Specifying Material and Finish for Architectural Components
Material and finish are a single decision on a visible component. Each material carries its own finish path, and the pair has to be settled together.
On a component nobody sees, the finish is protection. On a visible component it is the design, and the material underneath decides which finishes are available. Two decisions, one outcome, so they belong on the drawing together.
Carbon steel, and the coating that comes with it
Carbon steel is the default structural material and it needs a coating to stay that way. Powder coating runs through a partner shop, in standard neutrals and bold colours from the Cardinal range. What matters at specification is the colour reference, the gloss or texture, and which faces are exposed.
A carbon steel component with no finish specified is a component that will rust, and it is worth saying so on the drawing rather than discovering it at delivery.
Stainless steel, bare or coated
Stainless is often specified for the surface rather than for corrosion, and the finish then depends on how it is processed. A laser cut edge and a machined edge read differently, and the grain direction on a visible face is a drawing note if it matters. Stainless can also be coated, but coating over stainless is usually a desire for colour rather than protection.
Aluminum
Aluminum is lighter and works well for visible elements where the weight matters. Anodized finishes are mentioned in commercial project discussions, and where an anodized finish is required the arrangement is confirmed at quote rather than assumed, since finishing is coordinated through partners rather than performed in the building.
Weathering steel
Corten is specified because of what it does over time: it develops its own surface rather than holding a colour. It is also the material most often specified with the wrong finish. A clear coat changes how it weathers, and a colour coat defeats the reason for using it. Say which behaviour is wanted.
The three lines that prevent most problems
- The material by name, not by description. "Architectural metal" is not a material.
- The finish with a reference, or an instruction that the component is to be left bare and unprotected.
- Which surfaces are visible after installation, so the shop knows what the part is judged on.
Where this sits in the process
The material and finish pair also affects fabrication: thickness capacity differs by material, and coating happens after welding and before delivery. What to specify when components need powder coating covers the coating specification itself, and what helps a fabrication quote move forward covers the rest of the information a visible component needs.