Extensions and replacement dwellings

• Posted by David Jones on 16th Dec ’09 at 16:22 UTC
• 0 comments

General Permitted Development Order (GPDO) Interpretation.

In December 2008 I published a Blog commenting upon the amendments to the General Permitted Development Amendment Order 2008 December 2008 Blog.

At that time I anticipated that contrary to the Government′s aims and objectives, the revised order would in practice increase the workload for local authorities due to the lack of precision in defining certain aspects of the order.

Twelve months on and a review of local authority records reveals a significant increase in applications for certificates of lawful proposed development together with numerous informal enquires seeking guidance.

Virtually every week the DC forum section of Planning Magazine contains queries from planning professionals and local authorities seeking clarification upon the interpretation of the amended order.

In my blog of December 2008, I suggested that the new order could be advantageous for those seeking to obtain consent for large replacement dwellings. Most adopted Local Plans contain polices which seek to restrict the size of replacement dwellings in open countryside locations. Polices often seek to limit the volume of the new dwelling to that of the original dwelling plus a specific percentage or specific cubic capacity increase or use more general language such as the new dwelling shall not be disproportionate in size to the dwelling being replaced.

The majority of Local Plan polices pre-date the GPDO amendment which came into force on the 1st October 2008. The original 1995 order limited extensions to either 10% or 15% increase in cubic content (compared to the cubic content of the original dwelling). The 1995 GPDO thus sat comfortably with most local plan polices which sought to limit the size of extensions and replacement dwellings in open countryside locations.

The revised order (in certain circumstances) allows significant extensions to existing dwellings. In some cases the original dwelling can be doubled or tripled in size without planning permission.

Evans Jones LLP are now seeing appeal decisions in which inspectors have treated potential GPDO extensions as the “fallback” position when determining appeals against the refusal of consent for replacement dwellings.


One of the anomalies within the order concerns extensions which project beyond the principal elevation and do not front a highway. When determining applications for replacement dwellings it is appropriate for a local authority to consider to what extent the property could be extended taking advantage of the provisions contained within the GPDO.

This establishes the fallback position from which one can then determine what impact the replacement dwelling has upon the landscape compared to the existing dwelling (as might be extended under the GPDO).

Appeal Inspectors have accepted this argument (where there is a realistic prospect that the applicant could extend the existing dwelling). Appeal Decision.

Subject to the replacement dwelling having a null or positive impact (when compared to the fallback position), appeal inspectors have been allowing appeals. Evans Jones have reviewed numerous appeal decisions relating to these issues and submitted representations to local authorities to support replacement dwelling schemes.

For more information please contact David Jones DDI 01242 531411 or Sara Bagshaw DDI 01242 531412

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