Businesses specialising in home extensions and renovations alter, enlarge or update existing houses and flats. Extension work may include single- or double-storey additions, rear or side extensions, loft conversions, conservatories and garage conversions. Renovation projects can range from updating one room to refurbishing an entire property, including changes to layouts, finishes, fittings and building services. Customers may use these businesses for design coordination, preparation of plans, structural work, bricklaying, roofing, glazing, insulation, plastering, plumbing, electrical work, joinery, flooring and decorating. Some contractors manage a project from initial survey through to completion, while others carry out particular trades or stages. Work may require planning permission, building regulations approval or agreement under the Party Wall etc. Act, depending on the property and the proposed changes.