Limit to the size of house extension?

Redbedhead

We have just seen an architect to quote for doing the plans for the house extension we would like. He mentioned in passing about there being a limit as to the size of extension you can have depending on the size of the plot. He couldn't tell me what the limits are off the top of his head but I figured I could find them on the local council website but am struggling at the moment. I will ask him when he comes back with his quote but I was wondering if anyone on here had an idea?

To put it in context we are looking at adding a double storey extension that is about 17ft by 23 ft to the back of our house which is currently about 23ft by 23 ft with some additional outbuildings that will be knocked down to make way for the extension. The overall plot size is about 45ft by 250ft.

Thanks

System

Redbedhead wrote: »

We have just seen an architect to quote for doing the plans for the house extension we would like. He mentioned in passing about there being a limit as to the size of extension you can have depending on the size of the plot. He couldn't tell me what the limits are off the top of his head but I figured I could find them on the local council website but am struggling at the moment. I will ask him when he comes back with his quote but I was wondering if anyone on here had an idea?

To put it in context we are looking at adding a double storey extension that is about 17ft by 23 ft to the back of our house which is currently about 23ft by 23 ft with some additional outbuildings that will be knocked down to make way for the extension. The overall plot size is about 45ft by 250ft.

Thanks

not sure that there is a set limit, i've had discussions with planners about what over-development of a site is by definition and never got a straight answer, i know with a new house they don't usually like to have anything less than 100sqm amenity space, but good luck getting a solid answer from the council!

Redbedhead

Thanks! The architect has suggested approaching the council for pre-planning application advice so I would hope they would say at that point if it is was 'no-go'! I will be asking the architect when we next speak to him, to see if he has found the numbers somewhere!

Doozergirl

Why does he not know that?

Off the top of my head I can tell you that you can't build on more than 50% of your 'original' garden space and that any double storey extension will not be able to project more than 45 degrees out from the middle of any of your next door neighbours upstairs windows. Not without pushback.

System

Doozergirl wrote: »

Why does he not know that?

Off the top of my head I can tell you that you can't build on more than 50% of your 'original' garden space and that any double storey extension will not be able to project more than 45 degrees out from the middle of any of your next door neighbours upstairs windows. Not without pushback.

erm.....that doesn't apply to every local plan around the country! best get the correct advice from the local authority with a pre-planning app.

iamcornholio

There arte no limits if you apply for permission - it's assessed on its merits

But large extensions normally get trapped by other restrictions such as the 45 degree rule, distance to adjacent properties and the main one ... massing and dominance..

Basically planners do not like extensions more than 1/2 the size of the original house

Waterlily24

We're just building an extension, and we weren't allowed to build the extension bigger than one third of the existing footprint. We originally put plans in for a much bigger extension about twice the size of the existing footprint (as was) but it was thrown out, that's when we were told about the one third. The strange thing was that if we pulled the old bungalow down and built new it would have to be even smaller. We have a very large garden and no near neighbours, the garden size didn't come into it at all for us.

We are called 'Countryside' not sure if this makes any difference.

ormus

there are no rules set in stone. every local area has a different view on the main rules.
not only that, they change the local rules with the seasons, too.
i remember one area that used to use a 25% rule. then it was 33%.
ive heard of other areas using the 50% rule.

my own house has a treble room extension. you certainly would not get that passed today.
(in my area).

GClyde

There are national guidelines in the form of Planning Advice Notes (PAN's) and ecah local authority has to interpret them accordingly. So you may find slight variations from one LA to the next. My advice to you would be to speak to your local planning officer to see if your project is feasible before paying an architect to do plans, only later finding out that your project is refused. In other words, do some leg work of your own first before spending loads of money.

Regards

Graham