Built by builders, run on official data

Siteline exists because of a conversation we kept having on site visits. A homeowner has an idea — a kitchen across the back, a bedroom in the roof — and the first three questions are always the same: can I build it, what will it cost, and is it worth it? Answering them properly used to take a consultant's afternoon. The data to answer them has been public for years; it was just scattered across a dozen government systems that don't talk to each other.

So we connected them. Siteline resolves an address, checks it against official planning constraint boundaries, pulls the real sold prices around it, and puts honest cost ranges next to the result — every figure cited, every limit stated. It is the pre-feasibility check we wished our own clients could run before the first meeting.

Who's behind it

Siteline is built and operated by the Hampstead Renovations Group — a design-and-build firm working across North London. That parentage matters in both directions: the cost ranges on this site are calibrated from our real project ledger rather than national averages, and the field notes on the borough pages come from applications we've actually taken through these planning departments.

It also means we're straightforward about the commercial model: Siteline is free to use, and if you ask for a feasibility review, that consented request is routed to Hampstead Renovations or a vetted RICS/RIBA partner. We do not sell your data, and the methodology page documents exactly what every number is built on.

What Siteline is not

We are not planning consultants and this is not advice — it is intelligence for the moment before you spend money on advice. Planning outcomes belong to local authorities; estimates here are ranges to be verified by qualified professionals. The site will tell you when confidence is low rather than dressing it up. That honesty is the product.