Extensions · Fabric trade-offs

Area-weighted U-value calculations

A project-specific assessment where glazing and element performance need to be considered together.

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Completed extension combining insulated solid walls, full-height glazing, a glazed door and rooflights

Overview

For some extensions and alterations, an area-weighted calculation can demonstrate that the proposed fabric arrangement performs no worse than the applicable reference approach. It can be useful where the design includes more glazing, but it is not an automatic workaround and suitability depends on the project and regulatory route.

Good to know

Project requirements vary by building type, location and timing. Send us the project information and we will confirm the right assessment route before providing a quotation.

Particularly useful for

  • Domestic extensions with significant glazing
  • Projects comparing improved fabric specifications
  • Designs where a simple elemental check is insufficient
  • Building Regulations submissions needing a clear evidence trail

Our approach

  1. 01

    Confirm that the method is appropriate for the particular work

  2. 02

    Measure relevant element and opening areas from the drawings

  3. 03

    Compare the proposed and reference heat-loss performance

  4. 04

    Advise on the most effective specification changes and issue the calculation

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Send us the project

Upload the drawings and a few project details. We will review what is needed and confirm the scope before work begins.

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