Most disputes with council planners are about size. ‘Overdevelopment’ is the word they reach for when they think you have tried to fit too much onto your plot: too big, too bulky, not enough garden, too little parking, too many units, or the loss of the gaps that give a street its breathing space. The word doesn’t mean much on its own – the council’s case officer should instead explain exactly what it is they are concerned about.
The standards are guidance, not law
To make an overdevelopment objection stick, councils reach for the numbers in their local plan and design guides: minimum garden sizes, parking ratios, a maximum depth for a rear extension, limits on how much of a plot can be built on. Case officers quote these chapter and verse and treat them as hard rules. They aren’t. They are guidance, written for the average house on the average street, and your house may be nothing like the average.
A guide that limits rear extensions to 3 metres is fine for most terraces. It makes no sense where your neighbour has already extended to 4, or where the house next door sits a good distance away. Falling a little short of a standard, or a little over it, doesn’t in itself mean you are causing any harm – and harm is what a refusal is supposed to be about.
Show there is no real harm
The best answers are specific to your own site. Mrs Ling, in Liverpool, came to us after her council refused a 4-metre rear extension, insisting its guidance capped the depth at 3 metres because anything deeper would overshadow the neighbour. When we looked at the site, there was a 3-metre-high brick wall between the two houses. Nothing was going to overshadow anyone. We submitted the application with a statement that acknowledged the guidance but explained why it simply didn’t apply here, and permission was granted.
That is the pattern that wins. Look at what the houses around you actually have – similar plots, similar gardens, similar parking – and show that your scheme is nothing unusual for the street. Put the garden you are keeping, the parking that works and the gaps to the neighbours on the drawings. An inspector deals in what they can see on the ground, not in words like ‘cramped’.
Use your fallback
Don’t forget what you could build anyway. If you could put up something of a similar size under permitted development, or you are sitting on an unused permission, the council has to weigh that in. The question stops being ‘is this proposal perfect?’ and becomes ‘is it any worse than what you could build without even asking?’ Often the honest answer is no.
When the scheme really is too big
Sometimes the council has a point. Bigger is rarely better. A rear extension a metre deeper than it needs to be adds thousands to the build and often makes the rooms worse, not better. If the officer’s report fairly explains that the scheme is genuinely overloaded, the quicker route may be to trim it back and reapply rather than appeal. A smaller, well-designed proposal usually keeps the planners happy and costs you less to build.
Appealing an overdevelopment refusal
Under the appeal rules introduced in April 2026, the inspector decides on the application papers plus a short written summary, and you can’t add anything later. So the plot sizes and densities up and down your street, the site plan showing the garden and parking you are keeping, the distances to the neighbours – all of it needs to be in the application from the start, and your 250-word summary has to point the inspector straight at why there is no real harm.
If your extension or new home has been refused as overdevelopment, or called cramped or overintensive, send us your refusal for free initial advice. We’ll tell you honestly whether the council’s decision holds up, and if it doesn’t, we’ll prepare and manage your appeal for a fixed fee of £399.