We had a load of rigid PIR insulation of various thicknesses left over from our work so I laid that directly onto the joists in the parts of the loft I would have boarded. Fluffy knauff in the eves and everywhere else. You’d have to do the maths to see if it’s cheaper or the same as fluff, boards, loft legs and your time. It’s certainly quicker.
I actually have a decent amount of PIR that I started to use for insulating in between the joists in the basement. I’ve discovered that’s quite difficult when the joists are old and uneven. Maybe it’s best to use that for the loft instead!
Reckon your plan makes sense.
We had a load of rigid PIR insulation of various thicknesses left over from our work so I laid that directly onto the joists in the parts of the loft I would have boarded. Fluffy knauff in the eves and everywhere else. You’d have to do the maths to see if it’s cheaper or the same as fluff, boards, loft legs and your time. It’s certainly quicker.