Extension Architecture

  It gets refused, or sent back for redesign, and both outcomes cost weeks or months Chartered Surrey architects see this happen more in Cobham than almost anywhere else, because the borough's generous plots make it easy to design something bigger than Green Belt policy actually allows. What Counts as "Too Big" in Green Belt Policy Terms? National planning policy measures this against the original house, not against the plot. Roughly a 50% increase in the building's volume is the commonly applied threshold before an addition counts as disproportionate. Cross it, and the application faces a much steeper approval challenge, no matter how well designed the extension is. Why Does This Happen So Often in Cobham Specifically? Because there's usually nothing physically stopping an oversized design from being drawn up. Large plots and generous Neo-Classical or Ultra-Modern homes make ambitious extensions genuinely tempting, and there's often real space for them. The ...

  Drive from Between Streets out towards the Fairmile and the houses change completely within about a mile. Modest interwar semis give way to gated detached plots sitting behind hedges, and the planning position shifts just as sharply. Any Cobham architecture practice working here starts with the plot rather than the drawings, because two owners can be neighbours in postcode terms and still be governed by entirely different rules.  Most guides to extending in Cobham talk about the town as one place. It isn't. So here's a more useful map of it. Why KT11 Property Types Decide Your Options Before Policy Does Start with the building rather than the rules. Cobham's stock splits roughly three ways, and each responds differently. Detached houses on generous plots , concentrated around the Fairmile, Oakdene Road and the roads running towards Oxshott. Physical space is rarely the constraint here. Policy usually is, because these are the plots most likely to sit in Green Belt. Olde...

  Cobham sits within Elmbridge, one of Surrey's most Green Belt heavy boroughs, and that single fact shapes almost every extension project here. Do I need planning permission for a Cobham extension? It depends entirely on whether the property sits on Green Belt or protected land, which covers a large share of Cobham. Where Green Belt status applies, full planning permission is almost always required, even for a fairly modest extension, since national policy treats disproportionate additions to Green Belt properties as a specific planning test. Outside Green Belt boundaries, many Cobham homes retain standard permitted development rights, allowing extensions up to 3 metres for terraced and semi-detached properties, or 4 metres for detached homes, without a full application. Checking which category a specific property falls into is the first step cobham architects take before any design conversation begins.  What counts as a disproportionate addition on a Green Belt plot? Natio...