So I purchased the Noah's Tarp 16 for its basecamp size and lightness. I have little crawlers and toddlers, so it was supposed to be a wind resistant, waterproof canopy, to give the kids room to play if we were rained out. I liked that it was the thicker 70 denier and polyester for better durability, but knew going into it that it was pu coated and not silicon impregnated.

I took it out and found that it was not completely waterproof. It misted through under moderate rain. It wasn't a deal breaker, but was more than disappointing. I know there are pu aerisol sprays, but have only felt they restored a fabric back to factory standards, not really improving on them.

I am aware of ways to increase the waterproof coating of silnylon with silicon caulk cut with mineral spirits. I undertand that such a coating is much thicker and stiffer than factory. I was also under the impression that this method doesn't work over a pu coating. Can anyone here verify this? Is there a diy method for making my pu coating truly waterproof? I don't mind if it adds to the weight of the tarp or makes it more stiff. Waterproofness is the key.

The tarp worked great otherwise.