140 THE BUILDING CONSERVATION DIRECTORY 2025 CATHEDRAL COMMUNICATIONS RESPONDING TO MOULD GROWTH Mould can grow almost anywhere in a building but there are some locations more likely than others, including bathrooms, kitchens and laundry rooms in particular. In other areas look behind furniture, paintings, tapestries and in cupboards. Generally, cool surfaces are most vulnerable, such as window and door reveals and soffits, windowsills and the base of walls. Areas that are not properly or regularly heated and ventilated are also vulnerable, as are materials which have been damaged by water, areas in disrepair, areas poorly insulated, and others. We also have to consider that in many older buildings, the replacement of lime plaster with a dense cement-based plaster that conducts heat and creates a cooler surface can also cause mould growth. In areas where there is a large quantity of mould present expertise is required to remove it. There will, however, be many circumstances, such as a small amount of mould around the edge of a bath, which should be dealt with as part of normal housekeeping. Ventilation will reduce the persistency of such high levels of RH, so air-movement needs to be checked out. Older buildings were passively ventilated with ill-fitting doors and windows providing air inlets and outlets, with open flues providing the chief means of ventilation outlets. Understanding the effectiveness of air-movement is critical. Many older buildings have been altered and some have been retrofitted to reduce heat loss. Windows which have been draughtproofed, or have been replaced in such a way to remove draughts, will now rely upon night latches and trickle vents for air inlets. Observing whether trickle vents are closed or blocked, and whether night latches are even used at all, are critical areas of understanding. Today few people use open fires to heat their buildings, and we often find that a flue will be entirely blocked, removing this excellent source of ventilation for internal spaces. Many buildings will today rely on mechanical extractor fans and the extent of complexity depends on the type of building. Where dwellings are concerned, singular mechanical extractor fans in kitchens and bathrooms are the norm. Check whether these run continuously, are automatically activated with high levels of RH, or whether they are just activated when the occupants turn them on. Not only is it necessary to know whether such extractor fans are working and in use (and often they are not), it is also necessary to determine whether they are performing properly. This is where using a vane anemometer with a hood is necessary to determine whether they provide enough ventilation. Ventilation is therefore important, but temperatures, and in particular surface temperatures, play the major role in bringing about high levels of RH. The investigator must therefore work out if a building is being heated sufficiently and whether it has sufficient means of ventilation. If there are inadequacies in these two areas, pinpointing the reasons is essential. Great care and attention is required to determine the extent to which the occupancy is contributing to the problem, and the extent to which the adequacy of the building, including its condition, could also be an issue. If the building is in poor condition, which could mean leaking plumbing or moisture ingression into the building fabric through external means, then this could result in dampness problems internally. This may also result in lower surface temperatures, which can then make those surfaces more susceptible to high levels of RH. While retrofit measures can be positive, ill-informed, poorly designed or installed retrofit measures can also cause such problems. Such failings are known to be a major factor in the rise of damp, mould and condensation issues across the UK within buildings which have been retrofitted. When conducting an investigation, the analysis continues throughout each stage but there will be a final analysis and this will lead to a conclusion on how to resolve the issues. JOHN EDWARDS is director of Edwards Hart (www.edwardshart. co.uk) and the Environmental Study Centre (www. environmentstudycentre.org). An accredited surveyor and chartered environmentalist in architectural building conservation, John is formerly assistant director at Cadw and lead author for BS7913: 2013: Guide to the Conservation of Historic Buildings. He is a trustee of the IHBC and Professor on Practice at the University of Wales Trinity St David. FURTHER TRAINING DAMP, MOULD AND CONDENSATION IN BUILDINGS QUALIFICATION A new qualification was launched in January 2025 which will focus on the issues that arise in buildings due to ill-informed changes or treatments which have taken place to tackle damp, mould and condensation. The ABBE Level 3 Award qualification in Damp, Mould and Condensation in Buildings is a government-approved Ofqual-regulated qualification. The qualification can be obtained through attending a two-day course offered by the Environment Study Centre. The course will promote a more informed approach in all different types of buildings, including older ones. As a new qualification it will also focus on some of the main issues of today. This includes the retrofit of buildings and the way we generally deal with related health issues, with particular reference to ‘Awaab’s Law’. The training course will cover the development of solutions to the problems and how to implement them. This course has particular reference to BS 5250:2021: Management of moisture in buildings, which is the British standard for dealing with damp, mould and condensation in buildings. It also includes the information contained in the document: Investigation of Moisture and its Effects on Traditional Buildings, Principles and Competencies, a Joint Position Statement published by the RICS and Historic England with others in 2022. See http://bc-url.com/dmc-training Dry rot (Serpula lacrymans) red rust-coloured spores, which are easily seen providing an indication of the quantity of spores created by mould.
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