London-based practice O’Sullivan Skoufoglou Architects has drawn inspiration from Charles Moore’s aedicular houses built in California in the early sixties to design a house on the edge of Gruneswald Forest outside Berlin.
Located in the southwest district of Dahlem, Euskirchen, about 12km outside of Berlin’s city centre, Dahlem House sits on the edge of Gruneswald Forest. In an area characterised by its leafy streets and largely 20th Century residential stock, the prevailing language is one of elaborate façades in Art Nouveau, Art Deco and overt Neoclassical influences – all bound by their proximity, bordering the Grunewald Forest. The house that formerly occupied this site, a single-storey ex-army bungalow built as part of a network to house colonels and lieutenants during World War II, was a low-pitched, hipped-roof form with a cellularised interior, all no longer fit for the client’s present-day needs.
Located on a quiet residential street on the edge of Grunewald Forest in Berlin, the house sits on the walls of an existing single-storey dwelling. The work comprised the removal of its pitched roof and the addition of a two-storey volume, the form of which was largely generated by local planning laws. A limestone band wraps the house at first-floor level, expressing the point where the existing building meets the new.
Taking the line of the existing single-storey house as a base, much of O’Sullivan Skoufoglou’s work involved retention of the existing structure, alongside the removal of the existing pitched roof and the addition of a two-storey volume, the form of which was largely dictated by local planning laws. The brief sought to reconcile the linearity of the site with the need for internal connections at different levels. Considering how to approach this at the outset, the architects recalled Charles Moore’s theories of ‘aedicular’ houses built in California in the early sixties, where parts of the volume were carved out to accommodate stairs and voids. In this case, a rectangular framed void, central in the plan, surrounded on three sides and open to the south, abuts the main entrance portico.
A portico provides a covered threshold to the recessed entrance at the side of the house. Doors and windows combine energy- efficient triple-glazing with solid oak frames. Hard landscaping uses the same limestone as the façade in a mix of finishes and sizes.
Amalia Skoufoglou, director at O’Sullivan Skoufoglou Architects explains “We envisaged life rotating around this central node on the upper floors that both connects and allows one to be alone to pursue different activities.” At ground floor level, the void is encircled by the sitting room to the East, and kitchen/dining as well as a family room to the west. Adjacent, and running parallel to it, is the main stair, offering glimpses at half landings, and observing a family in constant motion. At first floor, bedrooms overlook this void, while at second floor a playroom and yoga studio bring another level of dynamism to the centre.
This centrality, or unity, in the plan, is further strengthened by a carefully curated palette of materials and specifications all selected for their robust expressiveness and long-lasting durability. The use of ash throughout the interior for the stair and associated storage joinery is not only a nod to the family’s Irish heritage, but also brings a functional calmness to the space. Overhead, structural elements such as roof beams are carried out in Oak. Below, a terrazzo floor unifies the plan, allowing key elements such as the quartzite emerald green of the kitchen countertop, and solid oak joinery for the pantry to become the focus of the space.
View from the family room looking south towards the dining area.
Externally, the upper volume utilises a low carbon mass timber structure, fabricated for the most part off-site and brought in as panelled units, complete with layers of breathable wood fibre insulation that achieved a quick installation period of two weeks. Brick is laid in a simple stretcher bond, with coloured lime mortar applied over the face and worked into the joints, then beaten back and brushed with a churn brush. The self-supporting, partly rear-anchored limestone façade that tops the ground level brickwork came directly from Dietfurt, one of the oldest quarries in south Germany. The operation uses sustainable practices including re-naturalisation after extraction. The material is very dense and highly abrasive resistant, making it suitable to use in larger format in the entrance portico.
Throughout, the connection between the existing, retained structure of the old and the new extension is visibly reinforced through a limestone band that wraps the house at first floor level. The architects explain how “Much thought went into the choice of materials and specification, testing different textures and combinations of masonry elements seeking to make robust surfaces that appear heavy, long lasting and in need of little maintenance over the years.”
View from the kitchen/dining area towards the living room looking west through the full-height void. A terrazzo floor unifies the plan, allowing key elements, such as the quartzite emerald green of the kitchen countertop to become the focus.
The centrality of the void also serves a role in passive ventilation. The location of the windows is specific to the views they frame and the shape of the walls in which they are cut. The large format openings at ground level offer views of the woods at the rear and the sleepy residential street to the front, while also enabling passive ventilation through the centre of the plan. The windows in the bedrooms face south, offering warmth and maximum light during winter months. The building is heated and cooled using geothermal and solar energy, without reliance upon gas. Fresh air is maintained both passively in summer and with the aid of MVHR in the winter months. The external doors and window manufacturer sourced certified, solid oak for the main glazing profiles and linings, configured with energy efficient triple glazing, using non-toxic, safe, natural oil finishes.
Large windows give the sitting room a direct realtionship with the landscaped garden and woods to the rear of the house.
The void also sets up an organisational device that, on a practical level, allows rooms to take full advantage of the linearity in the plan, but on a poetic level enables opposing characteristics of the site to emerge. To the east, the kitchen, family room and study areas adopt a modest, even muted, relationship to the bordering Fohlenweg Strasse, providing an inward focus for repose and reflection. By contrast to the west, the sitting room adopts a direct relationship to the landscape garden beyond.
“As part of the garden design, we wanted to make a connection with the wooded area that lay beyond the boundaries of the site,” Skoufoglou explains. “Despite the charm of the vast lawn, the temptation to wander into the forest and stand beneath the dense tree canopy was always present.”
Top-floor bathroom. The use of ash and oak throughout the house brings a functional calmness to the interiors.
Resolving the two-metre level difference between the terrace and existing garden without the need to import tonnes of soil was key to the success of this connection. Fortunately, a solution arrived once the bore holes were dug for the ground source heat pipes. The excess sand was used to landscape the north side of the garden, introducing two primary paths. With the aid of hedges and trees, a meandering north path was introduced, leading slowly down into a seated area at the bottom of the garden, while another path provides stepped access on the south side directly into the woods.
View from the master bedroom on the first floor. Full-height doors allow for connectivity across the void and between the different floors.
A full-height rectangular void abuts the entrance, providing glimpses of activity on the floors above.
“The views from the terrace encouraged you to look into the forest beyond, which visually extended the size of the garden,” Skoufogolou explains. “While the larger trees and hedges provide the backdrop, the perennials create changing mood with texture and colour.
Not only a successful extension to the house, the landscape garden showcases the success of collaboration between the architects and landscape designer Grasgrau, whose vision for adding to and enhancing the existing, 200 +-year-old Scots Pine trees and birch woodland went beyond the brief by adding multi-stemmed birch, beech and oak trees, as well as staghorns closer to the house giving a striking autumnal backdrop. O’Sullivan Skoufoglou’s response to this is visible in the hardscaping, a mix of different size and finish of pavers, made of the same limestone as the façade. The choice of oak for external window and door frames pre-empts the weathering of these untreated elements, with the intention of taking on the patina and assimilating the house into the surrounding woodland in years to come.
Rear view of the house. The landscape has been designed to reflect the character of the surrounding woodland.
More images and drawings
Architect
O’Sullivan Skoufoglou Architects
Executive Architect
Tectur
Structural engineer
Karg Ingenieure
Environmental Engineer
Bernd Horn
Electrical Engineer
Resto
Project Manager
Weert Schulz
Main Contractor
Sibuna Bautraeger
Landscape Architect
GrasGrau
Mass Timber Specialist
Schaefer Fertighaus
Mass Stone Specialist
Naturstein Wachenfeld
Source: Architecture Today
