This chimney was on the same beautiful building in Macclesfield which we discussed in the post on rebuilding the brick reveal and archways. The building had unfortunately been damaged by misguided attempts to repair it using modern building materials and techniques.
The brickwork had been painted using modern paint. This was preventing the building from “breathing” – i.e. moisture had become trapped in the wall under the paint, rather than being able to evaporate harmlessly away when the conditions were right.
Once the paint had been removed, we could assess the extent of the damage. Sadly, the building had been re-pointed using cement based mortar. Again, this is totally unsuitable for an old building, as it does not allow the building to breathe.
Water had got behind the paint and frozen, causing the faces of the bricks to disintegrate. This made the chimney structure weak and unsafe.
Thus the use of the wrong materials had caused very significant damage to this building.
However, we were able to remove the inappropriate modern paint, rake out the cement mortar and benching, and re-build using lime mortar. The chimney is now restored to its former glory and should be good for another few hundred years!