or rubber single ply waterproofing or a GRP based liquid applied coating. Today, built-up RBM (Reinforced Bitumen Membranes) are the most common material for flat roofs. Thanks to RBM, leaky roofs that were once expensive and troublesome to maintain are now a thing of the past. Today, flat roofs are low-maintenance and can enjoy a trouble-free life expectancy of up to 35-40 years. When problems do occur with flat roofs, it’s usually due to leakage caused by the failure of the waterproof covering. This may be due to several factors such as bad design, poor detailing, bad installation and inappropriate materials. Other causes can be an inability to withstand movement, thermal shock, impact or other damage, the deterioration of seams, trims or flashings, failure of previous repairs, lack of maintenance or simply the waterproofing material reaching the end of its service life. Damage can also occur as a result of actual foot traffic on the roof caused by non-specialists gaining access. Ponding of rainwater can often occur on flat roofs. Although it is not necessarily a problem in itself, it may be an indication of the degradation of the supporting deck due to water ingress or condensation. It may also indicate the lack of fall to the roof, which may be addressed when refurbishing. Blistering may be present but, and although not problematic, it should be monitored periodically. REFURBISHMENT If re-roofing is required, then a suitable roof covering will need to be decided upon. If it’s just a portion of the roof that requires refurbishing, then it’s likely that the same covering would be chosen to match
Roofing
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Many post-war built schools generally have a number of flat roof areas, as opposed to traditional pitched roofs, and these can be prone to problems if not maintained correctly the original. Whilst there are a medley of options to consider, including slate, clay, concrete tiles and green roofing, a key factor governing this choice will be budget, of course. Refurbishment projects tend to make up 50 per cent of a local authority’s funding under the government’s Building Schools for the Future (BSF) programme – so it’s important that these huge sums of money are spent wisely and effectively. Thanks to the current British Standard Code of practice for slating and tiling, BS 5534, which revised/ republished in 2014, new and refurbished roofs have to be more secure in the face of increasingly extreme weather events. New minimum performance standards for underlay as stipulated by the Standard also mean that new roofs are more energy efficient too. FLAT ROOFING REFURBISHMENT Refurbishment of a flat roof is likely to be reportable to the Local Authority Building Control (LABC) and approval must be sought, unless the contractor is a member of CompetentRoofer. Part L of the Building Regulations may require additional thermal insulation to all re-roofing projects where the building underneath is heated. For example, a school roof installed in 1995 will possibly have about 40mm of rigid polyurethane insulation meeting the then current regulations. In 2012, however, that thickness increased to 140mm. Particular attention needs to be paid to any condensation issues that can occur on cold roofs. Current regulations stipulate that if more than 50 per cent of the existing waterproofing is being stripped, if it’s technically and economically feasible, the whole roof must be brought up to the standard of the current energy related regulations. This means that a roof will require substantially more insulation than is currently present. GOING GREEN Green roofing has become increasingly popular over recent years. Whether it’s transforming a humble outdoor storage building or landscaping main parts of the roof, green roofing offers a planting system that not only looks great and helps soften the look of the school, it’s brimming with environmental, social and economic benefits too. In urban environments, green roofs help attract the birds and butterflies and provide cleaner air, offsetting our carbon footprint and helping combat global warming. They can also help reduce the need for air conditioning
in the summer, and offer a degree of additional insulation in the winter. The lives of waterproofing membranes beneath green roofs are extended, plus sound insulation is improved. Also, water surface run-off can be reduced. In a school, a green roof can provide pupil interest and generate a feeling of well-being amongst both staff and pupils. They can be installed as a complete system and can even be retrofitted to existing roofs. The revised GRO Code is designed to provide assistance for anyone who is involved in the design, specification, installation or maintenance of a green roof. CALLING THE SPECIALISTS Other than simple maintenance issues such as clearing leaves and cleaning gullies, it’s important to call in the specialists from the outset. Trained and competent roofing contractors will not only be skilled in all aspects of roofing, they will be conversant with the latest regulations and knowledgeable about other potential risks, such as from asbestos-containing materials. By appointing a contractor who is a member of the NFRC government-approved CompetentRoofer scheme, schools can enjoy significant cost savings. Through self-certification, these specialists can eliminate costly and time-consuming local authority building control procedures, whilst maintaining performance and legality. Many older schools are listed buildings and require special attention to detail and consideration. Contractors with specialist skills to carry out such repairs or refurbishment work may be found via the NFRC’s National Heritage Roofing Contractors’ Register which is recognised by all UK Heritage Agencies. Roofs help protects schools from all types of weather, but without maintenance, the roof will age until it is no longer able to do its job. If problems are encountered, it’s important to seek the help of a specialist roofing contractor immediately. After all, lining up buckets to catch the rain falling from leaks in the ceiling, or having to teach pupils in temporary classrooms are the last thing that any school wants. !
Dating back over 120 years, the National Federation of Roofing Contractors (NFRC) has led the way in best roofing practice; encouraging first class workmanship, maximum performance, plus the installation of cutting-edge materials. FURTHER INFORMATION www.nfrc.co.uk
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