I know this is an old thread but I just saw your reply. I didn't cover the supports are all but 2 of them are treated 4X4's. Once the 2- 2x4's rott out I will replace them with 4X4's which I should of done in the first place. I did silicon all the cracks. I'll see how well this holds together and go from there.
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John Light
JPLReptiles@gmail.com
(954) 903-8061