Change of use of stables - planning

I'd suggest you talk to a [very] local Geometra, who will know the 'ins and outs' of how your particular Comune thinks/works/applies the rules.You would be unwise to buy it without the Comune's agreement to a conversion - which may well be possible if the correct approach is made to them.Going 'over their heads', or relying on amnesties etc is fraught with risks, including upsetting the locals. If the locals are not 'on side', it only takes one phone call to the Comune to really mess things up. [This includes the farmer reporting you as he's sold a stable and you are converting it - he could well see that as a loss of profit to him] So - talk to a Geometra and then Comune [probably through the Geometra]

The last sanatoria (anesty) was in 2004.  There will not be others.  Any permission is at local comunal level, but must pass the Sovrintendenza per i beni Culturali.  Where you are it is highly doubtful you will get change of use.  Also, as a wooden structure on a concrete base, built as an agricutlurual non permanent building, you cannot change it to civile abitazione as it wont be alla norma with regard to antiseismic regulation, geological survey for foundations, genio civile for water and sewage etc etc.  

Old stables Thanks Alan H and thanks modicasa - completely understand - guess I'll have to search for an old pile of stones / rudere  instead!