30 THE BUILDING CONSERVATION DIRECTORY 2024 CATHEDRAL COMMUNICATIONS to commence. Until then it will provide discreet and hopefully adequate protection against collapse for both the building and the general public. MORE ON SAFETY NETTING Safety netting has been effectively used as both a temporary and more permanent protective measure in a variety of situations where fabric detachment and collapse are a risk. Examples in secular buildings include the rubber brick decorative frieze of a Grade II building in Carlos Place and the high-level decorative brickwork of Grade II Claridge’s Hotel, both in London. Netting has also been effectively used in the protection of ruins in archaeological sites, such as the Thermes di Caracalla in Rome, Italy. As these cases demonstrate, choosing the right colour of netting is an important element of the specification. Green netting is certainly far too prominent and detracting from the character and appearance of historic buildings, as seen in the case of the Grade II listed Eaton Chapel, in London. Netting installation does not need to involve the use of a MEWP. It is possible, in some circumstances, for it to be carried out by specifically trained abseilers, an option which may be more economical when compared to the use of a MEWP. However, this option excludes the possibility of close inspection and consultations with other specialists which was deemed important in the case of St Mary’s. Even so, in the case of St Mary’s, yearly condition inspections of the netting would most probably be carried out using abseilers. THE VALUE OF DRONE PHOTOGRAPHIC SURVEYS Safety netting installations tend to be intermediate protective measures which are taken in response to risks identified through inspections. Returning to St Mary’s, had the original collapse of the two strings on the south facade not taken place, a close inspection of the condition of the tower and spire stonework may not have been instigated. This is a situation which is not unique to this church. The detachment and collapse of masonry fragments in places frequented by the public is not a rare occasion. Examples of unexpected stone collapses leading to surveys and extensive repairs include notable ecclesiastical buildings such as Wells Cathedral, Canterbury Cathedral and York Minster, to name but a few. It is also a situation which does not apply to churches alone as the secular examples of Carlos Place and Claridge’s testify. With regards to close inspections, the value of drone photography should be acknowledged. While close inspection using MEWP is inevitable in some cases, the experience at St Mary’s has highlighted the value of photographic drone surveys. When systematically approached they can provide a quick and economical way to document, evaluate and monitor the exterior condition of historic fabric, which is invaluable. More to the point, it might be a good idea for drone photography to form part of the quinquennial inspection of churches financed by the diocese, particularly where highly decorative stonework adjoins streets and other places frequented by the public. BIOLOGICAL GROWTH AND ITS EFFECTS The survey of the roof of St Mary’s from the MEWP also assisted in establishing why the walls of the stairwell to the tower were saturated, as it was an area of the church envelope which until then had been difficult to inspect. It confirmed that missing render fillets between the stairwell roof and the adjoining church wall had allowed water to pool, with the water ending up draining into the wall below, and enabling the growth of buddleia. These plants need to be eliminated by proprietary chemical means before their roots cause any more structural instability and to allow the masonry to be repaired. Further Reading Historic England, Kent, Building Stones of England, pp 17–22/36 Historic England, Bristol, Bath and Surrounding Areas, Building Stones of England, pp 37–39/45 David Watt, Managing Biological Growth on Buildings, Historic Churches, 2006 www.strongholdpreservation.com www.gmsafetynetting.co.uk/debris-nettingon-fragile-stonework ELENI MAKRI MA(Cons York) BArch, ARB, IHBC, AABC is the Director of Conservation PD (see page 15) and church architect for St Mary’s Hornsey Rise. Her previous roles include head of the heritage team at the Halpern Partnership (now Formation Architects) and local authority conservation officer. Claridge’s Hotel, London, showing the netting of the high-level brick cornice (Photo: Stronghold Preservation, 2013) The green netting of St Peter’s, Eaton Square detracting from the character and appearance of the historic building (Photo: Eleni Makri)
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