The engineer requires that we inspect the wall foundations. Feeling a bit uncomfortable about disturbing something that has stood for so long, with out any sign of subsidence or failure, we carefully excavate trenches along the walls.
The solid stone external walls are 60cm wide, the front and rear walls are built along the on top of solid rock slabs that run across the site east to west. The end walls run over the tops of other slabs rising across the site and are built down in to the v-shapes that are formed where the stone had been quarried out. Built on solid stone it is no surprise the Chapel shows no sign of any movement. Following the engineers advice we pack the foundations with stiff fairly dry mortar and refill the trenches. So all the hard work is covered up!
The two internal walls are not of such solid construction and perhaps were added at a later date, as they are only keyed into the external walls in few places and just on a foundation of a thin lime mortar bed over tightly packed small stones and soil. Rather than trying to underpin them, we decide to remove them and replace them with steels to support the floor above. The two steel beams discussed with the engineer became 2 beams and 2 columns when when the engineer did the full specification, so a little more complicated than we had at first envisaged.
Deciding to remove these walls, led us to make significant changes to original planned layout and the need to return the Building Control for approval of these changes.