Seam Grip + TF Tent Fabric Sealant

So far it does a good job of keeping my tent dry, but you better buy two bottles of you're waterproofing both the floor and the rain fly. Also, the dispenser is terrible for a large project. Get a sponge brush like you'd use for staining wood, cut the bottle open, and dump it into a jar. Project will go a lot faster and easier that way.