If you have wood decking, there are several common deck problems that you might encounter. For example, your natural wood boards may fade over time due to things like sunlight, weather, and debris. On top of that, some types of wood decking can rot, grow mold, and attract destructive pests—including termites, carpenter ants, and woodpeckers.

Yes, it is generally a very good idea to seal your deck after pressure washing. Power washing removes not only dirt and debris but also a thin layer of wood, leaving the surface exposed and more susceptible to weathering. Sealing is almost always needed after this process. After a general cleaning, sealing isn't automatically necessary if the existing sealant is still intact. You can test the surface by placing a few drops of water on it. If the water beads up, the sealant is working. If it soaks into the wood, it's time to apply a new sealant. If it has been a few years, it's wise to remove the old sealant, wash the deck, and reseal for maximum protection.

The best paint for an older deck depends on the material and whether or not your deck already has a coat of paint. Generally, if your deck already has paint on it, you should choose the same type of paint when repainting the deck. For example, if an old deck has oil-based paint on it, stick with oil; if your deck has water-based paint, choose water-based paint. 

It’s important to make sure the wood on a new deck is properly seasoned. Seasoning a deck is simple: Once you build it (or have a pro do so), just leave it alone so it can acclimate to the environment. If you don’t give the deck proper seasoning time before staining, the stain can lock in any lingering moisture and cause mold, rot, and other moisture issues down the road. Give the wood at least four to eight weeks to season before you stain.