C O N T E X T 9 0 : J U LY 2 0 0 5 19 CHRIS WOOD Part L: a question of compromise The impact of the changes to Part L (Conservation of Fuel and Energy) of the building regulations, due to come into force at the end of the year, will depend on clear guidance. All building work to existing buildings, including repairs, will need building regulations approval when the dramatic changes to Part L (Conservation of Fuel and Energy) come into force. Where an extension or change of use is permitted, there will be a requirement to carry out additional improvements to energy conservation elsewhere in the building. English Heritage is revising its guidance¹ on how the objectives of energy conservation and building conservation can be met without harming the character of traditional buildings. A recent survey amongst conservation officers highlighted the importance of including case studies in the revision: those who have examples of good and bad applications of Part L should please contact the author ([email protected]). The desire to tighten the energy performance standards for buildings are part of the government’s response to reducing greenhouse gas emissions which cause global warming. Buildings account for nearly half of the carbon dioxide generated. The main change is that more work in existing buildings will now be subject to the building regulations. Four new approved documents (ADs) are proposed. ADL1B (dwellings) and ADL2B (non-dwellings) will cover existing buildings with separate documents for new build. These new ADs define the type of work that is now subject to building control, and set out the standards that are considered reasonable. These documents do not go into technical detail: this is to be provided through a second tier of approved technical references prepared by industry and the professions. English Heritage’s interim guidance note (IGN) would come under the category of a ‘second tier’ document. The ODPM recognises that it is often not practical or cost effective to achieve the standard of energy efficiency in existing buildings that is appropriate for new build. Equally, the ODPM does not want to discourage people from improving properties because the cost of achieving the standards is too high for the average homeowner to contemplate. Its approach concentrates on achieving worthwhile improvements at reasonable marginal cost. A suitably qualified person will be required to produce a report (referred to as an energy statement) summarising what energy efficiency measures are to be included, the expected benefit and the estimated marginal costs. The most important proposal relates to the requirement to improve the whole building once work of a sufficient scale is scheduled. Previously only those elements of the building that were being altered or replaced were subject to control. For example, if a house is being extended, as well as the extension itself being required to meet energy performance standards, the regulations could call for extra loft insulation to be added, cavity walls to be filled or a new efficient boiler to be installed as a condition of the building regulations approval. These ‘consequential improvements’ would also be required when a change of use was permitted. Unless the owner wished to go further, the additional work should only include measures that achieve a payback in less than seven years. A marginal cost cap of 10 per cent limits the number of such measures that must be included. These costs could include commissioning the energy statement. In most cases this would rule out double glazing as a viable option. The current proposals introduce the concept of ‘controlled elements’, and their ‘alteration or renovation’ as well. This means that when any part of the building envelope such as roofs, floors or walls is subject to substantial repair or replacement, building regulations approval will be required to the standards proposed in Part L. At present, consequential improvements are not being proposed where the building works are confined to repairs.
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