Extension Requirements

kippy

Hi,
Am looking to build an extension on the back of my semi detached two story house.
I have an open space area of approximately 48 Square metres at the back of the house. There have been no alterations to the house since it was built.
What is the biggest single story extension I can build without having to get planning permisssion?
(Based in Galway City)
I had read some of the planning documents and initially thought it would be 12 square metres because I am in a Semi Detached house however rereading them again, I think I could build upto 40 Square metres providing there are no less than 25 square metres left in the back garden.
This would allow me to go to 23 square metres.

Is this correct or have I completely misread the documentation?

Thanks for any help/assistance,
Kippy

muffler

23 sq. m would indeed be the max. exempted size in your case. Just make sure that you comply with all the conditions attached to the exemptions i.e. windows 1 metre from boundary etc and also check your original PP for the house to ensure there are no conditions on it restricting the size of any future extension.

kippy

muffler wrote: »

23 sq. m would indeed be the max. exempted size in your case. Just make sure that you comply with all the conditions attached to the exemptions i.e. windows 1 metre from boundary etc and also check your original PP for the house to ensure there are no conditions on it restricting the size of any future extension.

Thanks Muffler, I will check out those other conditions as well.
I have no idea why I thought I was limited to 12 because I was in a semi detached house.

muffler

The 12 sq. metres comes into play on the first floor of a semi-d or terraced house. Thats the max. you're allowed so you would have read about it alright.

kippy

muffler wrote: »

The 12 sq. metres comes into play on the first floor of a semi-d or terraced house. Thats the max. you're allowed so you would have read about it alright.

Yeah, the "above ground floor" part was confusing me, I must admit.

I had already done up a few options for a 12 SQM extension but the benefits of it weren't there due to the space.
This should open up some possibilities.

It looks like there is a sewer pipe (shared by 3 other houses) running along the back of my wall and I will need to build over this.
Would this impact on planning or would I just need to ensure adequate access was maintained and we did the foundations in such as way as to ensure the pipes were protected?

sinnerboy

There is no "just" about any of this. All construction work must be documented .

Not because of any actions you may fear arising from a Local Authority. They do have sweeping powers but rarely exercise them .

You need to fear the future consequences of future conveyancing. Undocumented works will be very very difficult , if not impossible , to raise finance against. This will become clearer and clearer as we eventually limp out of recession.

So for that reason you are best to hire an Architect , Architectural Technician or Engineer.

( It is possible - with the correct professional advice - to build over drains)

mickman

GUys

I am in the same boat here.

Does it mean that you can have 40 square metres on the ground level floor and up to 12 square metres on first floor ?

If so , what is the reason for this ?

If you do run over these numbers, does it just mean you have to apply for planning ? or does it mean that even if you do apply for planning then you wont be allowed do more than this in a semi d ?

muffler

mickman wrote: »

Does it mean that you can have 40 square metres on the ground level floor and up to 12 square metres on first floor ?

No, you can extend to the rear of any house by 40 sq. metres in total without permission providing the house hasn't previously been extended or there are no conditions on the permission granted for the house that would restrict the size of any future extension.

If the house is semi-D or terraced then no more than 12 sq. metres can be on first floor. So in this situation you could extend by up to 28 sq. metres on ground floor and up to 12 sq. metres on first floor. Those are the maximum floor areas and are subject to conditions.

mickman wrote: »

If so , what is the reason for this ?

Primarily to preserve the residential amenities of adjoining properties.

mickman wrote: »

If you do run over these numbers, does it just mean you have to apply for planning ?

Not sure in what context you meant "just mean". Dont take this matter lightly as you would have to apply for retention planning permission and I have seen these refused so its best to check and stick to the regs before embarking on any works

mickman wrote: »

or does it mean that even if you do apply for planning then you wont be allowed do more than this in a semi d ?

