Good technical advice and support before and after purchase. The DIY videos are really helpful however they can lead one to believe this is easier than it actually is. Working on a flat roof with good access is relatively straight forward, working on the double pitch roof with limited access needs a lot of planning and even more patience! Although there is plenty of emphasis on keeping the resin, catalyst and buckets cool there is no mention of taking into consideration the temperatue of the roof you are applying the GRP to - I learnt that you need a reduced amount of cat as the roof got hotter. Please take notice of the advice when mixing quantities of topcoat as yiu need to be thorough when applying thep roduct and this takes time which leads to the product "going off". All in all would i do it again - yes, would I recommend CRS - yes.