found a amall crack in my garage asbestos roof now leaking when raining

Flexacryl , Cromapol ,Acrypol all will do the job simple brush on application available any roofing merchants or even ebay Would be interested to know what cement based waterproofing material Diamond Construction is on about! Have just done 600m2 coating asbestos roof on a factory approved by Cromapol not sure what they would think of their product being called a bodge

All the products Tradecall mentions will do the job, also you can get some flash band, clean area (carefully, wear dust mask, asbestos )apply primer, stick on flash band, heat it gently with hot air gun and firm in place.

you can buy cement based equivalent for same price as above materials and replace it easy do it proper dont bodge it like they would