40sqm outbuilding permission?

[d438a1]

Hi there, 

 

I'm after confirmation that I don't need planning permission for a 40sqm workshop. It seems people confuse that anything over 30sqm requires both planning permission and building regulations?

 

The house I'm in is within green belt, but previous to buying it I got confirmation from the council that I still have permitted development rights. All other aspects I'm complying with, i.e more than 2m from boundary so can have pitched roof and also overall curtailage is fine. 

 

Thanks

[DevilDamo]

The 30sq.m doesn’t have anything to do with Planning. If you have Class E PD rights and the outbuilding complies with the PD requirements, then Planning would not be required. You could submit a Lawful Development Certificate application to confirm it is PD.

[IanR]

37 minutes ago, d438a1 said:

I'm after confirmation that I don't need planning permission for a 40sqm workshop. 

~~~~

The house I'm in is within green belt

If it's confirmed you have PD Rights then it should be OK, however at 40m² it could be getting to a scale where it being "incidental to the enjoyment of the dwellinghouse" could be called into question, depending on its intended Use and the size and occupancy of the dwellinghouse.

It may be worth submitting for a Certificate of Lawful Development if there's any doubt on its Use being "incidental".

[d438a1]

Ok thanks for feedback 

[phykell]

On 04/06/2025 at 11:36, IanR said:

If it's confirmed you have PD Rights then it should be OK, however at 40m² it could be getting to a scale where it being "incidental to the enjoyment of the dwellinghouse" could be called into question, depending on its intended Use and the size and occupancy of the dwellinghouse.

It may be worth submitting for a Certificate of Lawful Development if there's any doubt on its Use being "incidental".

Just wanted to confirm this as that's exactly what's happened to me despite my planned outbuilding conforming (and confirmed by the LPA) to all of the permitted development rules.

Here's the well-used (Planning Inspectorate) Emin example (there are a couple of others):

https://acp.planninginspectorate.gov.uk/ViewDocument.aspx?fileid=31950647#:~:text=In the Emin case it,dwellinghouse provides for primary purposes.

Skip ahead to the appeal conclusion which includes:

"I conclude that the outbuilding would not be required in its entirety for incidental purposes. In addition, the size of the building would be much larger than would genuinely and reasonably be required to serve its specified incidental purposes. As such it would not be permitted development by virtue of Schedule 2, Part 1, Class E of the GPDO."

Makes a joke of the PD rules really and allows for a potentially vexatious planning officer and/or planning department to impose its subjective opinions on domestic permitted development.

[Roger440]

1 hour ago, phykell said:

Just wanted to confirm this as that's exactly what's happened to me despite my planned outbuilding conforming (and confirmed by the LPA) to all of the permitted development rules.

Here's the well-used (Planning Inspectorate) Emin example (there are a couple of others):

https://acp.planninginspectorate.gov.uk/ViewDocument.aspx?fileid=31950647#:~:text=In the Emin case it,dwellinghouse provides for primary purposes.

Skip ahead to the appeal conclusion which includes:

"I conclude that the outbuilding would not be required in its entirety for incidental purposes. In addition, the size of the building would be much larger than would genuinely and reasonably be required to serve its specified incidental purposes. As such it would not be permitted development by virtue of Schedule 2, Part 1, Class E of the GPDO."

Makes a joke of the PD rules really and allows for a potentially vexatious planning officer and/or planning department to impose its subjective opinions on domestic permitted development.

I think I'd be challenging that. Who's to decide what is "big enough"?

 

Depends what you want to do, surely?

[Tony L]

3 hours ago, phykell said:

that's exactly what's happened to me

Are you saying you were refused a PD cert? How big was your proposed outbuilding?  The one described in the link is 375m2, which is very different from 40m2.  I don't know what @d438a1's workshop is for, but if it's to work on cars, for example, you could fit two cars in there, but then there wouldn't be enough room to work on them.

[Temp]

Perhaps you've seen it but there is quite an extensive guide here on what you can/can't do without planning permission..

 

https://www.gov.uk/government/publications/permitted-development-rights-for-householders-technical-guidance

 

See page 41 onwards. 

[phykell]

On 09/06/2025 at 16:07, Roger440 said:

I think I'd be challenging that. Who's to decide what is "big enough"?

 

Depends what you want to do, surely?

It's under appeal, all the documents have been submitted so I'm just waiting for a decision from the Planning Inspectorate.
 

On 09/06/2025 at 18:05, Tony L said:

