Adding to a garage....planning permission / Build Regs?

8 Jul 2011
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United Kingdom
I have a detatched garage which i have already extended by 1 metre along the side in the direction of my property boundary. I obtained planning permission as it faced the road and came within 1m of the boundary. I also had building regs only to be told afterwards that i didn't need them because the floor area was under 30 sq m.

I now want to add another outbuilding onto the back of this garage extending into my garden to use as a workshop. It will have a floor area of 14 sq m and although the external walls and roof join the existing garage, the only internal join between the two will be a standard 3ft doorway. Other than this, a wall will separate the two.

Am i right in thinking i do not require planning permission or building regs (apart from a part p wiring cert).

I will still have 70% of my garden space left and i already have an extension on my house.

Thanks for any advice
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I've recently done the same thing. If the extension takes the overall floor area (floor area of both the existing garage and the new workshop) over 30m2 then you will require building regs approval. I had to get building regs approval myself as my workshop was 25m2 added to an existing garage of 18m2 making a total of 43m2.

I was originally going to just add a single door between the two but then decided to install a long cantic lintel and a 3 section bifold door meaning me or a future buyer can open it up to put two cars in it if desired although I will mostly only ever open one section of the door.

As for planning permission, if less than 50% of the garden is covered by extensions and outbuildings and it is less than 2.5m high and you are not in a listed building or conservation area then it should not need planning permission regardless of floor area.
Thanks for the response. Things are a bit clearer now but i still have one question.

Wouldn't the 30m2 floor area limit only apply to the new building in the same way that the an extension onto an existing house would refer to the extension only rather than the whole house?
An extension to a house needs building regs approval regardless of the size (except for a conservatory or a porch which have specific exemptions)
Outbuildings under 30m2 are specifically exempt from regs (providing it is built from substaially non combustable matirials or more than 1m from a boundary). Any outbuilding over 30m2 needs regs approval.
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