Summary of requirements for existing buildings under ADL2B

Consequential improvements apply where the building floor area is over 1000m2 and there is increase in capacity of a fixed building service, or a new extension. The ‘principal works’ (i.e. work on the new or extended parts) must comply with guidance below, and the ‘consequential improvements’ (to the rest of the building) must bring the thermal properties up to stated values, and then also carry out improvements limited by cost effectiveness and a price cap of 10% of the principal works: upgrade services over 15 years old, install metering and low-zero carbon measures. The price cap does not apply to the thermal property improvements. See ADL2B paragraphs 12-16

Extensions. Large extensions over 100m2 and 25% of floor area fall within ADL2A and so must achieve a satisfactory Building Emission Rate. Conservatories have special stated requirements. Other extension works broadly follow the thermal element guidance and services and fittings guidance below. See ADL2B paragraphs 17-26.

Material change of use applies when, for example, the building becomes a public building or ceases to be a dwelling. Works broadly follow the thermal element guidance and services and fittings guidance below. See ADL2B paragraphs 28-31.

Material alteration applies when a service of fitting ceases to comply with the regulation or whose compliance level becomes worse. Works broadly follow the thermal element guidance and services and fittings guidance below. See ADL2B paragraphs 32-33.

Work on a controlled service or fitting, i.e. one to which any of the Regulations Parts G,H,J L or P apply. Windows, rooflights and doors to comply with stated U-values (1.8 for a whole new window or rooflight, 2.2 for a replacement). Controlled services to meet standards below. Commissioning to be notified complete in line with CIBSE Code M and duct leakage testing. See ADL2B paragraphs 34-44.

Guidance on specific building services. Heating and cooling to follow the heating or cooling Compliance Guide. Air handling plant specific fan power to comply with limits (e.g. 2.5 W per l/s for standard HVAC plant) and part load efficiency. Lighting to 45 luminaire-lumens per circuit Watt in general office, industrial and storage areas - other general areas to 50 lamp-lumens per circuit Watt. Effective occupant lighting controls will comply. See ADL2B paragraphs 45-68.

Thermal elements which are new, replaced, renovated or retained. New element U values to meet tabled values (e.g. wall 0.30, flat roof 0.20), and replacement elements (wall 0.35, flat roof 0.25). Renovated elements are to these same values where more than 25% is renovated and within 15 year payback. Retained elements to follow tabled values of threshold and improved U-values (e.g. flat roof 0.35 to 0.25). See ADL2B paragraphs 69-76.

Providing information. Update the existing log book, or provide a new one, as guidance in the CIBSE Building Logbook Toolkit TM31 (see ADL2A paragraphs 81-83). See ADL2B paragraphs 77-80.