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SAP Calculations for Conversions.  

L1B – SAP calculations for conversions

If you alter a building such that there is a material change of use, then we can provide SAP calculations to demonstrate compliance with Approved Document L1B.

A material change of use is defined to be where, after the change:

  • the building is used as a dwelling, where previously it was not;

  • the building contains a flat, where previously it did not; or

  • the building, which contains at least one dwelling, contains a greater or lesser number of dwellings than it did previously.

Compliance is achievable provided the calculated CO2 emission rate for all the dwellings within the proposed building is no greater than if each dwelling had been built to the minimum standards of Approved Document L1B.

The CO2 emission rate for each dwelling is calculated using SAP, the Government’s approved methodology for calculating the energy performance of dwellings.

Our experienced assessors can guide you smoothly through the process, offering the greatest level of design flexibility along the way.

In a Nutshell

We will assess the dwellings based on the design-specification provided. The vast majority of projects we assess achieve a pass first time. If a pass is not achieved we will recommend cost effective options to achieve a pass. For example, improvements to the heating system, increase in insulation or a higher standard of glazing.

Once a satisfactory specification has been agreed we shall issue a copy of the SAP report for submission to Building Control.

Upon completion of the construction works we will update the SAP calculations to incorporate any changes to the design and issue a copy of the Energy Performance Certificate.


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