From an experienced pastor:

I’ve been invited to bless new homes on several occasions over the years – mostly by people from the Indian subcontinent. I normally take an extemporaneous approach.

Over the years I have also been involved in a few “spiritual cleansings” of homes in which there have been disturbances. It’s been encouraging to receive reports from the home owners of peace following the time of prayer.

On the subject of Irish blessings, here are two I like. I don’t know the author of either.

IN THIS IRISH HOME (I used this as a benediction on Mothers Day)

May these walls be filled with laughter,

may it reach from floor to rafter.

May the roof keep out the rain,

may sunshine warm each windowpane,

And may the door be open wide

to let the Good Lord’s love inside.

More general one…

God be within you, to strengthen you;

over and around you to ward off your spiritual foes on every side,

under you to uphold you in your goings,

behind you to guard you from the assaults of the past,

before you to lead you on.

The Lord keep your thoughts,

direct your steps,

conform you to Jesus Christ,

now and always. Amen.