Can I Build a Granny Annexe in My Garden?

The events of the last year have changed how many older people want to live and whilst they may wish to keep their independence, they want to be close to family as they become more dependent. At the other end of the age spectrum, many young people cannot afford to move away from home when in times past they might have done, but want to have more flexibility around how they live. So-called multi-generational living may not suit everyone if all the generations are living in the same house though! This is where the idea of a ‘granny annexe’ appeals, especially if you have a large garden that has plenty of space.

If you’re thinking a granny annexe might be just what you want, you’ll need to consider a few things carefully, planning regulations being the first and foremost.

Creating a fully self-contained ‘flat’ in your garden, is definitely going to require planning permission – there’s no [legal] way round that. On the upside, it means you can design exactly what you want. Subject to the planning department saying “Yes!”, (and we all know they can say “No!), the annexe becomes a legal part of your home, which can be an advantage if you decide to sell up.

If you’d rather not go down the planning permission route, or if you think there may be challenges (green belt, a conservation area, or if you want to put the annexe in front of the building line of your home), the alternative could be to put a mobile home in your garden under a “certificate of lawful development”.

To clarify, a mobile home is defined as a structure which cannot legally be towed on the road (i.e. it is not a touring caravan), but it still needs to be feasible to transport it on the road legally.

There are size restrictions on mobile homes. This means that it must be a single or twin unit (i.e. two parts joined together down the long axis). A single unit can’t be more than 14ft wide (just over 4m), and the longest practical length of a unit this size is 40ft (about 12m), so it could be transported on a trailer. This is still a perfectly comfortable size for a single person to live in.

A twin unit can’t be more than 22ft 7 (6.8m) wide and 65 ft 7 (20m) long, and must be capable of being separated into no more than two parts for transportation (although if you ever did need to transport this, the logistics may be very challenging!). As this is larger than many family homes these days, this could even be suitable for a family.

These size and shape limits may restrict your annexe but you can of course still have something that is not your average rectangular box – take a look at our ideas here (

Several of our smaller log homes would also make great annexes too – for example the Valo 46A ( or the Emmi 85 (

We’ll work with you to create an annexe that’s exactly suited to your needs. And you can look forward to a sustainable, beautiful, warm and secure annexe in your garden.

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