STONE CLEANING AND MASONRY REPAIRS 

Project Overview
Exeter College Library is a Grade II-listed building designed by the architect Sir George Gilbert Scott. It was built in the Gothic Revival c.1856-7 from Bath stone with extensive carved stonework. Beard Construction sub-contracted Cliveden Conservation to conduct internal and external stone cleaning trials. The scope of works included the repair of masonry to the main elevations of the library, including replacement carvings.

Summary of work carried out
Once Cliveden Conservation had full access to the library’s main elevations to inspect the stone, the condition of the stone, particularly to the dormers and library gables, was found to be in a poor condition. Cliveden Conservation worked with the project team to review the scope and specification of the tendered works.

Conservators conducted cleaning trials to inform methodologies for cleaning the internal and external stone. Cliveden Conservation used a combination of ThermaTech steam cleaning for the elevation stonework and poulticing for the decorative and carved elements. Other techniques used included latex poulticing for the internal window traceries within the annexe and library.

Masonry repairs and replacements involved work to the copings and stringcourse to ensure improved weathering protection of the elevation stonework. Cliveden Conservation also installed a new solid masonry wall and arched entrance to the link building between the annexe and the library.

The change in the scope of work and the build of the new wall and arched entrance resulted in the requirement of large quantities of stone for the masonry replacements. Cliveden Conservation had to overcome the logistical challenges of the site location in a busy city centre and the limitations of a small compound for storing materials.

To provide a solution, the project team formatted a supply schedule to sequence deliveries with the programme of work. The supply schedule provided an effective solution to minimise the on-site materials, and the supply chain corresponded with the work’s progress.

Where possible, for more minor indent repairs, scrap stone from the dismantled link building was used to reduce the amount of stone required for the works, the number of deliveries and the carbon footprint.

Programming and sequencing of works ensured the project team could complete numerous areas simultaneously. This best practice increased the team’s productivity on site and enabled the changes to the scope of work.

Consistent and clear communication with the supply chain and the main contractor was imperative to the project. Regular site meetings ensured Cliveden Conservation could coordinate their work around other trades and a busy work site, particularly for the additional internal stone cleaning and repairs towards the end of the project.

Results
Cliveden Conservation delivered excellent quality work on the masonry repairs and stone cleaning inside and outside the building. The project team achieved outstanding results in the cleaning and repair of the architectural tracery within the library.

The project team managed numerous changes to the work programme and completed them within the given timeframe with minimal disruption to the college, the city’s infrastructure and other trades working on site. A good relationship has been built with the main contractor Beard Construction and Oxford University, with both parties acknowledging the quality of our work and giving positive feedback.

Image credit: Will Pryce