From:
http://www.irishstatutebook.ie/2001/en/si/0600.html
STATUTORY INSTRUMENT.
S.I. No. 600 of 2001.
PLANNING AND DEVELOPMENT REGULATIONS, 2001
SCHEDULE 2
Article 6
Part 1
Exempted Development — General
Development within the curtilage of a house
CLASS 7
Column 1
Description of Development
The construction or erection of a porch outside any external door of a house.
Column 2
Conditions and Limitations
1. Any such structure shall be situated not less than 2 metres from any road.
2. The floor area of any such structure shall not exceed 2 square metres.
3. The height of any such structure shall not exceed, in the case of a structure with a tiled or slated pitched roof, 4 metres or, in any other case, 3 metres.
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Under Planning Law:
2.0 sq.m. is the limit, within the terms of reference outline above. You may also need to comply with Section 4 (1) (h) of the Planning and Development Act 2000 as amended in relation to your selection of materials. In general these should harmonize with those used on your house or used with similar development locally
Under the Building Regulations:
There are other issues in relation to maintaining disabled access under TGD Part M of the Building Regulations, assuming you have such an access at the moment, including minimum width and level approach to a 1200mm square landing and you need to ensure that the threshold is no more than 15mm high.
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1655,en.pdf
Law of the Land:
Your neighbour's front door may directly abut yours - in an older property for example - and you should consider discussing with them jointly extending both porches or, failing that, agree the installation and weatherproofing details of your porch prior to commencement to avoid unpleasantness and facilitate access for your porch installer.
ONQ.
[broken link removed]