Not to be outdone by neighbouring retailers on 5th Ave, Tommy Hilfiger commissioned Callison Architects to develop a monumental stair. The resulting design was a detailing and coordination challenge that fit perfectly with the Feature Walters methodology.
As is often the case, the Hilfiger staircase began with a spectacular concept and a rendering from the client. The Photoshop rendering depicted a seamless white stair spiraling up through three storeys of a century-old building.
Our inclusive proposal solved all of the project’s concerns with quality, coordination, schedule and budget. We reconciled the variations between levels into a single cladding geometry, allowing all molded parts to come from a typical mold – saving time and money; engineered a unique structure – using the architect’s design intent as the driver for the form; coordinated all materials in our HD-BIM model and managed the production, procurement and install of all materials.
Once the cladding geometry was resolved, we began the reverse engineering of the structure to fit the final form. The slender cladding did not offer much sectional depth and each flight imposed significant forces on the cantilevered landings. This called for some unorthodox engineering of the stringer and landings to keep the visual mass of the cladding as light as possible.
With the cladding form approved and the steel engineered, our production clock started ticking. The power of our 3D model came into play here allowing all long lead time items to be produced in parallel. The fit and finish requirements on a complex geometry across multiple finishes was further compounded in the continuous nature of the stair. Since it was never interrupted by a landing, there was no opportunity to reset the geometry – any creep in dimension or position would be accumulating through the three storeys.
CNC cut files and tight QC ensured parts confirmed with the model. CNC produced fixtures and jigs controlled the geometry of the steel in fabrication. Glass from the US and exotic hardwood treads from Brazil (machined to maintain a constant 1/4” offset from the constantly curving cladding) were also produced from our CNC files.
Not only were the treads precision milled, they included programmable RGB LED lighting and a flush soffit. All of the wood, soffit, mounting details, electrical feeds, LED pucks and structure fought for space in the 2” tread slabs – each numbered for a specific location in the elliptical stair – then floated off the cladding with hidden supports and wired into the LED drivers.
Our final act of coordination was a series of CNC templates that were surveyed and anchored to site, allowing the demolition, slab edge work and adjacent finishes to proceed with the accuracy required to receive the stair.
All of our materials converged on site where they were assembled for the first time, seamlessly.