Commissioning an Architectural Metal Installation: A Guide for Architects & Developers | FormForge

A commissioned metal installation is not a product selected from a catalogue. It is a fabricated response to a specific site, structure, and intention — engineered to load, weathered to context, and installed to permanence. This guide sets out how that process works, for the professionals who specify it: what determines material, what governs cost, and where a fabrication partner earns or loses the project.

It is written for architects developing a landmark, developers anchoring a lobby or forecourt, and consultants advising on public or hospitality art. It assumes you are specifying work, not buying an object.

Material determines everything downstream

The material decision is made first because it governs weathering, structure, maintenance, and cost simultaneously. For architectural metal installations, three materials carry most commissioned work.

Corten (weathering) steel

Corten develops a stable oxide layer that arrests further corrosion — the patina is the protection, not a coating over it. It suits outdoor and landscape settings where a warm, earthen surface is wanted, and where the material is permitted to mark the ground and structures below it during the weathering period. Specification note: runoff staining during the first weathering cycles is real and must be planned for in adjacent hardscape and drainage.

Stainless steel

Grade 316 stainless holds its surface indefinitely in humid and coastal conditions where 304 would eventually tea-stain. It carries mirror, brushed, and bead-blasted finishes, each reading differently under changing light. It is the specification for interiors, atria, and any coastal exterior where the surface must stay bright rather than weather.

The weld line as a design decision

In fabricated (as opposed to cast) work, the weld seam is a visible fact of construction. It can be ground invisible, or it can be left as an expressed line that records how the form was built. This is a design decision to make early with your fabricator, because it determines both the surface language and the finishing labour — and the two directions cost differently.

What actually governs cost

Commissioned metalwork is priced on labour and engineering, not material weight. A useful mental model separates four cost drivers:

Scale and structure. Anything monumental requires internal armature, engineered anchoring, and load calculation — often the single largest line item, and one that has nothing to do with the visible surface.

Geometry. Faceted, doubly-curved, or parametric forms multiply cutting, forming, and fit-up time. A simple planar piece and a complex crystalline one in the same material and size are not comparable costs.

Finish. Mirror-polishing stainless is an order of magnitude more labour than a brushed surface. Expressed-and-cleaned weld seams sit between the two.

Site and installation. Access, crane requirements, foundation coordination, and travel distance are project costs that exist before the first cut. For a detailed treatment of ranges and what moves them, see our guide on what a commissioned sculpture costs.

The commissioning sequence

A well-run commission moves through predictable stages. Knowing them lets you coordinate the installation against your own construction programme.

1. Brief and site reading. The intention, the sightlines, the structure it attaches to, the light it sits in. For site-specific work this stage determines everything that follows.

2. Design development. Sketch to 3D model to fabrication drawings, resolved against the real constraints of the site and the budget.

3. Engineering. Structural resolution of armature, connections, and anchoring — the part that makes a large piece safe and permanent, and the part a purely artistic supplier often underestimates.

4. Fabrication. Cutting, forming, welding, finishing. Photo-documented against the drawings.

5. Site installation. Foundation coordination, transport, placement, final fixing. Handover.

Where to place the work

Different settings ask different things of a metal installation. FormForge's commissioned work spans:

Public art installations — civic and urban landmarks that must resolve wayfinding, scale, and public durability. Architectural metal sculpture integrated into facade, atrium, or courtyard. Hospitality installations where the piece anchors arrival and guest experience. And landscape and garden work sited into planting and topography.

What to ask a fabrication partner

Four questions separate a capable commission partner from a supplier:

Can they show engineered anchoring on comparable-scale work, not just finished photographs? Do they fabricate in-house, or subcontract the actual metalwork? Will they take site and installation responsibility through to handover, or deliver to your loading dock? And can they hold a coherent design intention across the whole piece — or does the work fragment into competing ideas?

If you are developing a project and want to test a brief against material and structure, start a conversation with the studio.

Common questions

How long does a commissioned metal installation take?

Most architectural commissions run from design brief to installed work over several months, driven by engineering and finishing rather than fabrication alone. Monumental or heavily engineered pieces take longer and should be coordinated against the construction programme early.

Corten or stainless steel for an outdoor installation?

Corten for a warm, weathered surface in landscape and civic settings where staining during the weathering period can be accommodated. Grade 316 stainless where the surface must stay bright, or in coastal and highly humid conditions. The setting and the intended surface language decide it, not a general rule.

Do you engineer and install, or only fabricate?

Commissioned architectural work is carried through structural engineering, fabrication, and site installation to handover. For large-scale pieces the engineering and anchoring are as much of the work as the visible form.

Can a piece be developed site-specifically for our project?

Yes — site-specific commissions begin from the site itself: its sightlines, structure, and light. This is the difference between an installation that belongs to a place and an object placed within it.