Most modern railing systems offer a surface-mount post option. This has revolutionized railing installation and deck framing. Mounting the posts above the frame and decking means that deck framing won't need to work around inset 4x4 posts, and outside-mount 4x4s won't need to be notched or carriage-bolted.

Surface-mount posts can usually be installed with a star-head lag screw through the post base, into the deck framing beneath it. Most deck beams or rims are at least 2 layers or 2-ply, but a third layer of framing may need to be added, which we call post blocking.

Top rails are the horizontal beams that are used with almost all railing systems for a solid barrier, and is often used to mount the top end of balusters or braces.

Some railing systems like Ultralox and Impressions Express have both a structural top rail and a decorative cover that snaps onto the top rail. These top rail covers can be ordered in different profiles, to give the railing a different appearance, depending on the desired style.

Bottom rails are used on most panels that have vertical balusters or cables, as a stable horizontal "beam" for the bottom end of the balusters to mount to. Some horizontal cable systems do not use a bottom rail, and it is replaced by a cable, since no balusters need to mount to it.

Though many railing systems use aluminum as the post and rail material, aluminum railing usually refers to a system that has aluminum balusters, top and bottom rails, and surface-mount posts.

Aluminum panel systems are often sold as boxed kits that require the balusters to be connected to the top and bottom rails. Fully assembled panels are also available, with the balusters already attached to the rails, so that they only need to be trimmed to length before installing.

A sort of crossover between baluster railing and horizontal cable railing, vertical cable railing is similar in price to horizontal cable, but has the advantage of being installed more like an aluminum panel. Due to the cables being vertical, climbing up the cables is less of a concern than if they were horizontal. Most vertical cable systems will also have intermittent vertical balusters to keep the tensioned cables from bending the top and bottom rails.

For a more industrial look than baluster or cable, it's worth taking a look at mesh rail. Mesh panels are mounted into channels on the posts and rails, keeping the panel in place and covering the cut ends of the wire.

Panels need to be trimmed to fit between posts, and stair panels will be cut to a parallelogram that fits in your stair panel opening.

On aluminum mesh systems, top rails and bottom rails mount to the posts like a standard aluminum panel rail would. With wood-frame systems like Wild Hog Rail, metal channels are usually screwed to the wood posts and rails to secure the mesh.

Privacy panels are a great way to enclose a hot tub area, provide a solid wind barrier, or keep your neighbors from witnessing your dinner conversation. A double-sided decking can be chosen to coordinate with the floorboards, or screens can be used to allow for more airflow.

Some privacy railings are tested and as stable as railing and can be used instead of standard railing panels, but this varies by brand. If privacy panels do not meet these testing requirements, they will need to be installed alongside the railing panels.

This photo shows Deckorators privacy panels installed on a deck that is less than 30" off the ground, which would not require a railing panel.

Some metal railing systems also offer fascia-mounted posts as an alternative to surface mount posts, mainly for practical purposes. Mounting a post to the outside face of the deck is useful for adding a few more inches to the deck area, as well as not needing to screw into the deck surface.

It's more crucial with rooftop decks or waterproof decking to make sure that there are as few penetration points in the decking as possible, and fascia-mounting can usually help the builder get around this.

Surface-mount post kits usually come assembled, with a removable cap and skirt. Some include covers for the screws instead of skirts, for a slim or industrial look. Mesh, vertical cable, and glass frame systems usually use the same posts as aluminum systems.

When working with horizontal cable railing, posts will have holes drilled in the posts to allow the cables or fittings to run through the post. These choices usually include corner, stair, inline, and end posts.

Composite railing requires a sleeve, skirt, cap, and some form of structural post to be ordered separately. The structural post would either be a wood 4x4, or a special surface mount post with a narrow base that fits inside the sleeve.