Consequential Improvements

What is it?

Regulation 28 of the Building Regulations, Section 6 Consequential improvements of Approved Document L2B require additional work to make an existing building more energy efficient when certain types of building work are proposed.

These requirements arises in existing buildings with total useful area of over 1,000 m2 when the proposed work consists of or includes:

  • a) An extension
  • b) The initial provision of any fixed building service (other than a renewable energy generator)
  • c) An increase to the installed capacity of any fixed building service (other than a renewable energy generator)

What is it for?


The assessment is used to demonstrate compliance against approved document Part L2B of Building Regulations.


When consequential improvements apply, in addition with the proposed building work (the principal work), should be made to ensure that the building complies with Part L, to the extent that such improvements are technically, functionally and economically feasible. The principal works must comply with the energy efficiency requirements in the normal way.

Where a building is extended, or the habitable area is increased, a way of complying with regulation 28 would be to adopt measures such as those in Table 01 to the extent than their value is not less than 10% of the value of the PRINCIPAL WORKS. The value of PRINCIPAL WORKS and the value of the CONSEQUENTIAL IMPROVEMENTS should be established using prices at the date of the proposals are made known to Building Control Body.

Finished Projects




Goring by Sea