Loft roof insulation

[meddyliol]

Hi, as a newby to this forum this question might have already been answered, if so I'm sorry.
I need to insulate the spaces between the roof joists. I have rolls of insulation material from B&Q and this is easy to fit. What is the best and hopefully cheapest way of stopping the stuff from falling out? I could fit sheets of plasterboard over the beams but is there an easier way?

Thanks

Brian

 

[Stupidmia]

My hose didn't have insulation between the joists (insulation was attached to the underside of the roof) this qualified me for one of those energy efficiency grant schemes. I tcost me £220 for roof and cavity insulation

The insulation depth is about 10", which apparently is the recommended standard....however, if this was enclosed by putting boards down, it will flatten the insulation and I imagine this will affect the insulating properties of the material due to the reduction in entrapped air pockets.

The stuff comes in rolls and is laid in lengths, so when you say it will fall out....I don't understand what you quite mean?