Below is a list of Decking Screws manufacturers from San Marcos, California. Decking screws are long, thin screws that are specifically made for outdoor use in all weather conditions. They are usually used to join and secure wood boards together, and they can be driven into wood easily. Decking screws are so named because they are frequently used to connect the wooden joists of outdoor decks. They are able to be countersunk; countersinking is when a screw lays smooth against the surface of the material it is securing, which prevents things from becoming caught on the screw as they move over it.