Are you saying you were refused a PD cert? How big was your proposed outbuilding?  The one described in the link is 375m2, which is very different from 40m2.  I don't know what @d438a1's workshop is for, but if it's to work on cars, for example, you could fit two cars in there, but then there wouldn't be enough room to work on them.

I was refused a certificate of lawful development for an application which met all of the criteria for Permitted Development, yes.

The outbuilding I want to build is just over 200sqm but it's to incorporate a three-bay garage and an existing 68sqm (reduced to 44sqm) swimming pool.

The only PD metric which applies to the overall size of an outbuilding is the 50% curtilage rule. Unfortunately, what you say you want the outbuilding for, how you're going to use the space, and so on, is all rather subjective from the LPA's perspective and it's this weakness that some council planning officers will leverage to refuse an application. 

[JohnMo]

5 hours ago, phykell said:

200sqm

How can that be done under permitted development - that's a big house size of building.

[SBMS]

9 hours ago, phykell said:

It's under appeal, all the documents have been submitted so I'm just waiting for a decision from the Planning Inspectorate.
 

I was refused a certificate of lawful development for an application which met all of the criteria for Permitted Development, yes.

The outbuilding I want to build is just over 200sqm but it's to incorporate a three-bay garage and an existing 68sqm (reduced to 44sqm) swimming pool.

The only PD metric which applies to the overall size of an outbuilding is the 50% curtilage rule. Unfortunately, what you say you want the outbuilding for, how you're going to use the space, and so on, is all rather subjective from the LPA's perspective and it's this weakness that some council planning officers will leverage to refuse an application. 

What was the size of your dwelling house?

[phykell]

18 hours ago, JohnMo said:

How can that be done under permitted development - that's a big house size of building.

The property is well over an acre in size so the outbuilding's less than 5% of the available space. Indoor swimming pools are typicaly PD and don't require PP. 

 

14 hours ago, SBMS said:

What was the size of your dwelling house?

Just under 180sqm so the outbuilding is bigger but understandable if the latter's housing a swimming pool.

I would add that it's worth the OP justifying his workshop's area perhaps by giving some detail on the machinery/storage, etc. that the workshop is intended to include - I think the lack of detail on my original application gave my LPA the excuse it needed to reject my lawful development certificate, costing me a a great deal of time, inconvenience, effort and money.

[JohnMo]

4 minutes ago, phykell said:

property is well over an acre in size so the outbuilding's less than 5% of the available space.

Isn't it based on the actual property size - not the land size, you are quoting land size. Unless you actually have a 100 bed mansion

[garrymartin]

21 minutes ago, JohnMo said:

Isn't it based on the actual property size - not the land size, you are quoting land size. Unless you actually have a 100 bed mansion

It's based on two things, I believe - not more than 50% of the garden, and subordinate to the main dwelling.

[phykell]

23 minutes ago, JohnMo said:

Isn't it based on the actual property size - not the land size, you are quoting land size. Unless you actually have a 100 bed mansion

PD requirement is for <=50% of the "curtilage" (area of land around a house and forming one enclosure with it). In other words, 50% or less of what's left after the main dwelling's area is subtracted.

1 minute ago, garrymartin said:

It's based on two things, I believe - not more than 50% of the garden, and subordinate to the main dwelling.

Yes, "subordinate to the main dwelling" is a potential minefield - it can apply to scale but not necessarily. As an example, whilst my outbuilding may have a larger footprint than the main house, the outbuilding is a single storey and doesn't look like a primary dwelling (primary dwelling also has a greater volume). Also, crucial to ensure it's “for a purpose incidental to the enjoyment of the dwellinghouse“.

[SBMS]

9 hours ago, garrymartin said:

It's based on two things, I believe - not more than 50% of the garden, and subordinate to the main dwelling.

GPDO does not reference subordinate. The operative phrase is 

 

required for a purpose incidental to the enjoyment of the dwellinghouse

 

The term subordinate comes from case law and planning appeal decisions, not the legislation. It is used by Inspectors and courts to help interpret what “incidental” means in practice. I think in the instance referenced it’s hard to imagine an outbuilding that is larger than the dwelling house being incidental, Even including a pool. A 10mx5m pool for example would be 50m2… a 200m2 pool room is enormous. 

[DevilDamo]

20 hours ago, garrymartin said:

It's based on two things, I believe - not more than 50% of the garden, and subordinate to the main dwelling.

Many more than two things. It has to comply with Class E of the GPDO.