Getting the Tonbridge annexe classification right from the start, mobile home, incidental outbuilding, or genuine dwelling, shapes the entire project timeline and cost. We establish this honestly before any design work begins.
Get Your Free Route CheckThe planning position for a Tonbridge annexe comes down to two questions, is it genuinely mobile within the Caravan Act’s size limits, and is it genuinely ancillary to the house rather than a separate, independent dwelling.
A structure meeting the caravan definition, movable by road, built in no more than two sections, within 20 metres by 6.8 metres by 3.05 metres internal height, can often be sited in a Tonbridge garden without full planning permission, provided it stays ancillary.
Where a Tonbridge annexe is permanently fixed, or genuinely self-contained with its own facilities used independently, the caravan and permitted development routes generally don’t apply, and a full application becomes the realistic path. A Tonbridge annexe needing full planning permission usually needs both, our Building Regulations drawings in Tonbridge service covers the technical compliance side, and our structural calculations in Tonbridge service covers the engineering detail.
Caravan Act, permitted development, or full planning
Movable structures that may need no permission at all
Permitted development limits checked properly
Applications built to be approved

Every Tonbridge annexe enquiry starts with establishing the real facts, is the structure genuinely mobile within Caravan Act limits, is it staying incidental to the house, or is it a self-contained dwelling, since that shapes the whole route.
From there, we prepare exactly what your Tonbridge project needs, whether that’s a Lawful Development Certificate confirming caravan or permitted development status, or a full planning application.
Structural and building regulations input runs alongside the planning process for Tonbridge annexe projects, whichever route applies.
Honesty about what your Tonbridge annexe actually needs comes before any recommendation, not after we’ve quoted for the more expensive route.
We understand the genuine legal distinction between incidental and self-contained use for Tonbridge annexe projects, which is exactly what most generic guidance gets wrong.
A Lawful Development Certificate, where your Tonbridge annexe genuinely qualifies for it, gives you written confirmation rather than a risky assumption. If you need help with a granny annexe, give us a call on 0330 133 5316 or fill in the form below.
Not automatically, a mobile structure meeting the Caravan Act’s size and mobility test, or a genuinely incidental outbuilding, can potentially avoid it in Tonbridge, but a self-contained annexe with its own facilities used independently usually can’t.
Yes, potentially, if your Tonbridge annexe meets the legal size limits, 20 metres by 6.8 metres by 3.05 metres internal height, and is genuinely capable of being moved by road, it may qualify as a caravan under the 1968 Act.
Class E permitted development in Tonbridge covers incidental structures like a home office or gym, subject to height and coverage limits, but not genuine independent living accommodation with its own bedroom, bathroom, and kitchen.
Once a Tonbridge structure functions as independent living space, its own facilities, used separately from the household, it’s no longer incidental, and neither permitted development nor the Caravan Act route typically applies.
Yes, this is genuinely worth having for Tonbridge projects, confirming the position in writing protects you if the classification is ever questioned, especially at the point of sale.
Absolutely, Tonbridge annexe clients get the planning classification and building regulations detail handled together, not as separate, disconnected pieces of work.