Northern Curtain Wall, Carisbrooke Castle Isle of Wight

Oxford Archaeology was commissioned by English Heritage to undertake an historic
building watching brief at Carisbrooke Castle on the Isle of Wight. The investigation was
undertaken during the conservation of the outer face of the northern curtain wall as well
as the Keep, and it was principally intended to record a number of exposed areas of the
wall core where small voids had opened up by parts of the wall face coming away during
the repair works.
The wall is generally constructed from rubble but there are some areas of larger coursed
blocks and some areas have a flint face. Numerous phases of repair to the face are
apparent including areas where a cement render has been applied over cracked former
facing stones and then with small stones embedded in the render. Even in these areas the
former facing stones are rubble rather than large ashlar blocks. In some areas this cement
repair has come away to expose voids behind.
In the voids exposed the wall appeared to be of poor construction with loose rubble fill,
relatively little mortar to bond it and numerous hollow patches. The voids and poor
quality of the wall has allowed ivy and other vegetation to penetrate deeply into the wall
and this has further weakened the structure. The deeply set mortar generally appears to
be an ochre colour lime mortar but the shallower part of the wall (c.15 cm into wall) has
a white mortar.
The recording was not intended to produce a comprehensive survey of the wall but a
number of other features were noted including many putlog holes which would
historically have been used to erect scaffolding against the wall, a substantial vertical joint
and other evidence of different phases of construction. Although the recording was small
scale in nature it has added to our overall understanding of the historic structure.
The main recording focussed on the northern curtain wall rather than the Keep because
this was the area in which the voids were exposed.