The Incident

A switchgear failure inside a UK Power Networks substation in Hastings caused an explosion in June 2018, resulting in superficial damage to sandstone, brickwork and wooden sash windows of the adjacent Grade II listed former Victorian school building, which is converted into residential dwellings.

The impact on the building needed closer inspection and the initial walkover identified splatter/scorch marks on the brickwork adjacent to where the fire had been and blackening of the sandstone around the first floor window immediately above the substation. Paint was badly flaking from the window frames. To inspect the damage more closely, scaffolding was arranged to assess the extent of damage.

The Solution

As this is a listed building, advice on permitted works was sought from the local conservation officer. Our suggested technique was to avoid the need to remove any of the masonry. This involved employing a specialist masonry cleaning company to use the Historic England recommended Doff Steam Integra System, a low-pressure steam clean to remove surface stains without damaging the sandstone and old brickwork, using degreaser to lift the staining from the masonry. After the masonry clean, scaffolding was erected across both properties to allow for further assessment and restoration works to the window frames. There was extensive impact to the window putty which had dried out as a result of the heat from the fire, which also allowed damp ingress during the winter. Both windows were sanded back, re-puttied, filled and painted.

The Outcome

All the staining and superficial fire damage was successfully removed from masonry. The wood window frames were restored to the satisfaction of both affected homeowners.

Gaps around the window frames were filled in to prevent further damp issues in the future. Significant cost savings for the client were achieved as our approach avoided the need for either masonry or window replacement.

Below are some ‘before’ and ‘after’ images.