Stationed at the edge of Chester city centre, stands Chester Castle. The history and importance of this location is perhaps no longer noticed by the hundreds of shoppers, tourists and businessmen who pass by its gates every day, but this building has played a pivotal role in the history of the UK.

Since the early 1990s, English Heritage has commissioned several phases of work to conserve and consolidate the original fabric and this project encompassed the Half Moon Tower and the Frobisher’s Workshop.

  • Client: English Heritage
  • Architect: Arrol & Snell
  • Designation Grade I Listed
  • Project Value: £200,000+
  • Services Provided: Stone Masonry Conservation, Heritage Consultancy & Surveys, Building Conservation, Specialist Lime Mortars

Stationed at the edge of Chester city centre, stands Chester Castle. The history and importance of this location is perhaps no longer noticed by the hundreds of shoppers, tourists and businessmen who pass by its gates every day, but this building has played a pivotal role in the history of the UK. The first castle, largely constructed of timber, was built on this site in 1069 by order of William the Conqueror, on top of a Roman fort overlooking a crossing point in the river Dee below. In the 13th Century, a programme of rebuilding in stone began with the earliest of these buildings, the Agricola’s Tower, which houses the chapel of St Mary de Castro with wall paintings dating from the early 13th Century. The rebuilding of the castle complex in stone was accelerated by Henry III who commissioned several of the buildings we see standing today, including the Half Moon Tower and the giant masonry defensive walling, both of which were included in one of the most recent phases of conservation work carried out by Recclesia’s specialist team. Also included in the conservation project was the rectangular building hitched onto the inner face of the Half Moon Tower, a building known as the Frobisher’s Workshops (from “Refurbisher”, where the repairs for the armoury were undertaken). Originally established as a mint in the 17th century, it is now the only brick-built building still remaining on the site today.

Since the early 1990s, English Heritage has commissioned several phases of work to conserve and consolidate the original fabric. One of the latest of these was Phase VI, wholly commissioned and financed by English Heritage’s in-house conservation funds. The project encompassed the Half Moon Tower and the Frobisher’s Workshop.

The Half Moon Tower and the Frobisher’s Workshop are the only two buildings remaining that form part of the defensive walling of the castle itself. They are joined to each other quite crudely and built using completely different materials at very different points in time. The Half Moon Tower was built using inconsistent quality of stone and the weathering characteristics change by elevation. The Frobisher’s Workshop is brick-built and failing facing bricks were covered over in the last century with a hard cement based mortar, which only exacerbated the initial problems. Both buildings had suffered unapologetic modifications to their original layout and the consequences of failing roofs. The objective of Phase VI works was to repair the external envelope of both buildings, along with internal structural work and timber repairs. The buildings are Grade I listed and Scheduled Ancient Monuments, meaning that the work had to be of the highest standard and that the craftsmen involved in the project needed to understand the conservation philosophies behind the approach to even the most minor repair. As such Recclesia ensured that all staff were provided a history lesson explaining the background and importance of the castle buildings.

A very carefully designed scaffolding was erected in September 2010, wrapping itself around the Half Moon Tower whilst standing on the steep slope of the outer bailey. The stripping of the slates and lead sheet roof areas was the first item programmed, revealing the roof timbers which were found to be in a much poorer state than originally anticipated. The joiners were then faced with a very difficult task of not only retaining as much of the original fabric as possible by splicing new to old, but doing it in a carefully planned sequence so as not to cause the wholesale collapse of the roof structure. Following lengthy discussions with English Heritage structural engineer Stuart Ellis, a design was produced for the insertion of three stainless steel supports to the roof trusses, which were fabricated off site and then expertly installed by Recclesia’s specialist metalworker Mike Batters.

As the joinery repairs began, the task of carefully removing the cement render from the already delicate 1696 brickwork beneath began. This was a painstaking process taking many weeks, and the condition of the bricks beneath was such that hundreds of individual bricks had to be replaced. Each irreparable brick was carefully cut out by hand and a new one slotted in until each elevation was sound enough to accept a new lime render coating.

Recclesia’s masonry conservation specialist Geoff Moore and architects from Arrol and Snell, carried out a detailed inspection of the masonry and a schedule of repairs required to each stone was drawn up. This included extensive de-scaling, pinning, indenting, weather-shedding, and in some areas, replacement of ashlar back to its original plane using traditional stonemasonry techniques. The masonry conservation exercise was finished by a general scheme of re-pointing using an hydraulic lime mortar.

Like most historic structures the castle will require further conservation work in time, but this phase was considered a significant and successful intervention in protecting the site.