It entirely depends on your roof height, most modern houses do not have the height for a loft conversion. Therefore you have to start there as there are building regs which dictate minimum height requirements. Thus before you go down the route of ideas, find out how high the pitch is, if you need to raise the roof, you're into big bucks!. Then you need to look at the layout of the floor beneath and decide where stairs can go, clearly you need to get into the roof space at the highest point, usually a gable end. If it's possible to gain access with a staircase, this will then dictate the layout in the loft. Thus, you need to post a lot of plans and measurements before anybody can really help you x

Personally I think you need to check the planners view on making the existing loft bigger with either dormers or changing the hipped roof. If budget is an issue I suspect you won’t find moving the stairs to the loft cost effective. But you can likely make the landing lighter by addition a velux at the very top of the stairs. To gain additional accommodation the loft seems like the most cost effective solution but you could also extend over the sun terrace.

Hi there, if you want to maximise space, you can build right up to the party wall boundary. Are you having brick walls or tiles? If you are having tiles, you need to make sure that the builders build the structure so that there is enough space for the tiles and the edge of the tiles remain on or just slightly within the party wall. If not, it could be very costly to put it right. When your neighbours decided to build their loft, they can 'link' their dormer to yours if you don't mind the neighbours doing that, otherwise they would have to move their dormer wall in about min 60cm to allow for someone to tile the side of the their dormer. We are also in a terrace, one neighbour built their dormer years ago but it remained well within the party wall boundary, however if we wanted to build our dormer completely separate with tiling all around, we would have had to come in a lot which meant a smaller loft, so in the end we built the shell up to the boundary ( without tiling in the 'gap' between our dormer and neighbour's dormer, neighbours dormer side with tiles remain untouched ), there is probably about 30cm gap between the two lofts, then the gap is filled with insulation, the roofs are joined together and the gap on the face of the two dormers are tiled. Sorry, sounds a bit complicated, basically nothing really happens with the orginal neighbour's loft ( which will be you ), the neighbour doing the new loft will just attached their loft roof and dormer face to yours.

i used glulam before which is similar to the one you talking about but im afraid most of the structure engineers and inspectors are not happy with more likely just because the system is new and they are not too sure about the result in a next 20 years.