I'm replacing the insulation on my sleeping loft (where there is very low ceiling and slanted roof). I plan to use SPU boards instead of the mineral wool currently there. It gives me 3-4 cm extra, which may sound small, but when it's very cramped it can feel like a lot 
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Currently, there are 30x65 battens, quite close together, between the rafters with a simple plasterboard screwed onto them. My hope is that with the SPU insulation, I can have thinner insulation, skip the battens, and screw the plasterboard directly onto the rafters.
Is this possible? There is 100 cm between the rafters and the slanted roof is somewhat less than 45 degrees. What I am wondering is if it's simply too far between the rafters and if that's the case, is it possible to place battens between (not on) the rafters (attached with L-brackets, for example) to give the plasterboard extra support?
Are there different types of plasterboard and if so is there a specific type that is better suited for slanted roofs?
.Currently, there are 30x65 battens, quite close together, between the rafters with a simple plasterboard screwed onto them. My hope is that with the SPU insulation, I can have thinner insulation, skip the battens, and screw the plasterboard directly onto the rafters.
Is this possible? There is 100 cm between the rafters and the slanted roof is somewhat less than 45 degrees. What I am wondering is if it's simply too far between the rafters and if that's the case, is it possible to place battens between (not on) the rafters (attached with L-brackets, for example) to give the plasterboard extra support?
Are there different types of plasterboard and if so is there a specific type that is better suited for slanted roofs?