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So, you may have heard that you can just put an annex in your garden using The Caravan Act, yes?
Well, first take a few minutes to familiarise yourself with what this means and then you can make an educated decision.
Spoiler - it's not that simple...
Our team is often asked about the Caravan act use to allow a garden annex. Because there are so many different interpretations of planning laws by different councils across the country, it is important that:
Often, councils may still cast doubt and insist on some sort of planning application and this is why Blue Bee uses independent, experienced granny annex planning consultants.
Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.
An alternative route to create a granny annexe is to use a structure that meets the legal definition of a “caravan” or mobile home.
Under the Caravan Sites and Control of Development Act 1960 (as amended by the Caravan Sites Act 1968 and later regulations), a “caravan”
is defined as
This definition includes not
only traditional touring caravans, but also larger static caravans or
mobile chalets – even if assembled on site – as long as they satisfy
certain size and construction limits.
Specifically, a twin-unit mobile
home can still count as a caravan if:
There are maximum size dimensions:
in England, a caravan (mobile home) may be up to 20 metres in length, 6.8 metres in width, and with an internal ceiling height up to 3.05 metres.
Anything larger or constructed in more sections would not legally be a
“caravan.” Importantly, a structure fixed permanently to foundations
(like a brick building) is not a caravan – it must be a mobile
unit, typically resting on its own frame or wheels, even if it’s skirted
around the base for appearance.
Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.
Placing a caravan within the curtilage of your house for use ancillary to that house can be done without needing separate planning permission in many cases. The key distinction is between operational development (building work) and use of land.
Planning law generally allows the
use of land within a home’s curtilage for purposes incidental to the
dwelling without treating it as a separate “development,” as long as it
remains part of the same planning unit.
In plain English: if the caravan
is used only as extra accommodation for the people living in the main house (family members, etc.), with no separation in household, then “there would be no development taking place” in the eyes of the law – no material change of land use – and thus no planning permission required.
Provided the caravan is within the residential curtilage and used for ancillary residential purposes
(not as an independent dwelling), “planning permission is not required”
because it doesn’t create a new planning unit. The use is considered
part of the normal use of the dwellinghouse.
Keep reading, though... it's not that simple...
However, this scenario rests on the caravan meeting the legal definition and the use remaining ancillary.
If those conditions aren’t met, the council can argue a material change
of use has occurred (for example, turning your garden into a separate
dwelling site). Although a well-known appeal case established that using a mobile
home as ancillary accommodation for relatives did not require
planning permission since it did not amount to a separate planning unit
(the family still functioned as one household), as noted below, you still need to check with your local council, and get proper confirmation in writing to cover yourself. But if you were to rent
the caravan to a stranger or use it as an entirely independent
residence, that would not be ancillary and would definitely need permission.
Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.
Councils can be wary of caravan annexes because if the unit has all the facilities (kitchen, bathroom, etc.), it looks like a separate dwelling. The test is how it’s used in practice.
In fact, it’s possible
for a fully self-contained mobile unit to be ancillary if occupied by
dependent relatives as part of one household. The presence of a second
front door or kitchen does not automatically create a new planning unit –
it’s about the relationship and intention.
This is a grey area and
often comes down to “fact and degree” on a case-by-case basis.
Many annexe suppliers build units to
caravan specifications and advise using the Caravan Act route.
The
typical process is: ensure your design falls within caravan size limits;
site it within the curtilage (usually as close to the main house as
reasonable); and use it for a family member.
However, it’s highly advisable to
then apply for a Certificate of Lawfulness (LDC) for use of the
land for an ancillary mobile home, to get the council’s formal sign-off
that no permission is needed.
If the LDC is granted, you have permission
in principle to station the caravan indefinitely as ancillary
accommodation. If the council refuses the LDC (disagreeing on the facts
or use), you might fall back to needing full planning permission after
all.
Important: You are responsible for making sure that
you follow all rules pertaining to your own property and the area you
are in and that you obtain the relevant permissions.
Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.
