Westminster Healthcare: St Mary's Nursing Home

Structural Report on St Mary's Chapel: September 2001

General

This report follows a recent visit to the site with the purpose of investigating the feasibility of rebuilding and refurbishing the St. Mary's Chapel.

Historically, the Chapel was originally constructed by the pupils and teachers with materials either sourced or donated from local sites. The methods of construction were simple with little regard to recognised design practices which have manifested themselves in the current unstable condition of the building.

Foundations

The foundations are not adequate to support the loading of the external walls and roof. They have not been designed or constructed using recognised methods, resulting in the settlement of certain areas of external wall.

External Walls

The external walls are constructed using a mixture of reclaimed clay bricks, tile and presumably local stone. They have been constructed in uneven coursing with inadequate bonding technique resulting in poor load bearing capabilities. There are many areas where it is evident that the walls have been unable to withstand the roof loadings and have bulged out from the vertical causing cracking and structural instability.

Roof Structure

The main signs of structural failure have occurred within the roof construction. Large timber members have been used in a traditional rafter and purlin designed structure, however it appears that insufficient lateral restraint has been incorporated and the roof has slowly settled and splayed collapsing in on itself with insufficient support from the timber columns. The external walls have in places been pushed outwards by the forces on the wall plate which itself has raised and twisted approximately 100 mm off the supporting brickwork as the structure falls inwards. Extensive areas of the timber members show signs of woodworm infestation and, even though I have not carried out any detailed examination, the structural integrity of the roof timbers generally could well have been compromised. The roof has therefore settled in many places and twisted with the tiled finish following the contours of failure. The roof has had to be artificially supported by steel props over the last five years which has arrested the rate of decline, but are without doubt the only reason that the whole roof structure has not finally collapsed within itself

Summary

The absence of suitable design constraints and inadequate methods of construction are apparent throughout the building. Its construction will not allow for repair or refurbishment to current acceptable constructional standards as a habitable building and there are great fears from a Health and Safety point of view that anyone now entering the Chapel would be in danger from the collapse of all or parts of the roof and external walls. All services have now been disconnected from the building.

It is my opinion that due to the flaws in the original design, selection of materials and methods of construction the Chapel building is near to total collapse and should be safely and sensitively dismantled, whilst recognising the historical significance and sentimentality attached to the school.

The Health and Safety implications of allowing the building to continue to deteriorate must not be underestimated.

C. DIXON Estates Manager - Southern Region

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