We blessed the rooms we use most and rooms of significance from my childhood in all three houses. In the rooms where I have bad childhood memories we said the prayer:
"Let the mighty power of the Holy God be present in this place to banish from it every unclean spirit, to cleanse it from every residue of evil, and to make it a secure habitation for those who dwell in it; in the Name of Jesus Christ our Lord, Amen."
The priest seemed to really understand what we were doing and prayed for past, present, and future inhabitants of the house.
My kids were uncertain about the idea beforehand, but when we blessed the rooms they use they joined us. It seemed to mean something to them.
It meant very much to me. The electricity went out sometime while we were doing the houseblessing and I joked it was that powerful (it came on again about half an hour later).
Then the sun came out and we went to the sandbars in Nantucket Sound.