Can I Build a Granny Annexe in My Garden?

The COVID-19 pandemic has left many of us, especially older people, thinking differently about how we want to live our lives. Our older relatives still want to keep their independence, but some now also want to be closer to family in case they become less self-sufficient. 

At the other end of the age spectrum, many young people cannot afford to move away from home, but want to have more flexibility around how they live. 

Multi-generational living may not suit everyone if all the generations are living in the same house though! This is where a ‘granny annexe’ comes in (or grandad!), especially if you have a large garden that has plenty of space.

If a granny annexe might be the solution to your problem, maybe it’s time to look at what you can realistically fit into your space, and then consider planning regulations.

Creating a fully self-contained ‘flat’ in your garden will require planning permission – there’s no [legal] way round that. On the upside, it also means you can design exactly what you want. Once the planning department say “Yes!”, (though admittedly they can say “No!), the annexe becomes a legal part of your home, an advantage if you decide to sell up.

There is an alternative to seeking full planning permission, for example if you live in a conservation area, or you want to put the annexe in front of the building line of your home. You could investigate installing a mobile home in your garden under a “certificate of lawful development”. This basically says that the council agrees that you don’t need planning permission – contact your local council to find out more.

So what is a mobile home? It’s 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 technically feasible to transport it on the road legally. 

Thus, 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 no more than 40ft long (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 has to be able to split into no more than two parts for transportation (although in reality, it would require a feat of logistics to move it). That’s bigger than many new build homes these days, so it 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. 

If you’re happy to go down the full planning permission route, then several of our smaller log homes would also make great annexes too – for example the Valo 46 or the Emmi.

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. Get in touch to discuss your ideas with us.