You have two very different and distinct issues running through your question.  First you claim that the property was built by you prior to marriage - which would mean that it was separate property - BUT you placed her name on the property as a joint owner.  So there you have it: marital property.  So now, the property has to be included in what ever settlement agreement you come to with regard to joint assets.  Now two, iIf you and she do decide that she wishes to relinquish her rights to the house then I would NOT consider drawing up any document your self and I would not consider her signing it unless and until she is advised by an attorney on the matter.  Otherwise I think that you could ge in to a heap of problems later on.