Guest house/ garden office or shed in a small garden

[gambo]

I live in a typical estate with a back garden measuring around 10x12m. For some time we were planning to do extension but given today's prices I don't feel it's worth it. On the other hand I always wanted to have a garden room/office which I could use for work, but I don't want the hassle of running to toilet to the house so it needs a proper toilet (ideally) with shower. I would also use it as a guest house when someone visits us.

How much hassle is it to get permission for something like this? The plan would be to get it very well insulated and heat using some small ASHP but if it's well insulated anything will probably be good enough even a candle if it's just 10-15m2.

[Temp]

Take a look at the rules on "Permitted Development". You may not need planning permission. 

 

However the rules are moderately complex. If in doubt post details here of the dimensions and we can comment.

 

The building shouldn't be too self contained. Eg if you put a kitchen in it as well as a bathroom the planners might object. 

[JohnMo]

Look for a summer house, most are designed to take advantage of  permitted develop.

 

Even a u value of about 0.2 you only need about 6 to 700W to heat to 21.

 

My sister has one and with two of them in it, and a few candles, it really warm.

[gambo]

I've read number of pages and they say "in most cases you do not need planning permission". I can make it up to 15m2, given it's a measure of internal space, and <2.5m height. Kitchen is not required but would it be easier to do it without and perhaps years later apply for permission if I kick out kids from house?

 

I've attached a quickly created plan where the house would be (red box), also where the man hole is (blue dot). Boiler is very close to the man hole and the room is roughly 6-8m from house. Not sure electricity is an issue but I could use PV to power it + 1 battery as backup.

 

[Temp]

Planning Permission and Building Control Approval are two different things.

 

The 15sqm issue is normally a Building Regs issue rather than Planning Permission issue. I don't think there a limit on floor area for planning other than:

 

A) it must not use more than half the area of the original garden.

B) it must be what they call incidental to the original house. Eg not so big its virtually dominating the house or capable of being a dwelling in it's own right. 

 

I don't think either are likely to be a problem for you. I believe you can buildi bigger than 15sqm under permitted development.  

 

However there are limits on eaves and ridge heights under permitted development and this can be an issue if you want a pitched roof or lots of insulation. The bigger the footprint the lower the roof pitch works out. If you want decent insulation the eaves height limit for buildings near the boundary might be an issue. Eg a 2.5m high roof with 300mm of insulation gives a ceiling height of 2.2m which is a bit low. Less 8f the floor is above ground level. Perhaps keep it away from the boundary so the eaves height can be higher? 

0

As for Building Control Approval..

 

https://www.planningportal.co.uk/permission/common-projects/outbuildings/is-building-regulations-approval-needed-for-an-outbuilding

 

Quote

 

Is building regulations approval needed for an outbuilding?

 

If you want to put up small detached buildings such as a garden shed or summerhouse in your garden, building regulations will not normally apply if the floor area of the building is less than 15 square metres and contains NO sleeping accommodation.

 

If the floor area of the building is between 15 square metres and 30 square metres, you will not normally be required to apply for building regulations approval providing that the building contains NO sleeping accommodation and is either at least one metre from any boundary or it is constructed substantially of non-combustible materials.

 

 

So you will need Building Control Aporoval if its going to have a bedroom. Also because it has drains.  

[SteamyTea]

17 hours ago, gambo said:

Kitchen is not required but would it be easier to do it without and perhaps years later apply for permission if I kick out kids from house?

Don't make it too comfortable.