SAP (Standard Assessment Procedure) is the UK Government's approved methodology for assessing the energy and carbon performance of residential properties. It is mandatory for all new dwellings, including those created through conversions, such as:

• Barn conversions

• Office-to-residential conversions

• Sub-division of a single dwelling into multiple flats

• Merging of multiple units into one dwelling

• Change of use from non-residential to residential

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When SAP Is Required for Conversions

SAP calculations are typically required when:

• A new dwelling is being created, regardless of the building’s previous use.

• The conversion involves a material change of use, as defined in regulation 5 of the Building Regulations.

• A new EPC is required (mandatory upon sale, rent, or completion of the works).

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These projects fall under Part L1A or L1B of the Building Regulations, depending on the extent and nature of the work.

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