the cheapest way i could see you being able to do it yourself would be to cover the old asbestos with 3/4inch osb boards screwed through the asbestos sheets to the under purlins.then cover it with self adhesive roofing felt which you could get from most roofing merchants,this way you wouldnt need to buy any specialised kind of tools ,gas torch etc.it all depends on what sort of finnish and how long term you want it to be,you could always try a fibreglass based paint called acropol around £60 for a 10ltr tub which is effective but looks a bit messy in my opinion,but as they say you get what you pay for.
jimbobly, November 2012