I'm ordering a jungle hammock in the next few days. I does have a built in "roof" however, I'm told that it's primarily for sun protection, and not for rain.

I'm wondering, is it possible to waterproof the built in "roof"? Could a standard water repellent (like for boots, etc) work? or would I have to "paint on" thinned silicone?

What about sewing on a tarp over the existing?

Or, would the best result be to simply get a tarp to use over the existing one?