Steps/cost to increase bedroom size

[Therandomdude]

Hi, I recently bought a house and although the family is happy the 3rd bedroom is quite small and would like to do a minor extension. I've noticed that lot of the houses in our street share the same floorplan and had the same extension done as the one I'd like to do.
Changing bedroom 3 from the first image into the one from the second one.
The thing is I have no clue on how much money I would have to start saving for the work, what steps I would have to follow, or if it would require permission and that kind of stuff. Any insight would be appreciated.

Honestly your best bet is to get a couple of builders round and ask for quotes. A lot depends on whether that wall you want to move is a supporting wall (holding up the roof) or not.

Why not ask the neighbours who they used and were they happy with them? Then you can approach those builders for quotes. You could ask the neighbours what it cost though obviously prices will have changed.

Do you mean extending the bedroom out or just moving an internal wall?

Moving the bedroom door and making good the plastering should be less that £1000
A double height extension is more like £100,000 nowdays. Could be more if you are in London or the south East.
Looks like they have just had the door moved. You don't need planning permission for that and just want a recommendation for a good builder although carpenter might be able to do it if they know a plasterer and you don't mind decorating after.

It looks like moving a non structural wall so shouldn’t cost too much at all. Find some reputable builders and get some quotes. A full extension is going to be £100k or more but that doesn’t look to be what you are thinking

Seems simple enough. Get some quotes.
Consider using a sliding door to that small bedroom, opposite the doorway to bedroom two. Think about how best to give you more room and better outcomes to fit your desired furniture.

Question..
Why are you moving the bedroom doorway of bedroom one?
Could the cupboard door in the passage open into someone's face when they are walking out of bedroom one?
Will furniture be more difficult to move up and down the stairs?

We’ve been quoted £120,000 for a one-storey 10x4m2 extension in outer London. Best bet is to get someone (several people) in for quotes.

it isn't quite clear what you are planning. I think on the second floor plan, they have taken down the internal wall between bed3 and the landing and put up a new wall that incorporates the little bit of corridor into bed3. this would certainly make bed3 larger and nicer.

unless this is a listed building, you don't need planning permission. It might cost £1K for the building work plus redecorating bed3 afterwards (paint / new floor if needed).

Yes, that is exactly it. Thank you, I do hope it's around that price range.

Thanks everyone, I'm going to try and learn a bit more about house improvements (all a bit confusing for me 😓) and get some quotes.

The good news is that if your neighbours have done the same extension, there's a precedent, which helps with both planning and finding builders who know the build type.
Steps in rough order: check whether it falls under permitted development (your council's planning portal will show what's been approved on your street, which is a useful shortcut). If neighbours did it without planning permission, yours likely qualifies too. Then get a structural engineer and architect involved to draw it up, followed by building control and contractor quotes.
Cost depends hugely on what's below. If you're building over an existing ground floor extension, the structure is already there and you're looking at a simpler job. If you need new foundations and ground floor structure to support it, costs rise significantly. For a single bedroom extension in most parts of the country, budget somewhere in the region of £30-50k as a starting point, but get proper quotes against drawings.
The fact your neighbours have done it is your biggest advantage. Ask them what it cost and who did the work.

Did you look at the plan at all. She literally wants to remove an internal wall and relocate the doorway.

no need for planning at all

Fair point. I jumped ahead without looking closely enough at the plans. If it's just relocating the internal wall and doorway as others have said, this is a much simpler job. Get a builder to confirm the wall isn't loadbearing, and you're looking at a fraction of those figures. Good luck with it.