± 40 sq.m. exemption from SI.9 | Kevin Tyrrell Architectural Technologist



The following opinion piece was originally submitted by Co. Wexford-based Architectural Technologist, Kevin Tyrrell, to the BRegs Blog as a comment on another post on 2nd November 2014. With his agreement, some editing and a few additions from the author we have formatted into a post here as his case was so well put.

Having read the articles and scare mongering of the last few days in relation to the situation with regards to extensions to dwelling houses, I really have a problem with how the Building Control Authority are viewing no. 1 “a dwelling” and no. 2 “an extension” in relation to S.I.9, because they are redefining them to suit themselves and causing a lot of chaos in the meantime. The following is my attempt to make sense of what each is and how they relate to Commencement and Building Control, specifically in relation to (a) extensions below 40 sq metres and (b) the issue of a cumulative total area of 40 sq metres ,being the total area of all extensions no matter when they were built, which they claim a further extension to the dwelling (which brings this total area above 40 sq m) being commenced triggers full compliance with S.I.9 by the parties involved. That is what I am attempting to sort out, so please dont take this as a legal interpretation, this is just me teasing out the process and relationships of how an extension to a dwelling house relates to S.I.9 and Commencement Notices from the most logical point of view that I can take.

S.I.9 states that its provisions ONLY apply to the following with regards to extensions : an extension to a dwelling involving a total floor area greater than 40 sq metres. Now…to me “an extension” is a singular entity that goes to make something bigger, but until it is comlpete and formally part of the whole at completion, from the view of S.I.9 it has a specific definition. It is an extension which has had Planning Permission granted and is due to be built under the regulation of S.I.9. That is all and entirely what it is. And the crux of the matter relies heavily on this and also a few other facts relating to specificity.

A commencement notice is linked to a specific Planning Application, with a specific register number and attached plans and documents. The two are intrinsically linked and the Commencement Notice refers only to the Planning Permission it is linked to. The Commencement Notice was always the mechanism by which 2 things were alerted to the County Council.

  1. That it was due its contributions and any further information listed in planning conditions must be complied with.
  2. And that the applicant was ready to build on site.

A Commencement Notice is and always has been a project specific entity, and is not and never has been linked to anything else on site.

The Planning Regulations have not changed or been altered in any way, so in actual fact a person can view 2 separate extensions under 40 sq metres as strictly 2 different entities, and as long as they satisfy the Planning and Development Act and Regulations then the amended Building Control Regulations should have nothing to say about them.

The amended Building Control Regulations are not a commentary on Planning Regulations, they are regulations governing the Building Process and how it should be undertaken.

The Planning and Development Regulations deal with the extension in relation to the whole house and its environment, the Building Control Regulations do not and never have. So it is intrinsically impossible in any way to have a link to anything else going on with the development in any way, because of one simple thing….A Commencement Notice is Project and Planning Permission Specific…and doesn’t and cant relate to anything else. It Stands Alone.

To suggest otherwise is scare mongering…and it says nowhere in the Building Control Amendment Regulations that other extensions or a cumulative size must be taken into account.

Why? Because it cant. Why? Because its Planning Permission Specific.

And I believe that because Building Control Regulations relate and comment only to a single Permission then they can have nothing to say about the cumulative size of any extensions on the house. You could have a total of 300 sq metres of extensions to the house and they may as well not exist at all as far as the Building Control Regulations are concerned.


Because prior to applying for permission the house was seen as a whole, a single dwelling. Not a dwelling with x amount of extensions and other alterations. It is and has to be viewed as a whole object. A House, a dwelling. And since I stated previously the Commencement Notice is Permission specific it relates to an extension to a dwelling…not a dwelling (as was originally granted permission under such a permission), and has been extended and altered under a different one in the past.

Specificity destroys the argument against there being a link to previous extensions which have been granted permission or are pre- 1962 or whenever Planning Regulations came into effect. As long as the dwelling house has been granted permission for its various extensions and alterations it must be seen as a specific single thing…a dwelling house, the sum of its parts.

