What UK homeowners are actually asking about extensions
These are answers people gave our own quote tool over the last 90 days — 2,501 enquiry journeys, aggregated and anonymised. It is a demand signal from one website, not a national survey, but it is real and it is ours.
Most people are still deciding
Fifty-four per cent describe themselves as planning and researching rather than ready to hire. Ten per cent are ready to hire now. That gap is the whole reason this site leads with rules rather than prices: by the time somebody is comparing quotes they have already made most of the decisions that determine what the job costs.
It also means a lot of the advice aimed at this audience is pitched wrong. Pages that open by asking for a postcode are answering a question most readers haven't reached yet.
What people want built
| Type of extension | Share of enquiries |
|---|---|
| Rear | 51% |
| Side | 22% |
| Wraparound (two sides) | 10% |
| Conservatory | 7% |
| Porch | 3% |
| Loft | 3% |
Single storey outnumbers two storeys three to one — 74% against 24%. And the properties are mostly the ordinary British housing stock: semi-detached 41%, detached 29%, terraced 18%, bungalows 11%. Flats are a rounding error, which fits, because permitted development rights don't extend to them anyway.
The planning permission answer is the interesting one
Asked about the planning status of their job, a third have made no application. Nineteen per cent say permission isn't required and seventeen per cent already have it. But 22% say they don't know whether they need planning permission at all, and another 5% simply answer “I don't know”.
So more than a quarter of people seriously enough into an extension to be requesting builder quotes cannot say whether the thing they're pricing is allowed. That's not a criticism of them — the rules are genuinely fiddly, and “original house” alone catches out people who've read the guidance. It is, though, the clearest single argument for reading the permitted development limits before reading a cost page.
Fifty-eight per cent have no drawings yet, and a further 9% want the contractor to sort the drawings out. Only about a third arrive with plans in hand.
How to read this, and how not to
Two honest caveats. First, this is the mix of people who found one website and used one quote form; it is not a census of British extension activity, and a site that ranked differently would see a different mix. Second, these are self-reported answers given in a form, so “planning permission not required” means the person believes it isn't, which as the numbers above suggest isn't always the same thing.
What it is good for is sizing the gap between what people are told and what they need. The published advice for this audience is overwhelmingly about cost. The data says the first question is permission, the second is drawings, and cost only becomes decisive once those two are settled.
We refresh these figures when the underlying pattern moves rather than on a schedule, and the date this page was last checked is at the foot of it.
Frequently asked
Related reading
If you are in the 27% who aren't sure about permission, start with the permitted development limits. If you are in the 58% without drawings, who draws them and what you need is the short version. And if you want the cost ranges, what an extension costs in 2026 sets them out by type.
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