Does anyone have any experience of

You will still need a geometra to get all of the necessary permits and approvals.Costs for materials will of course depend on what you plan to build? What will you reuse from the existing structure, ectc

Hi! As Bruno has pointed out, you are going to need a geometry or architect to sign plans, get permits and also licensed tradesmen to sign all relevant certifications that Council may require. Not an easy task, even if your husband is a builder. To rebuild a ruin in Italy is the dream of many people, a dream which may easily turn into a nightmare unless you carefully plan everything. Unfortunately, Italy is full of those half completed renovations. Perhaps you should look into those, as in today's market they sell at quite reasonable prices. In any case, this may also help http://www.impresedili.it/categorie/prezzariGood luck with your endeavours!

Every region has a prezzario, a book which lists every job and every job component and their cost.  Sop you can discover how much it will cost to tile a floor in stone or in ceramic, how much it costs to take off old palster, and replaster etc.  You ocan find the prezzario online depending on the region or at a builders merchants or sometimes a bookshop.  They come out annually.  Any estimate given by a building company must be based on this prezzario - with subsequent discounts.