Correct Area measurement of exempt development

FOXFISH1

Folks,
The max area of an exempt development is 40 sq metres.
When calculating this area, is the measurement taken from;

1. the outside surface of the external walls,

or

2. the inside surface of the external walls,

or

3. the outer edge of the gutter?

wazzoraybelle

To the best of my knowledge it's usable internal space.

muffler

Yip. Measured from the inner face of the external walls.

FOXFISH1

cheers lads!
is this mentioned in the building regs or is it common knowledge

smashey

FOXFISH1 wrote: »

cheers lads!
is this mentioned in the building regs or is it common knowledge

Common knowledge.

muffler

Or even this

Section 4 (a)

ircoha

Are we happy that these rules apply to extensions in determining the net floor area of an extension.

They appear to me to relate to the measurement of the areas of houses, with the objective of determining house areas for Stamp Duty exemptions and not necessarily extensions.

I accept the general principle of internal rather than external as per the OP's question but wonder about including internal wall areas.

from the link provided by Muffler:

4. (a) For the purposes of section 91A(1)(b)(i)(I) of the Act, the total floor area of a house is its gross floor area measured inside the finished external walls including the areas specified in sub-article (b) and excluding the areas specified in sub-article (c).
(b) The following shall be included in calculating the total floor area of the house:
(i) all internal walls, partitions, chimney breasts and the stairwell on each floor;

My experience with planners who are asked to adjudicate on whether exempted developments comply is that they exclude internal walls and measure between skirting boards.

In one case where the area was very close to the limit, fitting skirting made from 4 by 2 PAO got the net measurement inside the 40 sqm, after netting out the interior walls.

Mellor

The abovewas brought in rlation tostamp duty, afaik, but it applies to all floor calcs.
it appears else were.
There is also gross, the difference being stair wells etc.

For some are calc, (not exeptions) the outer surface is used

FOXFISH1

Thanks for this input lads,
Before i started planning the extension i spoke briefly to a council engineer on the phone and this was one of the questions that i put to him.
He was of the opinion that the area is measured to the outer edge of the external walls and that some engineers even measured to the outer edge of the gutter.
Obviously i want to be 100% certain on this and i think the above reference gives me a strong arguement.

Also just found this comment in
S.I. No. 306/1991:
BUILDING REGULATIONS, 1991.

"4. In these Regulations—

"floor area" in relation to a building means the area bounded by the inner finished surfaces of the enclosing walls, or, on any side where there is no enclosing wall, by the outermost edge of the floor on that side and in calculating the area of a building or part of a building there shall be included in such area the space occupied by any walls, shafts, ducts or structure within the area being measured;"

muffler

FOXFISH1 wrote: »

Also just found this comment in
S.I. No. 306/1991:
BUILDING REGULATIONS, 1991.

"4. In these Regulations—

"floor area" in relation to a building means the area bounded by the inner finished surfaces of the enclosing walls, or, on any side where there is no enclosing wall, by the outermost edge of the floor on that side and in calculating the area of a building or part of a building there shall be included in such area the space occupied by any walls, shafts, ducts or structure within the area being measured;"

That is spot on.

RKQ

Check out :- S.I. No. 181 of 2000.
LOCAL GOVERNMENT (PLANNING AND DEVELOPMENT) REGULATIONS, 2000.
It gives clear details with regard to first floor areas, house type, distance of proposed windows from boundaries, balconies etc.
To say you can build what you like, as long as its under 40sqm, would be very wrong!

Floor area is clearly defined above in S.I. No. 306/1991:
BUILDING REGULATIONS, 1991.
"floor area" in relation to a building means the area bounded by the inner finished surfaces of the enclosing walls.This is correct as clarified above.
I think the Council "Engineer" is mistaken. Never heard of anyone meassuring or defining area by the gutter! Just wouldn't make sense.

ircoha

Further to the material above the relevant links are as follows:

306 0f 1991
http://www.irishstatutebook.ie/1991/en/si/0306.html
86 of 1994
http://www.irishstatutebook.ie/1994/en/si/0086.html#zzsi86y1994
181 0f 2000 { This is v short, main item is increasing area to 40sqm from 23sqm}
http://www.irishstatutebook.ie/2000/en/si/0181.html

Mellor

RKQ wrote: »

Check out :- S.I. No. 181 of 2000.
LOCAL GOVERNMENT (PLANNING AND DEVELOPMENT) REGULATIONS, 2000.
It gives clear details with regard to first floor areas, house type, distance of proposed windows from boundaries, balconies etc.
To say you can build what you like, as long as its under 40sqm, would be very wrong!

Nobody said you can build what you like as long as its under,
and if they did it would last all of 5 mins before it was shot down

But in general, the 40m2 extension and the 25m2 garden are the physical limits, and the rest is (in general) designable

Floor area is clearly defined above in S.I. No. 306/1991:
BUILDING REGULATIONS, 1991.
"floor area" in relation to a building means the area bounded by the inner finished surfaces of the enclosing walls.This is correct as clarified above.
I think the Council "Engineer" is mistaken. Never heard of anyone meassuring or defining area by the gutter! Just wouldn't make sense.
[/QUOTE]

As an aside, some places use the eaves, and it leads to cutting corners and defects,

The outer edge of the outer leaf is used for coverage area, its possible that the person in the LA was refering to this

RKQ

Mellor wrote: »

Nobody said you can build what you like as long as its under,
and if they did it would last all of 5 mins before it was shot down

But in general, the 40m2 extension and the 25m2 garden are the physical limits, and the rest is (in general) designable
[/left]

Just making sure a lay person doesn't "mis-quote" this site.

Unfortunately when people discover they don't need planning permission they automatically assume they can design the extension themselves! This can lead to an ugly extension that does not comply with the Building Regulations.

Sometimes a little knowledge can be a dangerous thing.

Mellor

RKQ wrote: »

Just making sure a lay person doesn't "mis-quote" this site.

Unfortunately when people discover they don't need planning permission they automatically assume they can design the extension themselves! This can lead to an ugly extension that does not comply with the Building Regulations.

Sometimes a little knowledge can be a dangerous thing.

I know what you mean, somebody with a 40sqm garden in an old house, filling it with an extension that doesn't comply,
its good that you made it clear, as it prevents them pointing the finger at boards

Builderfromhell

In response to OPs query it's worth remembering that other criteria apply to planning. For example ALL of the extension must be to the rear. If part of it extends to side then planning is required. Also, it must only be single storey.

muffler

Builderfromhell wrote: »

Also, it must only be single storey.

Sorry but that is incorrect and in any event this has nothing to do with the OPs question.

I would prefer to see answers given to the original question of how floor area is determined or calculated. That has been done. I dont see the need to further expand on the matter unless the OP states that he wants additional info.

Mellor

Builderfromhell wrote: »

Also, it must only be single storey.

You can have a rear extension on two storys that is exempt,
and is unrelated to the OPs post