You can use latex or acrylic paint outdoors. Although acrylic paint tends to last longer outside, it also costs more, so if you’re painting the outside of your house, for instance, latex paint is often a go-to option. However, acrylic will be your best choice if you want to spend some extra money for added durability.

It’s necessary for paint to completely dry before exposure to rain, and that drying time varies by the type of paint used. Oil-based paint takes 6 to 8 hours to dry on average, meaning that’s the minimum time needed between the last brush stroke and the first raindrop. Latex paint dries faster at around 1 hour, and acrylic paint is even quicker, usually drying in about 30 minutes. If rain is in the forecast, check the paint manufacturer's details before laying on a new coat. 

In most cases, sanding an old deck before staining it is necessary to achieve a decent finish. If your old deck has a relatively new stain finish on it and you're only doing touch-ups, you can generally skip the sanding part. However, if your goal is to make the deck look and function better, sanding first is a must. 

Liquid rubber is great for waterproofing, but it can damage your deck if it’s not applied correctly. First, it can trap moisture in the wood if the deck isn’t completely dry before application.  Second, applying it too thickly can create a heavy, rubbery surface layer that peels and cracks under fluctuating temperatures. For the best results, ensure the wood is completely dry before application, and apply the liquid rubber in thin, even coats. A quick inspection every now and then will help you catch any issues early, keeping your deck protected and looking its best.