Well, I still have a problem with the roof on my Harbor Freight Portable Garage. Even after putting a support slat across the rafters I still have rainwater pooling up. The single slat just moved the sag up towards the peak of the roof. I am going to add two more slats and see how that works out. I’ll keep you posted on that. Oh, and even where it doesn’t sag, the condensation on the roof material will drip a good bit on the inside so this setup can’t be called completely waterproof. If you store something inside that must be kept completely dry you will have to cover it with some additional material. I’ll keep you posted.