Exempted development application for 25m2 garden shed

I thought exempted meant you don't have to apply for permission.

From your description it would appear to be exempt. However you should check the development plan for the area to establish if there are any restrictions regarding such structures. Also be aware that the planners could take the view that the flat roof doesn't match the house although it would be unlikely.

You will require plans drawn to scale together with location map and site layout plan.

You can build an exempt extension and a separate exempt detached shed/garage. However converting an existing garage to habitable accommodation and building an extension are lumped together for floor area calculations. The combined floor areas in those situations would normally exceed the 40 sq metre threshold.

The floor is calculated on the basis of the internal measurements. The Section 5 declaration is normally only looked for when there is a doubt regarding the status of the building. If say you're safe enough to proceed with building.

If a family demolished a shed and just had a lawn and then sometime later decided to build a new shed, how would a council even know they previously had a shed in the garden or what size it was? That's like saying any old wooden shed that was removed because it was derelict from weather or falling down or unusable at any earlier time would be included in the exempted measurements. Common sense would say it can't be counted if it's gone.

Being bolted down is irrelevant. As is size. I was referring to the requirements for class 3 structures.

Most people would plough ahead. I wouldn't be concerned myself as I know that LAs around me agree that it resets. I was just pointing out that the regulations don't actually say it resets. If there are is nothing borderline, with the rest of the requirements, there isn't much point. But it's only 80euro at the same time.

Does a 'garden room' less than 25 sq.m come under Class 3 if it is used as a Play Room, an Office or as a Gym subjec to the usual height and residual area restrictions?

IMHO it doesn't but perhaps I'm wrong. I appreciate that it can be used as a shed and could always be retro converted - a dear shed, though

Class 3 is not restricted to sheds.

…any tent, awning, shade or other object, greenhouse, garage, store, shed or other similar structure.

…The structure shall not be used for human habitation…or for any other purpose other than a purpose incidental to the enjoyment of the house as such.

The above permits games room, office, gym etc. All are incidental to the enjoyment of the house.

FYI If they were not exempt. Then retro converted afterwards would not be possible. In order to do that it would have to be permitted originally, or have an additional exemption for conversion.