County Inspections
07721 414813
County Inspections, 3 Victoria Avenue, Hadfield, High Peak, SK13 1BJ
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Highly Glazed Extensions
& Conservatories


We have a 100% success rate for demonstrating Building Regulation compliance for highly glazed extensions.

It can be difficult to demonstrate building regulation compliance for highly glazed extensions or for conservatories that are open to the existing dwelling. This is mainly due to the comparatively high u-values for glazing compared to walls as well as the risk of overheating in summer months.

A flexible approach to achieving compliance using SAP is possible by calculating the Co2 emission or DER (dwelling emission rate) for the whole dwelling with the extension or conservatory as proposed and comparing this with a DER calculation for the existing dwelling with a 'nominal' extension of the same size but constructed to current building regulation standards. Assuming the DER of the proposed extension is less than or equal to that of the nominal extension then compliance is achieved.

The main advantage of this approach is that any improvements made to the existing dwelling, such as a new boiler or increased loft insulation can be used to offset deficiencies with the proposed extension.  This method is catered for in the building regulations under Part L1b Section 4.

The assessment process is simple and can usually be carried out without the need of a site visit using the existing drawings prepared by your architect, the specification of both the propsed extension and the existing dwelling. Should the calculations show that compliance is not being achieved we are able to offer advice for improvements to the thermal efficiency of the extension or simple improvements to the existing dwelling.

For a fast and efficient service to assess your highly glazed extension or conservatory using this flexible and cost effective approach, call us on 07721 414813 or send us an email with your query using the Contact Us link on the left.