Of course, one question that might come to mind when considering a guardrail is "why not a wall?" This example illustrates that a wall can double as a guardrail — in this case in the same central position as the previous stair — while the stair is still relatively open. Here that effect is aided by open risers.
This stair combines a translucent glass wall with wood guardrails; the latter matches the steps fairly well and has a nice abstract quality from the simple construction.
Solid guardrails, be they wood or metal, can also be made porous through cuts. This curving stair — easily one of the most elegant on Houzz — is a beautiful design that bridges art nouveau and modern/contemporary design. The flower-like pattern cut in the steel varies from solid to areas with spindly lines, but the overall effect is of something solid and heavy. No doubt this effect is related to the material, the color, and the way the steel plates extend beyond the steps.
Of course, guardrails don't have to be completely solid or transparent. This stair and hallway feature a partial-height wall capped by a steel-bar picket railing with a continuous wood handrail on top. This design minimizes the extent of the steel railings, giving the guardrail a little more weight, keeping in line with the rest of the house.
This guardrail uses perforated steel plates to give a gauzy translucency to the inside of the stair. The effect works with the area's materials and design: wood floors and walls, and perforated metal light fixtures suspended from thick rope.
Another stair with perforated steel guardrails illustrates one thing that can happen regardless of material: The guardrail can be used to fill in the zone from stringer to stringer. This piece in the foreground acts basically like a wall, but it is clearly part of the stair, both in terms of design and construction.
More transparent than perforated plates are pickets, vertical railings usually capped by handrails. This stair shows that the steel bars are actually L-shaped pieces that also support the wood treads.
A closer look at the same stair reveals how from certain angles the guardrail can appear solid, owing to the size and shape of the pickets. View them head-on and they are nearly transparent.
This guardrail features round pickets that extend from the steel steps to the ceiling above and the floor below.
A few of the following examples feature rods and cables oriented horizontally rather than vertically. This stair combines the vertical and the horizontal by using a woven mesh. In this design the mesh is held within a frame that "floats" within another frame connecting the stair to the steel stringers. It is a detail-intensive design that some may see as busy, but it is fitting with the loft-like space marked by exposed steel joists.
A fairly popular contemporary solution for guardrails is to use rods or cable that follows the slope of the stair. In comparison to vertical pickets, this approach minimizes the number of pieces that must interact with the stair treads. Here we can see that three vertical supports are mounted to the stair in each run. These pieces then receive the rods that follow the slope.
A variation on the horizontal/sloping rods, or in this case cables, is the angle of the supports. In the previous example they are vertical, but here they are perpendicular to the cables. The wood infill piece at the bottom transitions between this angle and the vertical pickets you usually find.
Here is another stair with cables in tension between steel supports. The design of this stair is simple, consisting of two materials: wood for the treads and handrails; steel for the stringers and guardrail/handrail supports. Note the attachment of the paired vertical supports to the face of the stringers.
Here is another fairly simple cable stair/guardrail with frosted glass treads, steel stringers and guardrail/handrail supports, and a wood handrail. The last picks up on the wood mullions and actually steals the show; note how the handrail bends and curves to transition from run to run.
Cables can also be used vertically, as this stunning example shows. Here the cables, which extend to the ceiling above, help support treads that are otherwise cantilevered from the wall. Elsewhere glass is used for guardrails, making this construction in cable stand out even more.
And the last example brings us to the most transparent type of guardrail: clear glass. This stair uses pieces that are held in place by the slender steel handrail supports. For safety reasons it is always good to use tempered glass, ideally with a laminate to hold the glass in place should it break.
A number of stairs on Houzz use glass as full walls at stairs. Here the glass extends from floor to floor; note the detail where the glass is pinned to the edge of the floor.
While the previous example positioned a full wall of glass opposite a solid wall, this stair is situated next to a small courtyard. Therefore the glass guardrail in the foreground helps to bring daylight from outside to inside.