I'm a Dubliner but live and work in Belfast where I rent a place and am paid & taxed in UK. I have for a couple of years rented out my house in Dublin under the rent-a-room scheme since i was back and forth a bit.
If, as seems to be the case, the Dublin property is not your principal private residence then you should not be availing of the rent a room scheme and doing so may constitute tax evasion.
I want to switch to the full house rental as non-resident.
What do you mean by "switch" in this context?
I heard you had to own your house for x years (maybe 5 ?) to NOT be liable for paying stamp duty of purchase price
Where a property originally purchased as an owner occupier is rented out within five years of purchase (other than under the rent a room scheme where this legitimately applies) then a clawback of stamp duty applies.
If I was you I'd get professional advice on my tax/residency situation and the legitimacy or otherwise of having availaed of the rent a room scheme to date.