http://www.environ.ie/DOEI/doeipub.nsf/ ... 0House.pdf
don'y forget about commencement notices possible commencement notices to health and safety authority as well as administeration of contracts and understanding what insurances should be in place ect. never mind getting the best value for your money in terms of the getting a well designed addition to your house. a well designed addition will add value in both in terms of resale value.
maximise the potential you have.
employ a professional........ a good one. alot of the recent AAI (architectural Association of Ireland) awards in the more recent years have been for smaller scale house extensions. have a look at them anyway they are published every year in a book available from the riai bookshop as well as alot of other bookshops. and you should be able to see inside how a well designed addition do. Alot of young architects start theur careers doing smaller additions and we don't spend 5 years min in college learning nothing.