house Na Stolbi


2020 - 2021


Ljubljana, Slovenia




Majda Kregar

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  • YEAR : 2020 - 2021
  • LOCATION : Ljubljana, Slovenia
  • CREATIVE DIRECTOR : Majda Kregar



The building ‘Na Stolbi 8’ is located on the castle hill next to the route of the funicular. Ljubljana Castle Institute needed additional business premises for castle’s administration, and the location was suitable due to its proximity. The design brief required offices for individuals from institute’s various business branches, which would offer an environment enabling concentrated, undisturbed and more demanding work. In parallel, two apartments were to be built, to support the cultural programs of the castle, as occasional residences for visiting artists.

An almost zero-energy wooden building had to be built on a limited plot of an old building and for a precisely defined budget. It is a relatively small facility with many requirements, in a visually sensitive and constructionally demanding location, which was further complicated by the combination of very different programs by nature.

We designed the main building with an extension into the castle hill, placed in a narrow area of the steep hill. In the main, wooden building, there are offices on the ground floor and two apartments on the upper floor. The dug-in part of the auxiliary building is made of reinforced concrete and serves as a service area and a meeting room.

The main building is designed as a square ground floor and a trapezoidal, somewhat cantilevered floor with a terrace. The roof is flat and green. The construction is entirely wooden: the columns and beams are made of glued spruce wood, and the ceilings and most of the walls of cross-laminated timber panels. The building looks simple on the outside, structurally that is not the case. In addition to good thermal performance, strict acoustic and fire requirements were also required, since different programs (business and residential) must be completely separated in this respect. This required a demanding implementation of the installations in the wooden structure.

The house meets the requirements of almost zero energy loss also owing to the installation of special, patented glazing (developed by domestic manufacturer Reflex d.o.o.), made of four chambers, installed for the first time in Slovenia. Reflex cooperates on larger buildings in Norway. Q-Air glazing, Ug value of 0.27 W/m2K, g=0.34 heat gain, has excellent insulating properties and requires no external blinds.

In addition to the large glazing, the facade consists of slatted wooden cladding, making the building appear lighter, merging it with the surroundings. Intensive greening will eventually integrate it with the forest around it. Even the glass facade has steel wires for climbing plants.

During the construction the existing retaining wall of the northern terrain shelf in front of the building (made of stone) had collapsed. Due to limited resources a new wall was built of concrete, but it is planted with ivy and will turn green with time.

The dug-in building made of reinforced concrete has a double retaining wall facing the hill. Its roof is topped with soil, greened and merges with the vegetation of the castle hill.

The courtyard facade of the dug-in building is made of raw concrete, which expresses the contrasting solidity of a backfilled building next to the light, wooden one.

In this way, we imprinted the program non-aggressively onto the hill and visually highlighted the wooden structure with large viewing windows, which provide enough light and a pleasant working environment in the shadow of a steep northern slope, which with time will become beautifully overgrown.