Building Regulations


Home energy efficiency and the Buildings Regulations

Britain has a long history of controls on building construction. As far back as the early 1200s, there were problems of uncontrolled building in London, especially around party walls, gutters, the siting of ablutions and fire risk. Local ordinances were developed to tackle the problems at a community level.

The Great Fire of London, exacerbated by the congested layout of buildings and combustible building materials, led to the introduction of the London Building Act 1667, covering the main City. This provided for the employment of enforcement surveyors. A comprehensive Act was introduced in 1774 to cover the whole of London’s built-up area, and local building control regulations had been introduced in many British cities by the end of the 18th century.

The widespread cholera epidemic of the 1830s shone a light on the public health implications of uncontrolled building, and for the first time is was recognised as a national problem requiring national legislation. Developers and local authorities resisted this and local control was maintained through the Local Government Act 1858. This empowered local authorities to make byelaws to control the construction of buildings.

The Public Health Act 1875 consolidated a raft of Victorian public heath legislation, and subsequent Acts of 1890, 1907 and 1936 gave local authorities even greater control over building, still with a focus on public health implications.

By 1936, 60 local authorities were still to develop building byelaws, raising the need for a national system again. The Second World War interrupted progress, and afterwards any form of intervention was seen as restricting the urgent need for reconstruction. The replacement of local byelaws by national legislation did not happen until the introduction of The Public Health Act 1961 and the Health and Safety etc Act 1974.

The first set of national building standards to prescribe specifications for local regulations was introduced in the Building Regulations 1965. A nationwide Building Act was finally introduced in 1984, 144 years after it had first been proposed. Section 1 of the Act gave powers to the Secretary of State to make Building Regulations ‘for the purposes of ‘…furthering the conservation of fuel and power’.

The inclusion of energy efficiency considerations in Building Regulations can be traced back to 1962, when provisions were added to control condensation, with indirect implications for energy use. In 1972 this was extended to include home energy conservation measures. Subsequent iterations in 1976, 1985, 1990, 1995, 2002, 2006 and 2013 tightened up standards for home energy efficiency.

The main thrust of energy efficiency measures were set out in Part L of the 1984 Act, which gave guidance on building fabric. It was updated in 1995 with a wider focus on energy efficiency. Part L went through fundamental changes in 2006, introducing the Standard Assessment Procedure (SAP) for the assessment of the energy and environmental performance of dwellings, including, for the first time, consideration of carbon emissions.

Part L of the current Building Regulations 2010, Conservation of fuel and power, is now supported by four guidance documents and two compliance guides.

Most of the recent changes to the Building Regulations focus on the U-value of homes. This is a measure of the effectiveness of insulation. Over time, the requirements for walls have been tightened significantly:

  • 1965; 1.70
  • 1976; 1.00 (1.70 for semi-exposed walls)
  • 1985; 0.60 (1.00 for semi-exposed walls) – cavity wall insulation being installed as standard
  • 1990; 0.45 (0.60 for semi-exposed walls) – thicker wall cavities adopted
  • 2002; 0.35
  • Current; 0.30

There have also been radical improvements in roof space insulation as a result of the following U-value requirements:

  • 1965; 1.40 (achievable with less than 3cm of insulation)
  • 1973; 0.60 (approximately 7cm of insulation)
  • 1985; 0.35
  • 1990; 0.25
  • 2002; 0.20
  • Current; 0.17 (approximately 25cm of insulation)

Building regulations make up an important part of your EPC calculations.  Book an EPC today to find out how energy efficient your home is.

Loft Insulation

Loft Insulation

Roof insulation

Modern houses are built with loft insulation, but older properties may be losing a quarter of their heat through the roof. Installing or topping-up insulation in a standard loft is an easy and cost-effective way of making a home more energy-efficient. 

Types of loft insulation

For an accessible loft, the most straightforward method is to lay loft rolls of mineral, glass or sheep’s wool between and over the ceiling joists to a depth of 270mm. A layer is placed between the joists then another is laid at right angles to cover them.  For topping up, the appropriate depth of loft roll is simply laid on top of the existing material.  The loft door can be insulated, but it is better to replace it with an insulated trap door.

The second method, blown installation of fire-retardant mineral wool or cellulose, is for roof spaces with difficult access. The process usually takes no more than a couple of hours.

Finally, for flat roofs, expanded polystyrene insulation boards can be attached on or beneath the roof. These can be a bit more expensive and complicated to install, and can lead to condensation problems, so installation is best left to a professional.


If the loft is used for storage and there is insufficient joist depth to accommodate the insulation, there are two solutions. The first is to infill between the joists with loft roll and then lay insulation boards and chipboard loft boards across the top. Alternatively, the level of the loft floor can be raised to accommodate two layers of loft roll, by fitting battens across the joists and nailing chipboard loft boards on top.

For either method, a gap should be left between the loft insulation and the boards to prevent condensation and compression of the loft roll, which will reduce its efficiency.

Loft conversions

The floor of an existing loft conversion can be insulated to keep the rest of the home warm, with loft roll added between pitched roof rafters and insulation boards to false ceilings, walls and dormers to keep the loft room itself cosy. A 50mm gap is needed between insulation boards and roofing felt for ventilation.

Other things to remember

For DIY, choose products with an ‘Energy Savings Trust Recommended’ logo, insulate pipes and tanks and do not install loft roll beneath the cold water tank. Remember to wear protective clothing and a mask.

If the space is used to store perishables like photographs or clothes, the roof should also be insulated to keep more heat in the loft.

An insulated loft needs to be adequately ventilated around the eaves to prevent damp. If there is an existing damp problem it is best to get professional advice.

Costs and savings

270mm of new loft insulation could yield annual savings of £225 for a detached house or £135 for a three bedroomed semi-detached. The cost would be £395 or £300 respectively. It may be possible to get grants through the Energy Company Obligation (ECO) towards the costs. Check with your energy supplier.