Should I parallel the tense used in the question?

I meet someone I haven't seen in years and they ask me what I have been doing over the past years. One of the things I have been doing is building a house with my husband. The house is finished.

How do I answer their question: "I have been building a house", paralleling the tense used in the question

or "I have built a house" because the process of building has come to an end?