88 THE BUILDING CONSERVATION DIRECTORY 2025 CATHEDRAL COMMUNICATIONS triggers can be external, such as blocked rainwater goods backing up and saturating the local masonry, invasive vegetation like ivy becoming established within the joints compromising the bonding, or structural movement caused by shrinkage of subsoils due to trees taking up more moisture. The triggers can also be internal, such as the corrosion of ferramenta cramps and other ironwork embedded in the masonry blowing the stonework. Historic repairs and interventions are potential triggers if the specification is a poor match for the existing stone type, bedding or fixing method, or if an inappropriate mortar mix is used, resulting in differential weathering of old and new, and associated failures. These triggers, when not observed and attended to in a timely manner, have a very significant impact on the condition of the historic fabric. STAVE OFF DECAY BY DAILY CARE William Morris’s plea ‘to stave off decay by daily care’ is essential to stay ahead of external triggers, addressing them as they arise. Understanding the nature of stone decay, ensuring weathering details are functioning, identifying vulnerable fabric and monitoring the rate of change are key to the care of historic masonry structures. This knowledge then informs the maintenance plan and programmes of prioritised work to conserve and repair the built fabric and ensures that the structure is dressed appropriately for the weather with a good ‘hat, boots and coat’! Periodic condition surveys of historic buildings and sites are the mechanism heritage specialists, architects and surveyors have for recording the current condition of the fabric. The survey should assess the rate of change, appraise the likely root causes of the change, recommend further investigations and monitoring, and prioritise programmes of works. Condition surveys are normally undertaken from ground level and from safe, accessible vantage points using binoculars. A current snapshot of the fabric appraised against historic survey reports and record photographs provide the inspector with that overarching understanding of building performance. Greater knowledge comes from having good high-level access to the fabric. Using a drone with a skilled operator is beneficial but nothing really compares to physical access of the fabric provided by scaffolding, mobile elevating work platform (MEWP) or through a specialist rope access team. The cycle of inspection for places of worship in the UK is generally every five years, following the principal of the Inspection of Churches Measure 1955 (amended). The statutory bodies like English Heritage and Cadw carry out a four-yearly cycle of inspection for properties and heritage assets in their care. Provided site specific recommendations for specialist surveys and programmes for structural and environmental monitoring are enacted, these periodic cycles for surveys is reasonable. The value of the same Masonry with a relatively high surface area and a high degree of exposure is particularly vulnerable to the gradual attrition by wind-driven rain, hail and whatever else the wind carries. Above, vegetation blooms in the eroded mortar joints of a buttress and right, much of the fine carving has been lost from this 19th century finial at Exeter Cathedral. heritage specialist undertaking periodic surveys should not be underestimated when it comes to appraising the rate of change to historic fabric. Where that rate increases significantly then so too should the frequency of inspections, leading to annual inspections of exposed stonework in poor condition. This may reveal the need to undertake holding and local repairs immediately, by rope access or a cherry picker, to safeguard the fabric until working access is available for a comprehensive programme of works. Undertaking major programmes of conservation and repair to stonework of historic buildings is often on a scaffold cycle as the cost of providing temporary working access at height is significant and so you make the most of the access while in place. In parish churches the interval between scaffold lifts is generally 25 to 30 years for more accessible low walls and 50 to 75 years for the more challenging high-level masonry of the clerestories, towers and spires. But, it is that high-level stonework that is most exposed to the weather and likely to be decaying at an accelerated rate. A philosophy of repair and conservation should be adopted by all interested parties, including approving bodies and masons, in advance of any works. The philosophy should be based upon the premise that as much as possible of the early fabric should be retained, that intervention in the structure is kept to a minimum, and that alterations should be made only
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