Property declaration in Spain

[shoestring]

My brother and sister in law live and work in Spain. They built a house last year here in Ireland as an investment for the future. The authorities in Spain look for people who are resident and paying tax there to declare any interests including abroad.

Does anyone know what document would suffice to provide proof of ownership of a house in Ireland to the Spanish authorities?

 

[bacchus]

I think the question should be asked to the Spanish authorities.