Undergroup external garden building

[24sevenv24]

Hi All

There is a very large ditch which runs across the end of the gardens of the houses on my road. The ditch has a very small stream within it (just boggy, no visible water running). The ditch is about 10m long x 5m wide x 8 foot deep. The houses either side of me have installed a concrete pipe to allow the water to flow and have then filled the ditch in to extend their gardens.

I had an idea to build an underground garden building in this space instead. I was hoping to install a concrete pipe and build a water proof building in the space with a sump for drainage. The roof of the building would probably sit 1 meter above ground level and I plan to insulate it, run power to it and use it as a workshop. Would I need planning permission to do this? I would like to make the ditch wider to build a bigger space (may 7 meters wide) however could build as it is today with no excavation required if I need to to stay within the rules.

Many thanks in advance!

 

[Ian H]

I don't know but it would be cool. Even better with a clear plastic pipe or stone built culvert with a clear lid

 

[Nakajo]

It depends on an intepretation of curtilage, for which (helpfully?), there is no legal definition. A plan might help.

 

[tony1851]

I suspect this would need p.p. because it would also be classed as an 'engineering operation'.
There was until recently a debate as to whether basements come within p.d., but a court case determined that because
a considerable amount of engineering work was required (excavation etc) it was not p.d.
Probably a moot point?

 

[^woody^]

It's a classic Planning exam question - "What is 'development' under the TCPA 1990"?

“development,” means the carrying out of building, engineering, mining or other operations in, on, over or under land, or the making of any material change in the use of any buildings or other land.

 

[John D v2.0]

Sounds extremely expensive to build an underground building. Why not build it above ground instead?

 

[24sevenv24]

Hi! Thanks for your responses.

I was hoping that building underground without having to excavate would allow me to build over 15m3. If no excavation is required, can I exceed this as the space already exists? If I build above ground, I am limited to 15m3 and will have to fill the space in anyway, which will cost too...

 

[freddiemercurystwin]

Planning Permission aside at the very least an application to culvert a watercourse would need to be applied for from your local authority or your IDB http://www.ada.org.uk/member_type/idbs/ and I suspect the building of a workshop in a garden would not be considered a good enough reason to get approval. An application is likely to require an engineered solution and possible some flood defence calcs to assess the size of any culvert and ensure its long term reliability.

 

[John D v2.0]

Where dues the 15m³ limit come from?

Your expense for adding a concrete pipe in the base of a normal shed will be minimal compared with waterproofing the structure sufficiently and an engineering solution to holding back the ground, not to mention the extra digging. It's not just a case of making a hole and putting a roof on it.

 

[tomfe]

If your neighbours have contained the drainage ditch then they have already impeded water flow so you doing the same will make no difference.
You can build an underground bunker without planning in England as long as its 5 meters(I think it's 5) from the main residents.

 

[chappers]

If your neighbours have contained the drainage ditch then they have already impeded water flow so you doing the same will make no difference.
You can build an underground bunker without planning in England as long as its 5 meters(I think it's 5) from the main residents.

I think he is saying they have installed a pipe to allow the water to flow and then remade their gardens over the top of the culvert.
Whilst this may be possible, this is still a water course and the course needs to be able to continue unheaded.
Seems complete madness to me to build a building in a water course when you consider the extra costs involved. what about foundations etc the ground it wet and boggy would be totally unsuitable, probably not insurmountable but at what cost.