Permission required to excavate inside house?

preilly79

Hi
I'm toying with the idea of buying a small cottage and digging down about 1.5m for the purpose of constructing a mezzanine floor. can anybody please tell me what permission is required to do such works, if any?

I'm presuming that since excavating would have some effect on the foundation to the neighbouring houses that the owners of those properties would have some sort of involvement. To what extent are they involved?

thanks!

smashey

When going down a certain depth, you'll need an engineer's input.

sinnerboy

Might not be exempt development . May require permission .

Will require to carried out in compliance with building regs irrespective .
DO NOT attempt without
a structral engineer
party wall surveys - photographic and text

ABP ( numerous ) determinations that attic conversions ARE exempt does not help but , even notwithstanding that , I would still think that creating additional space like this will require pemission

Muffler ? Smashey / Mellor ? / Syd ?

smashey

sinnerboy wrote: »

Might not be exempt development . May require permission .

Will require to carried out in compliance with building regs irrespective .
DO NOT attempt without
a structral engineer
party wall surveys - photographic and text

ABP ( numerous ) determinations that attic conversions ARE exempt does not help but , even notwithstanding that , I would still think that creating additional space like this will require pemission

Muffler ? Smashey / Mellor ? / Syd ?

Yeah, I think this would require permission.

preilly79

thanks! appreciate it!

muffler

As it does not fall into the exempted development categories it will require permission.

As was pointed out get yourself a structural engineer but in any event I think its a waste of time and money unless of course the existing house had a lot of dead building below it.

preilly79

muffler wrote: »

As was pointed out get yourself a structural engineer but in any event I think its a waste of time and money unless of course the existing house had a lot of dead building below it.

Hi, can you expand on this as I'm not quite sure where you're coming from. do you mean that the costs involved are too high to justify this?

I have seen this done before and it was very successful from a space-generation point of view, but if there's something i'm not considering please let me know

Mellor

sinnerboy wrote: »

Might not be exempt development . May require permission .

Will require to carried out in compliance with building regs irrespective .
DO NOT attempt without
a structral engineer
party wall surveys - photographic and text

ABP ( numerous ) determinations that attic conversions ARE exempt does not help but , even notwithstanding that , I would still think that creating additional space like this will require pemission

Muffler ? Smashey / Mellor ? / Syd ?

I'd agree. I don't think it is exempt.
Attics are inside the house, so are an internal modification. Going down however is increasing the external a size of the house, so planning needed. Its a strange one, and i'm not even sure how you would calculate the area of extension (a simple example).

If its a good idea or not, I can't really comment without seeing plans of existing and proposed.
How would mezz level be reached?

sydthebeat

How are you going to get a digger in there???

You will probably end up doing so much alterations to the existing structure that it wouldnt be economical to hold onto it (the structure).....
......Plus this new ground floor wont have any accessible windows for viewing from (seeing as it will be 1.5m below existing floor level)... i dont know if id want to live with such a room....

muffler

muffler wrote: »

As was pointed out get yourself a structural engineer but in any event I think its a waste of time and money unless of course the existing house had a lot of dead building below it.

preilly79 wrote: »

Hi, can you expand on this as I'm not quite sure where you're coming from. do you mean that the costs involved are too high to justify this?

I think what muffler means is if the existing foundations are only 1m deep for example you would have to pay for new deeper foundations, be like building a celler under an existing building; extremly expensive.

If you're lucky, the existing foundations go 3m or so down then the costs are mainly excavation of fill floor & tanking etc.

Slig

If your going underground with living space then you will need some form of tanking, preferably on the outside if you extend below the water table. Drylining is NOT tanking!
The rising walls will now become retaining walls if they extend below 1m as stated above. If they arent suitable (and most old cottages dont actually have conventional foundations) then you are looking at underpinning which is a very costly and time consuming job. There are also stricter building regs for basements with regards to ventilation and access. There arent a lot of basements in Ireland because it is generally much cheaper to go up a storey than down.

muffler

preilly79 wrote: »

Hi, can you expand on this as I'm not quite sure where you're coming from. do you mean that the costs involved are too high to justify this?

I have seen this done before and it was very successful from a space-generation point of view, but if there's something i'm not considering please let me know

I think the guys beat me to it. Yeah - all my concerns would be echoed in the posts above.

Schooby

lads lads lads lads!!

always start with the act before worrying about the regulations

Planning and development act 2000;

4.—(1) The following shall be exempted developments for the purposes of this Act—

(h) development consisting of the carrying out of works for the
maintenance, improvement or other alteration of any
structure, being works which affect only the interior of
the structure or which do not materially affect the external
appearance of the structure so as to render the
appearance inconsistent with the character of the structure
or of neighbouring structures;

is this clear in the case of a basement/excavated ground floor?

If you are not confident in the interpretation of this section with regard to your case you can under section 5 of the planning apply to either the planning authority or the bord to clarify the specifics of the case.

sinnerboy

now why didn't i think of that ?

preilly79

Thanks to all of you! a lot of my questions have been answered, and yet more have opened up!

I guess the thing to note is that there's little use in me speculating without an engineers report.

somebody asked about how the mezzanine floor would be achieved: I envision removing some brickwork from two locations on either side-wall and putting in lintles, on which two RSJ's would span the full width of the house. between these RSj's would be the floor joists. either a pre-cast concrete stairs or wooden stairs would give access to the mezzanine floor. I had also toyed with the idea of raising one pitch of the roof above the mezzanine level to give a little extra headroom.

Dutchy1

Our house is situated on a hill and had a 2.1 metre height basement underneath the living area. Basement was accessible from two sides, the other two sides are underground (under the top side of slope).

We consulted with architects and others who told us we didn't need planning permission to dig down to make the basement habitable. We did just that. Digging down about 70cm, to create a finished 2.4m room height. Underpinning where the foundations were not deep enough. Installing water proofing, radon barrier and drylining. PS - we got a tiny digger in through the basement door.....windows are going in next month so we should be moved down there before the winter. Structural engineer essential. Good luck.