So as S.I.9 deals with only “an” extension to “a” dwelling which is specifically linked to a single Planning Permission, it can not comment on any other previous extensions. Well….thats how I see it in a logical and hopefully a legal and regulatory sense anyway.

Only Planning Regulations exist to comment on the entire development and how a specific permission relates to the whole. If its being seen otherwise then Building Control Regulations are supplanting Planning and Development Regulations.

Other posts of interest:

Commencement notice problems | Does size matter?

Legal Alert | Commencement Notices since 1st March 2014 

3 County Councils ask Minister to Revoke SI.9

Commencement Notices – Update | 22 October 2014

Catch 22 Commencements 

Owners may need a Certifier for a Porch?

“Dangling Participles” and why all extensions may now require compliance with S.I.9: 2014

S.I.9 – Where are we now? 27 October 2014 

Press: RIAI fearful Local Authorities will start “finding something to invalidate as a method of workload control”

10 thoughts on “± 40 sq.m. exemption from SI.9 | Kevin Tyrrell Architectural Technologist

  1. Michael O'Neill

    Let me preface this by saying I am an unregistered architectural graduate of 24 years post qualification experience and not a solicitor, barrister or judge.

    I make this reply to tease out the apparent weaknesses of the above argument to try to get to the bottom of this.

    The Specificity argument may be seen as a sound argument to make the above particular case. However…

    The original exempted development provisions under the Planning and Development Regulations were a matter of convenience for the Local Authorities – they didn’t want the system to be clogged up dealing with a myriad of small works.

    Accordingly provision was made in the Planning Regulations for various classes of exempted development including house extensions, with several rules of thumb.

    This guidance was intended to provide some sort of a balance between the private need for extending a residence and the public good of not infringing too much on the amenity of an adjoining or neighbouring property.

    In allowing exempted development at all, the law is following the de minimis rule:

    “de minimis non curat lex”

    “the law does not concern itself with trifles”

    However, there were some strict limits set in place. One of these was the absolute limit for extending a property under the exempted development legislation – 40 sq.m.

    Thus exempted development was assessed cumulatively such that the limit or 40 sqm (and this varied over the years) referred back to

    (i) the original plan of the house at a date if it was Pre-’63 or

    (ii) the original permitted plan after 1963 ‘sans’ later extensions.

    Why was there such a limit set and how is this relevant to the Building Regulations and Building Control Regulations?

    Here I believe another argument must be used – the “reductio ad absurdem” argument which is more convincing in my opinion.

    Consider an 80 sqm small house on an acre of land. Notwithstanding the existing planning regulation exempted development limits, it could be extended in 39 metre increments infinitely if the argument used in the article above is employed.

    It seems clear that a series of extensions which could cumulatively add up to – say – doubling the house floor area over time should be properly regulated in order to support the public good and the amenity of adjoining sites.

    It is indefensible to suggest that extensions should refer only to the house as it now stands where exempted development is concerned, There must be an over view.

    While converting a garage under the old legislation constituted exempted development under planning, the building bye laws and later the building regulations still applied.

    The Building Regulations should be in step with the Planning Acts or else this may lead to a fundamental flaw in the governance of the building industry.

    However, taking a wider view, I also believe that the current building regulations impose unfair and unsustainable liability, are far too cumbersome to apply under and administer, offer no acceptable independent assurance to the electorate (i.e. from the Local Authorities) and seem likely to significantly restrict Ireland’s economic recovery.

  2. Hanna Loughnane

    Just to note also –
    The BCMS comments on similar queries about the 40m2 debacle noted that the reasoning behind their “cumulative” argument is that they want to avoid a situation where a person ultimately wants to build, say, a 45m2 extension – and has got planning permission for this – but, when it comes to building, they build the extension in two separate phases so as to avoid their duties under S.I.9.

    Condition 1 of almost every planning permission is that “the development shall be built in its entirety in accordance with the drawings etc. etc.” so the applicant is obliged under planning to build the entire extension in one go.

