Water Proofing

Every pop-up can have different canvas. Older pop-ups used real canvas which has a tendency to rot if not maintained. Around the mid-90's most popups started using Sunbrella. That is canvas like material that has been treated with a water resistant coating. Sunbrealla feels more plastic like vs the rough texture of real canvas. 

Having Sunbrella canvas means you really don't have to water-proof. The seams may need some attention occasionally, but in all the years we've owned our pop up we've never had leaks in the canvas. One seam did develop a slight leak and was treated with seam sealer.

Condensation can be an issue though. After a cool night and having several bodies inside breathing away you may notice moisture on the bunk ceilings. If you keep a window slightly open or run a fan that can minimize the moisture buildup. 

I see recommendations for the water-proofing spray that Bass Pro Shops carry as one of the best around. Since I've never used it don't take my word for it, but again I see it suggested often.

Remember even with Sunbrella the bunk end windows are canvas, and may need some attention. We've never had an issue with ours, never water proofed them.