Hi and thanks for the question.
There’s no one right answer to this: it depends on the scale of the room, the look and feel that you’re trying to achieve and the lighting requirements. You would light the task areas of a kitchen differently to a living room for example. It might be useful to lay out some design principles though.
Design principles for lighting rooms with pitched ceilings
We would strongly advise against recessing downlights in to your ceiling insulation; this isn’t good for either the downlights or the insulation.
Look at all your available fixing points, not just the ceiling but also walls, floors, furniture or joinery. The best solution may well involve using several or all of these.
Ceiling mounted fittings may include suspended fittings (not just pendants, but also potentially suspended tracks), or surface mounted spots
Wall mounted options may include tensioned tracks, sleek architectural light fittings, more decorative wall lights, and even picture lights.
The floor can provide a fixing point for both ground recessed fittings (eg; uplights or linear wall washes) and sockets for lamps (particularly useful around central seating in large rooms).
Joinery and furniture offer a wealth of opportunities for lighting, eg; using it as a mounting point from which to wash light upwards, or having lighting within it, or using it as a base from which to take light downwards.
The scale of this barn is unusual. Most of us don’t have to consider lighting 8m high ceilings but the principles are the same. Have a look at the case study for lighting this barn for more detail.