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Building Regulations and Glazed Extensions

Annabel Fenwick | 2nd December 2015

If you are increasing the floor print by over 25% you have to comply to Part 1LB of building regulations. To overcome the constraints of this, one can prove - through a SAP Assessment - that upgrades to your existing home such as installation of new boiler, loft insulation and double glazed windows will improve the OVERALL thermal efficiency and carbon emissions of the building.

Building regulation documents

Our roof lanterns are specified with double glazing as standard which can be further enhanced with the introduction of solar glass or even triple glazing. The glazing units themselves have a u-value of 1.2 which is categorised as high performance. But what is a u-value? In essence it measures the thermal transmittance of a material, how effective it is as an insulator (or not as the case may be). So the lower the u-value, the better its thermal performance and similarly the higher the u-value, the greater the heat loss.

The thermal performance together with carbon usage is critical when looking at the overall environmental performance of a building. This is why u-value calculations will invariably be required when establishing an appropriate design for a new extension and more specifically the introduction of a roof lantern into a new or existing building.