Quoins are the corner stones that hold a building together, and when they drift away from the wall, it tells you the fixings and bedding behind them have failed. Here, some had moved around 10mm and the worst overhung by 30 to 40mm. The repair had to be done stone by stone, with as little disturbance to the rest of the building as possible.

We started on the right side. Because we were taking the quoins out down to ground level, we propped the masonry above before anything came out, and numbered and marked every quoin so that each one would go back into the exact place it came from. To release them we drilled out the mortar with an SDS drill rather than hammering and chiselling, which would have been far too brutal for the building. Reducing shock through the wall was the priority.

Once the quoins were out, we cleaned them and sprayed down the dust. We then ground the top and bottom face of each stone so the new mortar keys into it and holds it in place, and we set wall ties into the bed as an extra precaution so the quoins can't creep away again.

Before re-bedding, we mixed the mortar to match the original as closely as we could, so the repair blends in and there's no visible colour difference. The quoins went back in their marked positions and were left to set. Only then did we take the props out, drill out the next set of quoins and repeat the process. We then did the same on the left side.

While we were up there, we also replaced a handful of slates on the roof that had broken and were falling down, so the roof was weathertight as well as the corners being secure.

The job went in at short notice and was carried out through poor weather. The result is a set of quoins that sit tight to the building, are tied in for the long term, and look like they were never touched.