    Anyway, building your 45m2 extension in two separate phases would probably add a similar cost (and stress!) as would implementing the requirements of S.I.9. I don’t really think people will try to work around the regulations in this way – it’s more trouble than it is worth.

    That then only leaves the case of an extension of, say, 30m2 built say, 25 years ago. A person now wants to build a further 15m2. They require planning as the cumulative area is over 40m2 but, in my opinion, the project does not come under the remit of S.I.9 as the construction project in question is an extension of 15m2. S.I.9 did not exist when the first 30m2 was built in the 1980s and REGULATIONS CANNOT BE RETROSPECTIVE. S.I. 9 is about building control – about controlling construction standards – and, presumably to avoid clogging the system, only concerns itself with domestic projects over 40m2. It cannot control the standard of an extension that is already built and completed before the implementation of these regulations so, in my opinion, extension completed before 1 March 2014 do not exist so to speak and should not be considered as part of the current works.

    Whether the clients of domestic extensions smaller than 40m2 deserve the “protection” of S.I.9 as much as procurers of larger buildings is a question for another day!

  3. Kevin Tyrrell

    Hanna…as I say, because the Commencement Notice is specific to a planning permission, if an extension of 45 sq m was proposed, granted and is seeking to be built it MUST be built under the control and regulation of SI.9. It is an extension to a dwelling larger than 45 sq m and will trigger the full rigours of SI.9. However, if the person wanted to apply for the 45 sq m extension under 2 separate planning applications of say 22.5 sq m and build them at different times, then are they not entitled to avoid the full SI.9 regulations and just send in their commencement notice for each extension and proceed?

    At the end of the day, I’m not arguing on a basis of consumer protection, or finding loopholes to avoid SI.9. I’m arguing from a point of view of what the Building Control Regulations say. Planning and Development Regulations determine what can and cant be built…Building Control Regulations determine how they are built. I am arguing that the Building Control Authorities have been scare mongering and trying to force SI.9 onto developments where within the BC(A)R are specifically mentioned that SI.9 is not required. To me they are trying to re-write the rule book to say something that the rules never mention.

    1. Hanna Loughnane

      I agree Kevin. Furthermore, surely the whole point of exempting extensions under 40m2 was to avoid clogging up the system. The planning exemptions for certain small extensions and the building control exemptions for commercial extensions under 25m2 in certain cases exist for the very same reason. In now saying that small extensions may come under the remit of S.I.9 if the house has been previously extended, BCMS are contradicting the spirit of the legislation and creating a nightmare of additional paperwork for clients, construction professionals and themselves.

      1. Kevin Tyrrell

        The magic number of 40 sq m it seems to me to be rather arbitrary. It is probably fair to say that somebody did think that having all extensions, be they a little front porch, a small sunroom or something that wasnt a major extension to the house going through the BCMS system would be a nightmare to handle and a cutoff point was probably necessary. I think since the 40 sq m is mentioned as the limit for exemption from Planning Permission in relation to extensions they thought it might be a handy number to pick.

        And although the 40 sq m is a cumulative limit in relation to Exemption from Planning Permission (because it takes into account all extensions built without planning permission up to that limit), that the Building Control Authorities think they can apply the same cumulative effect to all extensions, thus having a maximum limit of 40 sq m built onto a dwelling before SI.9 applies.

        You know, it occurred to me today. Maybe somebody in the civil service simply got their wires crossed somewhere and mixed things up by mistake…mixed exemptions from Planning and Development up with exemptions from the BC(A)R, because of them both sharing this magic number of 40 sq m, and now they are simply too proud to hold their hands up and say sorry…our bad!!! Hopefully somebody will wake up and come back to reality on this and simply admit a misinterpretation and set things straight. There are too many peoples lives, professions and peace of mind riding on this to be let continue any further.

  4. jack jack

    All this talk about planning permission is a total red herring which only serves to muddy the waters. It is totally irrelevant.

    The commencement notice is for only the works covered by the notice.