The regs clearly state that the original house can be extended by up to a maximum of 40 sq. metres and that includes the ares of any extensions that have been granted permission.

mickman

muffler wrote:

The regs clearly state that the original house can be extended by up to a maximum of 40 sq. metres and that includes the ares of any extensions that have been granted permission.

Thanks for your reply.

Still a little confused about the line above, do you mean that even with planning the house can only ever be extended by 40 sq metres ? Or does it mean that if you get granted planning then you can extend by more than a total of 40 square metres ?

THese are my figures.

Ground level : extend by 14ft x 20 = 280 ft = 26 square metres

First floor : extend by 10 ft x 13 = 130 ft = 12 square metres

So a total of 38 square metres .

We also would have space at the back of the extension around 20 feet by 12 which is 320 ft = 29 square metres

Do these figures look good to you ?

I am taking this matter very seriously indeed, some people have told me to work away and you will be grand but i will not do this unless my i am complying with regulations

sinnerboy

40m2 more than the original house area is the max area of exempted development you can have. So even extensions which are granted permission eat into this 40m2 max.

40m2 is not the max you can seek permission for however. For example I recently obtained permission to extend 190m2 onto a 60m2 cottage.

muffler

mickman wrote: »

Still a little confused about the line above, do you mean that even with planning the house can only ever be extended by 40 sq metres ? Or does it mean that if you get granted planning then you can extend by more than a total of 40 square metres ?

As stated by sinnerboy you can apply for planning permission as often as you like and for whatever size you want but if the permissions are granted then this eats into your "allowance" of 40 sq. metres you can build to the rear without having to look for planning permission.

For example you apply for and get permission to put a 25 m2 extension on the side of your house and in a couple of years from now you wish to build to the rear of the house without planning. In this situation you would be only allowed 15m2 without planning (40m2 limit less 25 m2 already built to side) Of course you can apply for permission if the proposed rear extension is going to be greater than the 15 m2.

Another example - as per above except you apply for and get granted permission for a 45 m2 to side of house. In this situation there is now no exemption for building to the rear. You would have to apply for permission in this case.

THese are my figures.

Ground level : extend by 14ft x 20 = 280 ft = 26 square metres

First floor : extend by 10 ft x 13 = 130 ft = 12 square metres

So a total of 38 square metres .

We also would have space at the back of the extension around 20 feet by 12 which is 320 ft = 29 square metres

Do these figures look good to you ?

On first look I thought it was okay but you miscalculated the amount of open space remaining. 20' x 12' is 240 sq. feet which is 22.3 m2

I am taking this matter very seriously indeed, some people have told me to work away and you will be grand but i will not do this unless my i am complying with regulations

We call that the "billy down at the pub" syndrome

The precise legal details of the exemptions for domestic extensions can be seen here

There is also a handy little leaflet in a Q & A format that can be viewed and/or downloaded here

mickman

The free space

What does this include? Is it only space at back of extension or does it include space at side of extension as extension will only be half of width of main house??

muffler

mickman wrote: »

The free space

What does this include? Is it only space at back of extension or does it include space at side of extension as extension will only be half of width of main house??

Extracted from the conditions attached to the exemptions

5. The construction or erection of any such extension to the rear of the house shall not reduce the area of private open space, reserved exclusively for the use of the occupants of the house, to the rear of the house to less than 25 square metres.

The bit in bold is the relevant piece

mickman

muffler wrote: »

Extracted from the conditions attached to the exemptions
The bit in bold is the relevant piece

sweet :-)

Have loads of space in that case.

Thanks for all the tips

muffler

mickman wrote: »

We also would have space at the back of the extension around 20 feet by 12 which is 320 ft = 29 square metres

muffler wrote: »

20' x 12' is 240 sq. feet which is 22.3 m2

mickman wrote: »

Have loads of space in that case.

How do you make out that you have loads of space if you only have 22.3 sq. metres or am I missing something?

mickman

I wasn't counting the free space at the side of the extension. I was only counting free space behind the extension