Changing layout to gain an additional bedroom - question...

[Onz]

Hi, we have an old cottage that has 2 double bedrooms similar in size on the first floor and in one of the bedrooms there is a door with a staircase up to the attic that is all fully boarded out, plasterboard on the walls ready for plastering, lights, sockets etc. and a window on the gable end. Enough space and head height to use as an additional bedroom.

I'd like to put a stud wall up in the bedroom that has the door to the stairs to give access from the first floor landing to said door without having to go through the bedroom, this would then give us 3 separate bedrooms to use. Obviously we'd lose some space from the bedroom but it could still be used as a spare double room.

How do I find out where we stand should we wish to sell in the future. Would we just list it as a three bed or is there something we have to do formally to record it as changing from a 2 bed to a 3 bed? I wasn't sure who was best to ask - architect, building control(?), solicitor?

Highly accurate (!) sketch below showing layout as it stands and proposed below that.



Any thoughts welcome.

[ndg]

To be legal the attic needs to be inspect and signed off by building control. This will include the structure (floor/roof), insulation and fire escape - the doors to the stairwell will need to be fire doors for example.

Itr would be best to talk to a builder, architect or architectural technician for help.