Scrim for asphalt split - what's it made of..?

[j1mm1nycr1cket]

Allo. I've got a few cracks in the asphalt covering my garage roof. I'm going to give them a coat or two of cromapol / acrypol / evercryl - whichever I can get from the local Roofshop.
I read that it's wise to use a scrim over the split parts. My question is: what is roofing scrim made of and is it different from plasterboard scrim?
I just wonder because roofing scrim seems very expensive whereas plasterboard scrim is cheap, so I guess there is a difference...
The Acrypol branded stuff *looks* like it might be made of some very lightweight metal/aluminium or something which would make sense as they say it can support Acrypol over holes in roof sheets.
What can I use that doesn't cost 70-80 quid per roll
Thanks

 

[Xenon]

Use Cromapol, it has the fibre reinforcement already in it.

 

[cotswoldbuilders]

Glass fibre matting.

 

[catlad]

Go ahead and use plaster board scrim it will be fine for small cracks.

 

[j1mm1nycr1cket]

Thanks a lot for the advice.