How to properly attach a deck to the home.
Here we see vinyl deck flashing with a short return down the face of the ledger joist (the first board attached to the home), the siding was cut and removed and the ledger attached directly to the house framing and sheathing. adhesive flashing was also placed behind the ledger and extends down and just over the next siding board so that any possible moisture penetration is routed outside the siding again. The vinyl flashing extends up under the door and the siding adjacent to it. You can also see how a small notch was cut into the outside joist so that the 3/8″ return on the vinyl flashing can extend down through it so no water can travel across the top of the joist.
It is important that the flashing either be vinyl, stainless steel or that Vycor deck protector either covers the pressure treated wood or is used in place of traditional flashing. Standard painted or galvanized flashing will rust away in short order.