Had a porous asbestos roof, no cracks or damage. Thought of renewing the roof but was put off by the cost of removal and disposal of the asbestos. Saw an advert for Grey 5kg Liquid Roof Seal Paint - Felt-Asphalt-Asbestos-shed Roof Repair Liquid, and thought I'd give it a try. Followed the instructions and painted the roof (I also used composite flashing tape over the joints on the corrugated asbestos sheets before applying the paint). It rained the following night, opened the shed door. I was amazed no leaks or dampness anywhere. I then bought a second 5kg can and went over the first coat so should be right for quite a while now. Highly recommended, easy to apply and best of all, really works.