I live in Dublin, we bought a house 4 years ago and renovated the house, incorporating the conversion of the garage into the granny flat as part of the mortgage. We had to put in a separate internal porch and keep it as part of the main house because the local council would not allow us put a second door out front anyhow due to planning restrictions. Our flat is 22m2 and has a bathroom at the back, a single bedroom and then a kitchen living area in front. We are getting 1000 a month under Rent a Room and have rented to a lovely person who is on the Hap scheme. Bills are included. It is small but perfect for one person. It meets all requirements as it was examined by Inspex. Be aware of making sure that it is fully firesafe and meets the requirements as laid out https://www.gov.ie/en/publication/3...accommodation/#what-the-minimum-standards-are as you maybe inspected depending on where you live. We were. I would recommend doing your job OP as you're getting income for yourself and removing one person from a possible situation of homelessness. We do eventually intend on either letting the children live there when they're older or letting one of their actual grannies or grandfathers live there if ever needed.