Canynge Square Sinkhole

Jan 2, 2021


The appearance late on Christmas Day of a very deep hole in Canynge Square gardens has caused the Square to become Clifton's most popular tourist attraction.

The fissure opened at about 22.30h. to reveal some masonry arches which had apparently failed, collapsing into the void below so that the mature Japanese Pagoda tree growing above fell into the resultant sinkhole. The response of the emergency services was reassuringly prompt and efficient, despite it being Christmas evening. The question everyone is asking is what had caused this to happen.

CHIS's architectural adviser, Michael Woodman Smith, a conservation architect, lives in the Square and has done some research into the history of the site. It seems that when building started here in the early 1840s much of the stone used was quarried from what are now the Square gardens and also from where the houses abutting Canynge Rd now stand. In order to fill in the quarries a series of interconnected vaults were constructed, made of local rubble stone with masonry arches, capped with about 1m of soil.

There are records of parties taking place in the vaulted spaces under the north side of the Square and also of their being used as wartime air raid shelters. Before the advent of mains water there might have been a communal water cistern here.

Michael considers that a measured survey of these historically important spaces beneath the present day landscaped gardens, and possibly the roadway, should urgently be made. It would seem likely that these vaults are physically attached to the listed houses on the north, and possibly some on the west too, and may well themselves be listed.

The probability is that the roots of trees planted in the soil above the vaults have penetrated the vaults causing structural damage which led to this collapse. There is at least one other mature tree nearby which is already leaning at a dangerous angle.

It is known that the mains gas, water and electricity services run beneath the road and further structural movement or collapse might cause one or more of these mains to fracture, potentially causing serious damage to both people and property. It would, therefore, be prudent to take immediate temporary action to prevent this happening.

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