Build attached extension with self contained unit

Grawns

This would be accessible from the kitchen and from the back of the garage. 40 square metres to include kitchen living room, bedroom, bathroom and shared foyer. I'm very confused about planning permission as it seems if I build it I don't need planning permission but if I say I'm building it to future proof as inlaws getting old and I may rent it in the meantime I won't get planning. It's to be attached and to the back of the new build house and would be to code including solar panels and A rating. After reading everything I can find I'm of a mind to build it and not look for planning. It would be easy to revert back to the main house and I love the idea anyway as the shared foyer would be a bootroom next to a wet room for the muddy dog.

Am I missing something? I don't need permission and I do at the same time? I'm just mulling here!

Grawns

The door top left connects to kitchen, the door top right to car port. Have tweaked original concept

coolbeans

Looks OK but I dont see a carport. Regardless, re planning you'll likely need to include an internal link to the main house to satisfy the planning authority that that you're not building another dwelling that could be lived in independently.

County development plans will have policies for just this scenario. The policies can generally be found using the terms 'family flat' or less likely 'granny flat'.

If you don't wasn't to go for planning it's good to know what they do require all the same.

Claw Hammer

You are subdividing a planning unit. You ned planning permission. If you have a family need the council will allow it of you demonstrate a current need and they will impose a condition that you convert it back to single dwelling use when the family need is no longer present.

Grawns

Thanks for your comments guys.