I built it all from scratch, 75mm X 50mm Stud work, wrapped in building paper then Laplog Cladding ( so looks like a log cabin ), Pan tile roof sheets ( looks like a pan tiled roof, they now use these on static caravans ), then I plasterboarded the insides, Concrete base with OSB floorboard for the floor covered in LVT flooring, a 2nd hand Composite door and Frame, 3 X small UPVC windows ( they were sample window that the sales team from a local window firm had in the sales dept, they changed suppliers so I grabbed 6 of them

) all with as much insulation as I could justify, built a media wall for the TV and games consoles, put my old 4 seater sofa in it, when the wife allows me I will build a small bar in the corner ( but I need to get brownie points by redoing the ensuite 1st ) its a very nice space even if I say so myself
Ive built a 3 X 4 M shed, this 5 X 3 M mancave / place for kids to go with mates and make as much noise as they want , and Ive got enough Cladding and roof material to build a 4 X 3 M building ( this cant be attached to the mancave, as building regs state the max size is 15M2, so will have a small gap between ) which might be a home gym or a small salon for the wife ( if she wants it ) Im currently 22K in on costs, as for the man hours its taken me, its far too long, would I do it all again, not sure to be honest, but it was one of the clauses that I agreed to with my youngest ( who didnt want to move ) when we moved, so ive kept my word, shame its maybe 2 years too late for her to really enjoy