Inspectors see any number of decks. Some are well built. In this wet climate, we like to see the structure built out of pressure treated lumber and concrete piers that isolate wood from soil. As the composite deckings get better looking, to look much like wood, they are becoming more common. Even though these materials are good, weather-resistant decking, many people who install the material do not follow the manufactureer's installation guidelines -- which are quite specific. The manufacturer's define where you can, or cannot, use the material and also the distance to centers (joist spacing)  is important and depends on the decking that is chosen.

The photo below was odd. The deck structure was well-built, and the centers were correct, but then they got into being speedy when installing the decking. You will notice that the butt-joints and all decking is held in place at joists with a single screw at the center. I checked that method, against the manufacturer's specifications and sure enough it is wrong. This manufacturer calls for two screws per joist, with the screws near the edges of the decking and going down with minimal slope. It is weird when someone does a good job, and then botches it up at the end. Maybe the homeowner had a builder do the structure and then did the decking himself on weekends. I have seen that sort of scenario, the idea being that nobody could mess it up once the structure was built. Unfortunately, that is wrong.

Thanks for dropping by.

Steven L. Smith

Bellingham home inspector