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All About the Granny Annexe

  • 2 years ago

A granny annexe is a great solution for an elderly loved one who needs a bit of extra help but isn’t ready for a care home just yet. More and more UK residents are looking to build granny annexes and it’s thought that multi-generational households will increase by almost 200% by 2050 due to the rising costs of elder care.

Some local planning authorities aren’t quite so keen on annexes, however, preferring to look at extensions rather than separate buildings. That said, each planning application is judged on its own merits, so here’s how to increase your chances of approval.

Don’t go bigger than you really need to

And it’s safe to say that it is sometimes difficult to control that inner desire to self-build and go as big as possible.

While you have control over the layout and floorplan, as well as the pitch of the roof, the flooring, the kitchen design and so on, you’re not building the Taj Mahal, so rein in your grander ideas. Any annexe must be subordinate and ancillary to the main house – keep the footprint of the annexe as small as you can.

You also need to remember that your annexe must share facilities like water, sewerage and electricity with the main building. It also can’t be sold separately to the main house. 

Make sure you have enough power

As your annexe will have to share the electricity with the main building, you might need to upgrade your electrical supply if it doesn’t have enough juice for both, or if the main fuse board doesn’t meet current building regs. 

All of the electrics must pass Part P regulations to maintain safety.

A good tip is to measure the distance between your indoor meter box and the location you’re planning for the annexe. Under 15 metres usually means the cost of the connection is included in the build cost while there’s a small charge for each metre over 15 metres.

Sewerage and mains water connections

You might be lucky and have all of your mains services together within a convenient little location. However, many people don’t know where their mains sewer and drains are, so if you don’t know, ask your contractor to look for them and explain what their locations mean.

Once you know where everything is, plot them out and measure how far they are from your would-be annexe. Your local authority will probably prefer your annexe to be as close to them main building as possible to make connections simpler.

Think about the type of roof your neighbours will want

Pitched roofs are by far the most popular choice for most people BUT you have to consider the overall height of your annexe with a pitched roof that might impact neighbours.

You might want a pitched roof, but your neighbours probably won’t as it could have an impact on them and their garden. Even if you don’t think about your neighbours, your planning authority will and if your roof is too high, your application might fail.

Flat roofs have improved in recent years, with lifespans of 25 years or more, so don’t be put off the idea. A good idea is to go into your neighbour’s garden and imagine what they’ll be looking at once your annexe is up. If it’s likely to block a great view, have a rethink.

Think about wildlife and conservation areas

If you’re in an Area of Outstanding Natural Beauty, a conservation area or your home is a listed building, then you’ll be subject to stricter policies from your planning authority.

It’s not impossible to get planning permission, but it may be more onerous and expensive to meet the local requirements. You might need to use particular materials, for example.

You need to remember that your planning authority is going to prioritise wildlife and plants way above any human needs and if you have bats or you live near a Site of Specific Scientific Interest (SSI) then you might be out of luck.

Make sure deliveries can get to your garden

Annexes are large structures that will need several larger vehicles to deliver them. Getting to your home and garden might present logistical difficulties. Fortunately, larger vehicles can offload onto smaller vehicles or, if necessary, a crane can enter the proceedings to drop the annexe into its place.

You may also need a skip and a portable toilet for the installation teams, so think about how large and small vehicles could get into and out of your road and garden and discuss everything with your building team.


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