For anyone planning to extend, refit or alter an existing building in 2006, the energy rules had moved on. On 6 April 2006 a revised Part L of the Building Regulations came into force, together with the Building and Approved Inspectors (Amendment) Regulations 2006. Most of the attention went to new buildings, but the changes for existing ones mattered just as much to owners.
What changed for existing buildings
There were now separate Approved Documents for existing dwellings (L1B) and existing buildings other than dwellings (L2B). In broad terms:
- Extensions must meet set standards for insulation and glazing.
- Replacement windows, boilers and other controlled services must meet minimum efficiency standards.
- Renovation of roofs, walls and floors can trigger a requirement to upgrade insulation where that is practical and pays back over a reasonable period.
- Consequential improvements. Where a building has a total useful floor area over 1,000 square metres, an extension, or the first installation or enlargement of fixed building services such as heating or air conditioning, brings a duty to improve the energy performance of the building as a whole, so far as that is technically, functionally and economically feasible.
Why this matters to your budget
Consequential improvements can add work that the owner did not plan for, such as upgrading lighting, controls or old heating plant elsewhere in the building. Identifying these items at feasibility stage avoids a nasty surprise when the building control application goes in or the tender returns.
Older and listed buildings need particular care. The guidance recognises that some improvements could harm the character of a historic building or cause moisture problems in traditional construction, and allows a sensible balance to be struck. That balance needs to be argued and recorded, not assumed.
Our advice
- Survey the building first, so you know what is there and how it performs.
- Check early whether the floor area threshold and the consequential improvement rules apply.
- Write the energy requirements into the specification, so that every tenderer prices the same thing.
- Agree the approach with building control before work starts.
See our Contract Administration and Building Surveys and Defect Diagnosis services, and our communal heating feasibility study for a mansion block.