I am buying a house with a huge deck with two staircases. The wood is stained and looks decent, but you can see some mold growth underneath and just needs some general TLC. The house has not been lived in for over a year. Looking for some simple advice. Thinking I should just spray whole deck with a cleaner then respray with a sealer? There are a lot of loose rail pieces along the edges. I imagine I should re-tighten all first then clean and spray or does it not matter? Also, recommendations on products? Any help is appreciated!