Past & Present Work

Project: The Investigative phase of the Sacrarium Cosmati Pavement, Westminster Abbey.
Client: The Dean and Chapter, Westminster Abbey.
Head Conservator: Vanessa Simeoni.
Date: 2003 - Ongoing

History
In 1268 as part of a large scale rebuilding of Westminster Abbey, Henry III commissioned two Cosmatesque pavements. One in the Sacrarium and the other in the Shrine to St Edward. Both these pavements are superb examples of opus sectile floors and are the only surviving floors of their type north of the Alps.

Opus sectile, meaning cut stone, is a form of mosaic decoration dating back to antiquity. The Cosmatesque style comes from the Mediterranean and was popular in the twelfth and thirteenth centuries as an extremely intricate and elaborate decoration of floors and tombs. Valuable semi-precious stones of religious significance such as porphyry and coloured marbles were recycled from Roman ruins, cut into tiny tesserae, and laid out in mesmerising repeating patterns.

The Great Pavement of the Sacrarium alone is made up of over 50,000 pieces of semi-precious stone and glass. As a whole the Cosmatesque work at Westminster Abbey has survived almost eight hundred years and is now arguably the finest example of original Cosmati work in the world. This is a large and very complex project, which incorporates many disciplines and experts. The first phase of investigation and initial research has been completed and specifications for the conservation treatments have been written. Phase two will start in the near future.

The Project
Phase one of this multi-phase project was primarily investigative, looking at ways of preserving the Cosmati pavement in the Sacrarium and writing the specification for any conservation treatment necessary. As a result of careful and thorough research, a whole programme of works that incorporates other disciplines such as archaeology and academic historical research has now been devised and a full specification written.

Working alongside the conservator at Westminster Abbey and on occasion using external expertise, the following trials, research and documentation were carried out:

Full analysis of all material in the floor, including modern surface finishes.

Full survey and provenance of all stone and glass

Full survey of all mortars, including more recent cements

Research into ancient stone cutting and polishing techniques.

Extensive trials and research into stone consolidants

Extensive trials and research into cleaning the pavement, including laser

Ground Penetrating Radar survey of the floor to assess the underlying layers.

Grouting trials for the stabilisation of the sub-structure

Design of a versatile digital documentation package using CAD to document the project with a view to publishing the work electronically

Manufacture of new glass to resemble the original

Making of new lime mortars to match the original mortars

Cutting new tessearae and Purbeck marble following the ancient techniques.

Westminster Abbey

The Sacrarium Cosmati Pavement

Detail of pavement before cleaning showing various historic repairs

Close-up of tesserae and mediaeval mortars

Detail of 13th Century glass