    Article 9(2)(b) seeks a long notice for

    “AN extension to a dwelling involving a total floor area >40m2”

    …note AN extension.

    There is absolutly no reference to any past or present works that may and or may not have been carried out.

    If you carried out a 39m2 extension back in 1993, and now planned to do a 2m extension ….

    ……. why on earth would the poor undersourced BCA need to get full certs of compliance etc for those 2m2

    ………. unless whoever came up with the cumulative rule wants you to go and find the builder and designer from 1993 and now certify the works that they carried out 21 years ago. To even suggest such a course of action is totally illogical.

    Obviously someone who has a single planning for a single 42m2 square extension and who attempts to submit 2 short notices, drawing an imaginary line down the middle of the room is just plain trying to cheat the regulations and will be found out by either the BCA or subsequently by some future potential purchaser down the line.

  5. Michael O'Neill

    Two items

    1. “Regulations cannot be retrospective”:

    The planning regulations look to the past to help determine what you can do in the present.

    Similarly if the building regulations were held to the same criteria, the past-directed look would be required to determine what applies to the current work.

    2. Past Documentation.

    It seems reasonable to state that the standard of document submission required by current regulation cannot be applied to the past work.

    Those documents may be extinct or lost or they may not have been required by a previous submission.

    However, legislation can take account of the extent of past work when determining to what standard the current or proposed work will be held.

    1. Kevin Tyrrell

      In my opinion the BC(A)R are attached to a single entity. Commencement of a development which has been granted planning permission. It cant exist in any other landscape or in reference to anything else…past or present. It is what it is and refers only to one thing, the development referred to in a Planning Permission which is being commenced. The past literally does not exist to it, so it can not comment on it. Its time dimension only exists from the day a Commencement Notice is submitted to the day the client takes possession.

      Planning and Development Regulations refer to and are couched in the landscape of the building, the environment, the neighbourhood, and in certain instances may comment on the past and present of the site and all its evolution from green field to where it is today. Exempted development in Planning and Development Regulations is one of those aspects which can comment on the past and takes the totality of the lifetime of the development into its purview.

      But, Building Control is not Planning and Development, Building Control Regulations comment only on the Planning Permission being commenced…Planning and Development Regulations comment on the planning application to develop and all the aspects of the development. The two are not interchangable and what applies to one in relation to how it can comment on the development of the site, is not conferred to the other.

  6. Michael O'Neill

    It is clear that where an extension is being contemplated, there are two entities – the existing building and the extension. The previously extended status of the existing building is the issue.

    I think people may be taking a significant risk by assuming that “if a thing is not expressly included then it is excluded”.

    The courts will balance the “reductio ad absurdem” principle against the “de minimis non curat lex” principle.

    The courts will tend to err on the side of The Public Good, as opposed to the private need of the owner to develop the extension or the desires of the building professional to avoid the hassle imposed by the current regulations, which may include their eligibility to perform on the job.

  7. david mcgeown

    quick one.
    make a planning application for an extension to a house with no previous extension.
    the extension comprises 30 sq.m. of new development at ground floor plus 20 sq.m.
    of attic conversion works with lets say a dormer thrown in.
    Comes under BC(A)R and its long form commencement notice or not – that is the question?
    Is it exempted development not requiring planning permission anyway – different local Authorities seem to to take different opinions on whether attic conversion floor area counts towards the 40sq.m. I don’t mind putting the above example in for a planning application just to be on the safe side but i’d really not have to drag it through S.I.9 if i didn’t have to and I’d say most clients would feel the same.

    Like the door added to the existing 2 sq.m. open porch to a house with 39 sq.m. extension already built out the back there are so many grey areas in this – or is it just me? Unclear definition seems to mean works technically fall under S.I.9 which surely were never intended to be.

    Not much of a contribution sorry but muddy waters need to be clarified asap especially as there is no retrospective course of action that can be taken unlike in planning where at least a retention application can regularise works later on should difficulty or a difference of opinion arise.


Leave a Reply

Your email address will not be published. Required fields are marked *