Hi A couple of thoughts on your options; Loft conversions can be a great way to increase habitable space but they can sometimes be mistaken as a cheaper option -there is usually a lot of work involved in doing it properly. Also a loft conversion can be quite invasive, it is often easy to overlook the amount of space required at first floor level to accommodate the staircase to the next floor - if space is tight, sometimes this can result in a double room becoming a single or even losing a single room. Adding a third floor to the house will mean that you will have to replace all of the doors to rooms that open onto the hall and landing with fire doors. It is worth remembering that replacing the conservatory with an extension might require planning. The local planning authority might be prepared to discuss the requirement with you, but you design consultant will be able to advise. Have you tried the Find A Pro section of Houzz? its worth a look to see if there are any consultants in your area. If it looks like they do house extension work its worth messaging them - even if they don't have a photo of a project similar to yours, they may well undertake such commission but didn't photograph it. Architects always welcome new enquires, if they cant help they might be able to put you on the right tracks to someone who can.

Many thanks Owl for the feedback. I understand what you are saying regarding constraints and the loft stair is something that was proposed by our architect and that we explored in detail. However, it is not something relevant for our family situation with our children and their specific needs; and in addition, it was making the rooms at the end of the corridor (on the left side) either too big (if merged into 1) or (if keep as 2 bedrooms as they are) too small. The middle bedroom was becoming very small and the 2 rooms above where not that much bigger due to the shape of the roof. Our architect did draw plan for this option but after review, it was not the right thing for us. I am keen to know, with our current constraints, you or any one else has some comments :) it would be really appreciate. Many thanks

We used to have something similar - we’re in a Victorian terrace that had a very old attic conversion when we bought it. The stairs were off the middle bedroom - the landing wasn’t altered in any way. The door to the middle bedroom was taken off (architrave remained in tact) - you walked through this gap and turned immediately 90 degrees to go up the stairs (the stairs ran along the bedroom wall). A new doorway was built immediately in front of the old one to preserve the bedroom (you wouldn’t need that in your plan!) The bedroom is quite big, so still felt quite spacious. My sons bed (an Ikea mid height thing) used to go under the stairs quite comfortably. A few years ago, we moved the stairs to come off the landing. The reason we did this was because the stairs off the bedroom effectively ran up the middle of the house - it meant that the attic conversion was two rooms. By moving the staircase to the landing and running them above the main staircase, we now have a large attic master bedroom and en-suite. It’s a much more usable space.

I think you are right to have envisaged a stair newell post sitting completely on the landing. It looks like an error in measurement or manufacture to me. Your Architect will be the best person to help you come to an arrangement that is satifactory. Did you see the stair design before it was manufactured? Was there any prior discussion before manufacture of the exact finished width? It is possible that there was a communication error. Most important do you have anything in writing to confirm that the stair was going to be wider? Is there a stair width dimension on the Architect's drawing or was that detail left to the surveyor? You use the word "seem" which is an assumption.