Depending on the property (and the budget), both options have their merits. A big loft space can be more easily converted to a room but often the structure or space isn't sufficient and an dormer or extension is needed. This can offer a whole new floor to the building and with some imagination you can transform the property completely. www.pwjarchitects.com

You're right that if your '90s semi has the ‘W’ shaped supports in the loft, then it’s a truss roof. These can be trickier to convert than older lofts with traditional cut roofs, but it’s definitely possible with the right structural work. When it comes to the staircase, it’s typically placed above your existing stairs to conserve space and maintain a well-flowing layout. If that doesn't quite work with your layout, it may need to be adjusted slightly to fit into the second bedroom. A good loft designer or builder will be able to advise based on your measurements and ceiling height. They’ll also ensure the stairs comply with building regulations, particularly regarding headroom. For the en-suite, placing it above your existing bathroom is often the easiest option, especially for plumbing. It means you can tap into the existing soil pipe and water supplies, which keeps things simpler and more cost-effective. That said, if the layout makes more sense to put the bathroom elsewhere, it can be done, just with a bit more work. The rear dormer sounds like a great idea. It’ll give you much more usable headroom and open up the space properly, especially if you're looking to fit both a bedroom and an en-suite. That’s what often makes the difference in terms of value. For a two-bedroom home, adding a third bedroom and bathroom upstairs can significantly enhance the feel and function of the house, especially if space downstairs is limited. It’s worth having someone take a proper look and sketch out a few floorplan options. That’ll give you a much clearer picture of what fits and whether it’s worth going ahead. However, yes, it’s totally doable, and many homes like yours have been successfully converted with great results. Hope that helps. Happy to share more if you need. Tom LoftCompare

I have a barn conversion. It's a really personal decision. Some of my home is open plan with ceilings of 5m but where I have rooms downstairs and upstairs off the main space the ceiling is 2.3m and I hate it. They are too low. They are large rooms of about 25 sq m so not small but the lack of ceiling height is oppressive to me. I'm not tall but very claustrophobic. It's personal. No one can really advise you. It might not bother you at all. Try and visit some houses with low ceilings to see how you feel first before spending a fortune on a loft conversion.

You don’t have to close off the second space unless you want it to count as a formal bedroom on the plans or for Building Control to treat it as a separate habitable room. Building Control mainly cares about safe escape routes, fire protection, and the staircase layout. As long as the main bedroom space is properly enclosed where required for fire safety, the rest of the loft can stay open if it is being used as a landing, storage area, or general open space. Many people with smaller houses keep part of the loft open to avoid awkward stair designs or losing headroom. The key thing is that the enclosed bedroom must meet the rules on fire doors, insulation, and escape windows. The open area usually just has to meet the general structural and insulation requirements. Your builder or architect can confirm the exact layout, but you usually do not have to redesign everything just to close off that second space unless you specifically want two separate rooms.