Step by Step...
WHETHER YOU'RE OVERSEEING a contractor's work or have time to do it yourself, here's how building a deck proceeds:
POST HOLES ARE DUG, with a shovel or post-hole digger, according to the specifications established by the local building department,which will inspect them after they are done.
CONCRETE IS THEN POURED for the footings - about 450 to 500 pounds for each hole. Footings can be built on 24 hours after they've been poured.
A HEAVY "LEDGER BOARD" - typically a 2-by-12 - is attached to the house with galvanized bolts or 40d nails. Joists will be attached to the ledger board using metal joist hangers. Four-by-4 or 6-by-6 posts that support the deck are anchored to the footings.
THE TWO-BY-12 JOISTS are attached from the ledger board to a crossbeam that has been attached to the posts. Most contractors use metal joist hangers to attach the joists, but some bolt the crossbeam to the posts so that the weight rests on the bolts.
THE FLOORING AND 4-by-4 RAIL POSTS are attached. On a wide deck, decking boards of varying lengths are used instead of a single length, to avoid having a seam down the middle.
RAILINGS ARE BUILT IN SECTIONS by attaching 2-by-2 balusters a few inches apart to 2-by-4 pre-cut cross rails, so that the balusters will be on the inside rather than the outside of the deck - they look better that way.
THE RAILINGS ARE ATTACHED to the rail posts, which are notched to accept the railings flush. Then the rail posts are cut to make them even with the railings. The railings are capped, often with a fairly wide board, often a 5/4-by-6.
STAIRS ARE BUILT. Options such as benches or lattice work are built at this time.
Deck Cleaning 101:
WHERE THE SUN DON'T SHINE
QUESTION: I have a composite deck, light gray in color, and, even though I clean it two times a year with a power washer, there still is this light green mold that appears under the railing and on the steps.
Do you have any suggestions for cleaning, and what type of cleaner/detergent do you suggest?
ANSWER: As you surmise, mildew forms where “the sun don’t shine,” even on “maintenance-free” composite decks.
Just to clarify: No manufacturer ever claims its products are maintenance-free. That’s just wishful thinking on the part of those who sell the products and the fed-up-with-deck-cleaning homeowners they sell to. 
CertainTeed, which manufactures Boardwalk composite decking, states : “All exterior building materials require some degree of maintenance and cleaning.”
(Just because you don’t have to repaint vinyl siding doesn’t mean the green coating on the shady side of the house shouldn’t be hit with a power washer regularly.)
