The garden room is the boom structure of the era — the office, the gym, the studio at the end of the lawn — and its planning analysis has two halves of very different difficulty: the dimensions, checkable in an afternoon, and the use — the modern battleground no size compliance answers.
The Checkable Half: Size, Height, Siting
Garden structures enjoy genuine exemption territory within the wrap: area limits counted cumulatively across all such structures on the property — the new room plus the existing shed plus the greenhouse, aggregated, which is how compliant-looking projects go over threshold; height limits differing by roof type — flat and pitched treated differently; the remaining garden — private open space that must survive the works; and siting conditions relative to the house and boundaries. All of it is checkable at drawing stage against the actual conditions — the suppliers’ “no planning needed” banner being marketing about the typical case, not advice about your garden’s history — and the general disciplines apply: the cumulative measure first, the Section 5 declaration where any edge exists, per the full exemption guide. Boundary siting earns one extra thought: the structure hard against the fence is the structure most likely to be complained of, whatever its compliance — the neighbour dimension is design input, not just legal risk.
The Battleground Half: Use, and the Drift
The exemption’s world is ancillary domestic use — purposes incidental to the enjoyment of the house — and use is where compliant structures drift into trouble: the business with callers — the home office where you quietly work is one thing; the treatment room, studio or workshop receiving clients, deliveries and traffic raises material-change-of-use questions the structure’s dimensions never answer, and generates exactly the neighbour complaints that start warning letters; the sleeping structure — the garden room drifting into guest accommodation, the teenager’s bedroom, or the short-term let raises use questions planning-side and building-regulations exposure besides, with the letting variant walking directly into the short-term-let framework; and the drift itself — none of these arrives as a decision; each arrives as a gradual settling that nobody chose and the file can’t defend. The discipline: name the intended use honestly at the start — where it has any commercial or residential edge, take the advice before the concrete, because the permission conversation is cheap at drawing stage and the enforcement conversation never is. And on sale, the structure’s paperwork joins the folio’s story like every other work, per the conveyancing guide.
The two-question test before ordering the unit: measured cumulatively against everything already in the garden, does the wrap still fit — and stated honestly, is the use ancillary to living in the house? Two clean yeses: proceed with the file kept. Anything else: the advice first.
A garden room planned — or one whose use has drifted? Both halves checked, plainly: 01 5827148.