On the corner of Lõõtsa and Suur-Sõjamäe streets, in Ülemiste City — one of Tallinn's fastest-growing business districts, close to the airport and the city's emerging transport hub — Sepapaja 1 has become something of a landmark for everyone arriving into town. Twelve storeys of simple, disciplined rectangular volume for developer Technopolis Ülemiste, its form doesn't try to be complicated — the accent comes instead from large glass facades that spiral upward around the building's perimeter, floor by floor, opening each level onto wide, unobstructed views. From the upper floors, the outlook stretches across the whole quarter to the sea and Tallinn's skyline beyond. The rest of the facade holds a calm, steady rhythm: windows a metre wide, spaced at 2.5-metre intervals, giving every desk inside its own share of daylight and outlook. Vertical aluminium composite ribs, projecting 155mm from the surface, run the height of the building in two tones — a lighter, brushed silver where they step forward, a darker anthracite where the facade recedes — reinforcing the sense of the building reaching upward rather than simply stacking floor on floor. To the south, facing the entrance, a representative plaza opens up in front of the building — as much a stage for events as it is a place for staff to take a break outdoors.
Inside, a central core — stairs, four lifts, service rooms — anchors the plan, freeing the entire perimeter for office space that flexes easily between open-plan and cellular layouts. Typical floors divide into as many as four office units of around 250 square metres each, or open up into a single uninterrupted floor plate; every configuration keeps to a consistent planning module, so tenants can subdivide or combine space without fighting the architecture. Altogether the building holds space for roughly 1,200 people across some 13,000 square metres. The ground floor carries its more public functions — a café and lunch restaurant, and a direct connection through to the new parking building next door — while the upper floors settle into pure, efficient office space. Sustainability here is less about visible gesture than compact discipline: a tight, efficient building volume, a well-insulated envelope, and mechanical ventilation with heating and cooling calibrated to keep energy use down through both Tallinn's winters and its shorter summers — performance recognised with a LEED Gold certification. After dark, the building's identity comes forward again: LED strips run vertically up the centre of each opaque facade stripe, and illuminated signage — Technopolis Ülemiste's own logo, alongside tenant signs — crowns the roofline, visible across Ülemiste City after the working day winds down.