Monumental Stair Design Considerations

by Jonathan McGaha | September 1, 2014 12:00 am

Architects and designers love playing with metal. Our standard palette will be found all over our projects and will include curtainwalls, doors, windows, metal wall and roof panels, canopies, fittings, louvers, column and grille enclosures, decorative railings, bases, trims and reveals. Unique properties of metal, in both strength and durability, make it a material that cannot be easily replaced in many applications.

More ambitious designers will try to tackle exposed structural steel. This is often tricky as structural steel requires fire protection and is a material that is traditionally concealed. Perhaps a favorite item for any architect to design is the monumental stair. Often a showpiece of the most important interior space, monumental stairs combines exposed metal structure, decorative metal elements, along with infinite number of other material finishes. Designers will often incorporate metal with wood, stone, ceramic tiles, glass, precast concrete and terrazzo, and come up with a wild array of design solutions. While there are rules to stair design governing risers and threads, landings, railings and infill panels, the designer is still truly left free to experiment. The supporting structure may be left exposed or completely enclosed by finish materials. More adventurous designs usually leave the structure exposed.

While it is possible for some of the components to be made by companies specializing in decorative and custom railings, monumental stairs are usually fabricated by local ironworks. How the design is communicated to the ironworker becomes critical. The drawings must provide all details describing complex geometrical relationships, and account for all types of conditions. Quality of welded joints becomes critical. Clean hairline joints are preferred for all exposed connections. Prior to fabrication, a mockup will be constructed showing typical connections, and once approved will be used as a standard to which the final product will be judged against.

Metal railings require close attention of the designer. They can be made of posts or glass supported. Infill panels can be made of glass, or wire rope, or many other paneled materials. For any glass used in a monumental stair, it is highly recommended that laminated glass be used. In case of breakage, glass will not shower down on occupants below. It is also important to ease the edges of any exposed glass. Designer should be mindful of any sharp edges in general. Ornamental railings should have a relationship to the stair in such a way as not to leave any openings that are bigger than what is allowed by code. Illuminated railings have been very popular and utilize the latest in lighting technologies.

Close attention should be paid to the flooring material. In a minimal design with open risers, it is possible to leave the threads as exposed structural shapes that are painted with an appropriate traffic rated coating, but such stair will produce a lot of noise, and the painted coating will be eventually susceptible to scratches. The designer will typically select a material that softens the sound transmission while providing for a durable finish. Dark materials will typically get dirty faster. If stair is close to exterior, attention must be paid about coefficient of friction of the thread. Stone and tile get slippery when wet. Abrasive nosings will provide for additional slip resistance and can be used to add flair to the design. Glass threads will utilize specialty laminated and tempered glazing designed specifically for flooring applications.

Structure of the stair will be a combination of steel or stainless steel plates, shapes, bars and tubing. Designer will identify exact configuration of shapes needed, but further engineering of the stair will be required to properly size each item. Typically, the engineering is provided as delegated design, which means the contractor will be in charge of hiring a qualified engineer and providing the final design calculations. Additional structural performance criteria will have to be met for handrails and infill guards.

Final finishing of metal depends on materiality. Aluminum will typically receive factory applied high performance organic coating. Steel may be shop primed and field painted. There are a number of standard finishes for both copper alloys and stainless steel.

Final product, when executed correctly, will end up in design magazines, on posters in design firms, and as an element of pride for everyone involved in its design, construction and execution.

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Marko Goodwin is a specifications writer at Perkins+Will, New York City. To learn more, visit www.perkinswill.com[1].

Source URL: https://www.metalarchitecture.com/articles/monumental-stair-design-considerations/

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