The 2006 revisions to the Building Regulations Approved Document L for England & Wales introduced the requirement to notify Building Control of any intended refurbishment work to a thermal element (Roof, Wall or Floor) of a certain size and to present the Building Control Body (BCB) with proposals for the upgrade of its thermal performance, to a required minimum standard.

The 2010 revision of Approved Document L requires a further flat 25% reduction in energy use, over the 2006 regulations for dwellings and an aggregate 25% reduction for buildings other than dwellings, based on a notional building type.
The requirements of the Scottish Building Standards Association (SBSA) Technical Handbook, Section 6 are very similar.

With 99% of the annual built environment consisting of existing buildings, significant carbon emission reductions can only be achieved by upgrading existing building stock (Saving around 150 million tonnes of CO², according to EU figures), the benefit to the building owner/operator will be a reduction in the energy costs associated with heating and cooling.

Can you avoid the extra expense?

Building Regulations Approved Document L (ADL) Part L2B: Conservation of fuel and power (Existing Buildings other than Dwellings) England and Wales requires minimum U-values to be achieved. The regulations state that when refurbishing a flat roof, a check on the insulation within that roof must be made to ensure that it meets the requirements of Approved Document L 2010.

The Exceptions

There are some exemptions, unheated buildings, some listed/heritage buildings or where the payback period (total cost of upgrading versus savings made) exceeds 15 years to achieve. Ultimately the BCB is required to make a judgement on what will be required, Sika Sarnafil therefore advises that Building Control is consulted early in the planning process of the project, as the potential financial consequences for non compliance could be significant.

These requirements are that:

  • A roof that already has insulation installed must achieve a U-value of 0.35 W/m²K
  • A roof with a U- value of less than 0.35 W/m²K must be improved to achieve a U-value of 0.18 W/m²K
  • A new build property / extension roof must achieve a minimum U-value of 0.25 W/m²K
  • A roof repair or overlay that accounts for more than 50% of the individual roof element or 25% of the entire building must comply with the new requirements
  • When an extension is built consequential improvements to the existing building are required and should be not less than 10% of the cost of the extension

Independent Verification

As the market leader in the supply of single ply roofing membranes Sika Sarnafil strives to ensure that it is in step with all relevant regulatory changes and that any advice provided to contractors and clients, regarding the impact of these changes, is accurate and current. However we appreciate that sometimes contradictory advice provided by others may cause confusion. Therefore, listed below are the contact details for some independent bodies that can be consulted on this key topic.

Single Ply Roofing Association (SPRA)
Telephone: 0115 914 4445


National Federation of Roofing Contractors,
Telephone: 0207 436 0387



Local Authority Building Control,
See local telephone directory or call Local Authority