During an earthquake a large piece of cornice broke away from historic Mosborough Hall in Sheffield, England. It was restored using reconstructed stone.
Step 1
After cleaning up the exposed stone using a mallet and chisel to chop away any loose stone and wire brushing any remaining dirt and dust, the stone is drilled in several places and brass dowels inserted into the drill holes.
The dowels are then strung together with copper wire, this acts as a rust proof reinforcement. Following this a scratch coat of reconstructed stone is applied using a trowel.
Depending on the depth of the repair, one scratch coat may be sufficient, however on this particular repair several coats were required. Each coat must be applied only once the coat below had dried.
Step 2
The cornice is built out with each coat, once it is at the surface the reconstructed stone is shaped using a mixture of trowels, floats and straight edges followed by a final rub over with a sponge.
While the reconstructed stone is still soft, traditional heritage style batton marks may be applied using a teeth tool or markings matching the existing stone can be applied using trowels, or chisels.
Step 3
The repair will weather the same as natural stone does. Once the reconstructed stone repair has set, colouring in can take place to accelerate the weathering effect and blend the repair into the surrounding stonework.
Step 4
The left hand side of the right hand mullion also being restored.
The finish is a seamless blend of the restored and original stonework.