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Please ask and we can put you in touch with a independent specialist garden annexe planning consultant.
The "Caravan Act" refers to the Caravan Sites and Control of Development Act 1960, as amended by the Caravan Sites Act 1968. It defines a "caravan" as any structure designed or adapted for human habitation that's capable of being moved from one place to another, whether towed or transported on a vehicle. Because a caravan is legally a movable chattel rather than a building, some annexe suppliers use this definition as a route to avoid the usual planning permission process. Whether a specific structure and its intended use actually qualify is a legal judgement, not a given - you must check with your local council or a planning consultant before assuming the exemption applies to you.
In England, a structure only counts as a caravan if it's no more than 20 metres long, 6.8 metres wide, with an internal ceiling height of up to 3.05 metres. A twin-unit mobile home can still qualify if it's made of no more than two sections assembled on site and is physically capable of being moved as a single unit by road once assembled. These limits are a starting point, not a guarantee - always confirm your specific unit's specification meets the legal definition with the manufacturer and your council before ordering or installing anything.
The main difference is that Permitted Development allows certain buildings to be constructed without applying for planning permission, whereas the Caravan Act defines what legally qualifies as a caravan or mobile home, which may be placed in a garden without planning permission under certain circumstances.
Permitted Development generally applies to permanent garden buildings, such as offices, gyms and summerhouses. These must meet specific planning restrictions covering their size, height, location and intended use. Importantly, the usual Permitted Development rights for garden outbuildings do not allow them to be used as separate, self-contained living accommodation.
The Caravan Act, on the other hand, provides a legal definition for mobile structures, including certain granny annexes. If a structure qualifies as a caravan and is placed within the residential curtilage of a house for genuinely ancillary use, planning permission may not be required. Unlike conventional garden buildings, caravan annexes can potentially provide sleeping, cooking and bathroom facilities, provided their use remains ancillary to the main house rather than creating an independent dwelling.
Neither route automatically allows you to create a separate residential property in your garden.
The important distinction is that Permitted Development grants planning permission for specified development, while the caravan approach may involve no development requiring planning permission in the first place.
Our advice: Before purchasing or installing a granny annexe, check which planning rules apply to your proposed structure and intended use. We recommend obtaining confirmation from your local planning authority, ideally through a Certificate of Lawfulness, rather than assuming either route automatically applies.
Sometimes, yes - placing a caravan within the curtilage of your house for use ancillary to that house can avoid needing planning permission, since you're not building a structure, just changing how part of the land is used. But this only holds if the structure meets the legal caravan definition and the use stays genuinely ancillary - get either wrong and you could be in breach without realising. Don't proceed on assumption alone: get written confirmation from your local council before installing anything.
Potentially, provided it remains ancillary accommodation tied to the main house rather than an independent dwelling. Councils look at whether you're still functioning as one household - sharing meals, bills, and day-to-day life - or effectively living separately. This is assessed on the specific facts of your situation, so it's not something to assume in advance. Speak to your local council before treating this as settled.
Often, yes - a well-known appeal case confirmed that using a mobile home as ancillary accommodation for relatives didn't require planning permission, because the family still functioned as one household. But that case turned on its own specific facts, and councils vary in how they interpret ancillary use. You must check your own circumstances with your local council, or apply for a Certificate of Lawful Development, before relying on this as a route.
No - a caravan isn't a building, so it's assessed under a different legal test entirely (the 1960/1968 Act's caravan definition and ancillary-use rules), not under Permitted Development. Don't assume that because PD rules don't apply, no rules apply - the caravan route has its own strict conditions, and you should confirm with your council which route, if any, genuinely covers your plans before proceeding.
Not necessarily, if the structure meets the legal definition of a caravan and its use remains genuinely ancillary to the main house. But this rests on interpretation of the facts, not a fixed rule, and getting it wrong can mean enforcement action later. You must apply for a Certificate of Lawful Development (LDC) or get written confirmation from your council before going ahead - don't rely on this FAQ, or general guidance like it, as a substitute for that check.
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