Conservation of Orford Castle

A £1m conservation project has taken place to help protect the much-loved 12th century Suffolk landmark Orford Castle.

The project saw a layer of lime render applied to the outside of the keep - following 13 years of research, trials and consultation to find the best way to protect the castle’s deteriorating external walls and delicate stonework from the elements. The castle walls were constructed almost 1,000 years ago using a delicate local mudstone, known as 'septaria' which has been deteriorating since the 16th Century.

A detail of a 16th-century chart of the Suffolk coast. Orford Castle is depicted and named

A 12th Century Royal Castle

First built for King Henry II between 1165 and 1177, Orford Castle was once a royal outpost on the River Ore’s tidal estuary, in Suffolk. All that remains of the outpost today is the Castle Keep. The castle’s curtain walls, outer towers and gatehouse were demolished in the 17^th and 18^th centuries. Constructed with brown septaria, a crumbly mudstone once seen as a good building material and found in local estuaries, the stone has over time become brittle leading to the castle’s deterioration. Research indicates that this deterioration has been underway as early as the 16^th century. There have been numerous attempts historically to prevent it, including engravings from 1738 which indicate attempts to reinforce the Keep.

Before the conservation project, there were visible indications of the crumbling septaria, and the immediate area around the base of the castle had been fenced off for decades.

You can find out more about Orford Castle's history here.

Conservation Trials

In order to identify the best approach to Orford Castle’s long term care, English Heritage had been conducting conservation trials since 2008, these trials focused on three different forms of intervention. Findings from the 2008 works (alongside examples of earlier and contemporary septaria projects at Framlingham Castle, Erwarton Church and Colchester Castle) informed a further series of trials carried out on the west face of the north turret in June 2017. An assessment by the Historic England Conservation Committee, and a final trial was conducted in summer 2019.

Over a decade of research and trials concluded that it was neither possible or practical to replace the stone on a like for like basis and alternative methods of conservation had to be considered. This was partly due to the difficulty in obtaining septaria, a process which would involve the detrimental environmental impact of dredging estuaries, but also due to the poor attributes of the mudstone for construction.

A drone shot from above the height of Orford Castle; far beyond the castle, a strip of sea is visible in the background.

This 2018 drone shot shows how far the sea is from the castle now; here, it is just visible in the background

Conserving the Keep

With the findings of all these trials analysed, and with support from Historic England, English Heritage undertook a project to add lime render to the facing of the Keep, working alongside leading historic building conservation professionals.

Trials indicated that while the lime render will initially appear light and creamy in colour it will deepen and darken over the years making a closer match to the septaria. While the render will change the Keep’s appearance, the expert consensus is that this approach represents the best outcome for the castle over the longer term. The works also mean that for the first time in years’ visitors have access to the grounds around the castle, which due to the crumbling septaria, were fenced off.