Structural rebuilding of a Norman Motte & Bailey Castle

Over the years Canterbury castle had had many years of damaging intervention, although the ragstone and knapped flints may have withstood the harsh cement pointing in places, many of the Caen details had deteriorated extensively.

We set up some temporary support to the window head using an acro and strong-boy, to remove the stone jamb, we first had to complete the remedial work to the RH side to prevent risk of undermining the flintwork surrounding which had little embedment back in the substrate.

The original stones were heavily tooled; we recreated this surface finish on the new stones we fixed. This was done by hand using mallet and bolster chisel.

The original joints had weathered significantly, but some sheltered areas showed joints as tight at 3mm. Using well graded sand we replicated these joint widths in our rebuilding works.

The fine jointed Caen were bedded and pointed with a lime putty and Pozzolan mix, this included a bath stone dust to colour the mortar closer to the natural stone colour.

The flints and replacement ragstone were bedded and pointed in a very coarse pea shingle; local sands mix. Aggregate size was 10mm pea shingle down to a fine silica sand. The binder specified was NHL 2.

Replacement flints and ragstone were sourced from local quarries and where possible original fallen material was reused.

A challenge of this work was achieving deeper embedment than the original which had laminated from this shuttered/poured core