Neighbour garden house is this legit?

[sageGreen81]

I know you'll probably need a diagram! My mother's neighbour is building a gigantic 3 x 10 m garden house. The garden slopes. The builder has told my DM that where the highest point of the slope is the house will reach 2.48m from ground level. Clearly as it's a slope the overall affect of the property is it's much higher than 2.48 in comparison to my DM's house and she has concerns around privacy, can anyone help?

Do they have planning permission?

Permitted development is 8m for detached or 6 meter on a terrace and 4 meters for some other buildings with a height of 4m (eaves within 2 meters of boundry should be under 3m).

If its 10 meters its over permitted rights.

Isn't a "garden house" an outbuilding? Do same rules apply?

I believe these measurements are for extensions and are with regards to the depth rather than the width.

There are definitely rules on how much garden area can be used though. I'm sure it's up to 50% and think this includes any existing extensions/outbuildings.

From you description it sounds like it is permitted development for an outbuilding. Read the planning portal, and the permitted development technical guidance document on gov.uk.

From memory:
Max height 2.5 m if within 2m of boundary.

On sloping group height is measured from the highest point (technical guidance doc)
max size: 50% of curtilage (garden) which would also include any other extensions or outbuildings.

Building regs apply above a certain size, so the thing has to pass fire regs and stuff (which might make putting windows facing a boundary difficult)

Ok thanks it's the bjt about the metres on the slope I didn't get. Ie he's measured from the highest point of the garden and it's 2.5m above that

Sounds like a Class E permitted development. Height is measured from the highest point adjacent to ground. I always though this meant that if the garden slopes away then the part of the build closest to the house can be 2.5 m with the height at the bottom part being more. If the garden slopes up from the house (less usual) then it would be 2.5 max near the house, reducing in height as it went towards the slope. But I could be wrong about this.

Other considerations are that it must be incidental rather than ancillary, which basically means you can't sleep in it.

Also it can't cover more than 50% of the garden.

If all these are met then they are allowed to build it without planning permission.

So it slopes across the width of the garden one end is top of slope the other end bottom. Sadly can't attach an image.

Highest point is highest point. So the building can be greater than 2.5 meters high everywhere apart from the highest bit of land. See number 2 in this doc: https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=www.diynot.com/diy/attachments/part-1-of-the-gpdo-the-10-worst-permitted-development-loopholes-pdf.160440/&ved=2ahUKEwjj8qXTwaqLAxX9SkEAHXOQA8QQr4kDegQIOhAA&usg=AOvVaw0u5AT3p9RuJy4NJmKgqPSK

Oh right - so if it's 2.5 m on the highest bit of land then that's ok if it's higher from the ground on the other end of the land?

I had a lot of texts from DM she's so sad about it. It's affected her feel of her own garden and she is sad not to have the same outlook.

I can get why she's upset. Hopefully the idea of how it will look will be worse than the reality.

She may feel overlooked but it's doubtful the neighbours will be using the room to stare at her garden. Does she have any idea what it'll be used for?

Yes an office and a shed. But neighbour is avoiding her and rushes off.

If it were me, I’d call the local planning team and talk it through.

But ultimately we aren’t in control of what our neighbours do and whilst it’s normal to feel upset, the neighbour doesn’t owe your mum anything and is within her rights not to want to talk about it, especially as it could be a very awkward conversation if your mum is unhappy.

I bought a house with a view of fields and within 2 years of living here was looking at 4 new build houses. It’s a shame, but it isn’t the end of the world.

I would be gently explaining to mum that once the work is done, you’ll work together to make sure her garden is still useable. Whether that’s putting up extra trellis, or moving her seating position to be somewhere else in the garden.

That's not so bad then. It could have been worse and they were turning it into a bar!

She needs to check and see if the dimensions are allowed under permitted development. 8' isn't that high to screen with plants and the windows will be lower. If the size is within allowed limits, I'd be buying high hedging this weekend.

She spoke to the builders they're a reputable garden house company. It appears it's all legit, DMs house is on a slight hill and she's at the 'top' and her neighbour is much lower so DM's house is about 2ft higher than the neighbour hence DM can see it all from her patio. Sorry can't attach anything. To show!

I'd be heartbroken and politely begging & pleading with the neighbours to re-think this. I'll never understand why people in an office get to decide that someone can simply wipe out the ability to grow plants across one side of their neighbour's garden and there's sod all they can do about it.
If my neighbour built anything remotely like this then I'd be unable to use my new expensive greenhouse without spending £500 on a new concrete base for it at the other side of the garden. I'd be devastated

It's too far gone now

A company selling garden rooms is always going to say it's perfectly fine to build one of their structures. They are not impartial planning consultants. You need to check it out yourself.