Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
Roof is definitely not waterproof. I can see it dissolving after a few weeks of being in the sun. It is like a very thin enviro material. I will need to spend more money to apply a better seal. Overpriced. Wish I had more time to purchase something local.