Balcony not exempt from planning...
No - specifically excluded from exemption by Part 1, Schedule 2, Column 2, Condition 7. - (Page 156).
7. The roof of any extension shall not be used as a balcony or roof garden.
http://www.environ.ie/en/Legislation/DevelopmentandHousing/Planning/FileDownLoad,8797,en.pdf
PM if you need further guidance.