Replacement Dwelling Forty Percent Larger Than the Original Approved by Basildon in the Green Belt

In 2023, Basildon Borough Council approved planning permission for a replacement dwelling in the Metropolitan Green Belt near Billericay that is 40% larger than the building it replaces — a significant result given the NPPF's requirement that a replacement must not be materially larger.

I argued successfully that the increase was justified by reference to a fallback of previously approved extensions, and that the repositioned dwelling would create a greater sense of openness than the existing arrangement.

Green Belt Replacement Dwelling in Basildon

I secured planning permission from Basildon Borough Council for a replacement dwelling in the Metropolitan Green Belt near Billericay.

The new dwelling is 40% larger by floor area than the one it is replacing — a significant increase that required careful justification under Green Belt policy.

The NPPF allows the replacement of a dwelling in the Green Belt as an exception to the general prohibition on new buildings, provided the new building is in the same use and not materially larger than the one it replaces.

Demonstrating that a 40% increase was not 'materially larger' required a multi-strand argument.

First, I established that the proposed replacement dwelling would be the same size as the existing dwelling together with the various approved extensions it had been granted permission for over the years. Those prior extension permissions created a fallback position — the Council had already accepted a certain amount of additional floor area at this site. A replacement dwelling of the same size as the extended dwelling was therefore an appropriate benchmark.

Second, I demonstrated that the replacement dwelling would be repositioned more centrally within the plot. This repositioning, combined with the removal of various outbuildings and structures, would result in a perceived greater sense of spaciousness and openness across the site as a whole — reducing the overall visual impact even though the principal building was larger.

The Council agreed and granted permission for the new dwelling.

Planning Application Advice

If you are seeking to replace a dwelling in the Green Belt and want to maximise the permitted size, a careful analysis of previous permissions and the openness impact can make a significant difference. Contact me to discuss your project.

Andrew Ransome MRTPI - Email: andrew@andrewransome.co.uk

About me

Andrew Ransome is a Planning Director and a Chartered Member of the Royal Town Planning Institute (RTPI), with more than two decades of experience in town planning.

He specialises in delivering strategic planning solutions for complex developments across both rural and urban environments, helping clients navigate planning challenges and unlock development opportunities. Connect with Andrew on Linkedin.

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Get in touch for planning advice: Email: andrew@andrewransome.co.uk

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