossing. Damp to the tower walls caused by moisture trapped beneath the dense cementitious pointing applied in the 1960s was also discovered.

Cliveden Conservation was invited to tender and was awarded the works to undertake the building conservation work which included internal and external repairs to the tower.

Plaster Conservation Work
A complex birdcage scaffold was built to conduct the internal works. Cliveden Conservation worked in close collaboration with the Cathedral and College to minimise disruption.

Conservators investigated the stability of the plasterwork before it was consolidated. A hot-lime mix was used for the new plasterwork to match the original fabric. Five coats of limewash in a hand-mixed colour using natural earth pigments were applied to the entire area to match the adjacent limestone.

Conservators cleaned and waxed the historic timber ceiling of the former ringing chamber.

Stone Conservation Work
Externally, extensive removal of hard cementitious mortar exposed the original rubble stonework.

Following analysis and consultation with Ptolemy Dean Architects, a hot-lime sharp sand mortar mix was designed and deep repointed. The mix was brush beaten to thoroughly tamp the mortar into the joints and to expose the aggregate.

Conservators surveyed and hand-cleaned the stonework to remove carbon deposits. Consolidation and mortar repairs to sky-facing surfaces and water traps to the later Gilbert Scott stonework were undertaken. In some areas, skilled stonemasons replaced dressed stonework with new Hartham Park Bath Stone.

Ironwork Conservation
Scott’s original structural ironwork was repainted.

Results
The six-month programme of building conservation work undertaken by Cliveden Conservation’s team in collaboration with the Christ Church College and Ptolemy Dean Architects has safeguarded the future of Christ Church Cathedral Tower.

The cementitious pointing which was causing damp in the walls has been removed and the external elevations repointed. The Gilbert Scott’s structural ironwork has been repainted.

The conservation team successfully consolidated the failed plasterwork and have redecorated. Recovering the historic internal stonework with new limewash in place of a previous harsh white has transformed the appearance of the tower.

Expert project management resulted in minimal disruption to the Cathedral and College. Works were completed on time and within budget.

Heritage Skills Training
Cliveden Conservation is committed to filling the heritage skills gap with training programmes and apprenticeships. Their stonemasonry apprentice George Place spent several months working on the conservation of Christ Church Cathedral Tower, honing his skills and completing part of his on-site assessment during his tenure.

Cliveden Conservation hosted visits from students in Building Conservation (Oxford Brookes) and employed two of their students in a labouring role, working between lectures.