上空へとオフィスを拡張する〈HOVER SPACE〉

Ⓒ Andre Fanthome

インドの都市ベルガウムに建つ〈HOVER SPACE〉は、インドの歴史ある教育慈善団体のオフィスの拡張プロジェクトであり、既存オフィスの上部に浮かぶ空間として設計された建築です。

インドに拠点を置く サードスペース・アーキテクチャ・スタジオ（Thirdspace Architecture Studio）が設計しました。

注目ポイント

• 常時稼働中のオフィス業務を妨げない、上空への増築
• 都市に対する視覚的ランドマークであり、キャンパスの顔としての象徴的な存在
• トラス構造と8本のコンクリート柱で実現した柱のない大空間
• 気候調整と社交スペースを両立する、外周を囲む連続したベランダ

（以下、サードスペース・アーキテクチャ・スタジオから提供されたプレスキットのテキストの抄訳）

Exploded Axometric

既存の建築を、そのアイデンティティを維持したまま拡張することは可能だろうか。新しい増築部分が古い部分と調和、共存し、それぞれの独自性を保ちつつ、一体感のある全体を形成するにはどうすればよいだろうか。

これらの問いは、著名な教育慈善団体から、50年以上の歴史をもつ2階建てのオフィスに追加のスペースが必要となった際に私たちに投げかけられた。既存のオフィスに外観上の特筆すべき点はないが、団体の歴史の中で重要な位置を占めており、保存が望まれていた。

オフィスは常に活気に満ちており、すでに改修工事を実施していたため、オフィスの機能を妨げることなく拡張する必要があった。

Ⓒ Andre Fanthome

都市のランドマークであり、キャンパスの顔でもある新たなオフィス

建物は多様な文脈に対応する必要があった。

このオフィスは、教育慈善団体の100年以上の歴史をもつ広大な100エーカーのキャンパスの一部として、都市の主要道路沿いに重要な位置を占める構造物であり、この重要な都市道路沿いにおける視覚的なランドマークとして機能することが不可欠であった。

Ⓒ Andre Fanthome

木々の豊富さと低層の建物により、キャンパスは都市から見ると境界壁のように見え、キャンパス内部の景色はほとんど見えなかった。このことから新たな建築は、キャンパスのアイデンティティを強化しつつ認識しやすくする、慈善団体の歴史的なキャンパスの正面をなす要素の1つとして機能することとなった。

また、建物はスポーツグラウンドに隣接しているため、新築部分はスポーツグラウンドの周辺緑地の一部となることも考慮する必要があった。

Ⓒ Andre Fanthome

既存建物の上空に増築するプロジェクト

これらの条件から、増築部分は既存の延長ではなく、建物の上部に浮遊する構造物として設計し、地面との接触は最小限に抑えることとした。

設計の核心は空間を生み出す大きなトラス構造であり、地面レベルでは8本の円筒形のコンクリート柱で支えられている。これらの柱とトラスにより、約1,000m²の連続した内部空間を実現した。

Exisiting Building

Construction process

立面では、逆L字形のデザインを採用した。垂直部分には動線とロビーを配置し、水平部分は既存建物の上に浮かび、スポーツグラウンドに向かって伸びている。この垂直部分は、建物を地面に視覚的に固定している。

建物のL字形は、道路からキャンパスへと入る目印となり、いくつかの歴史的建造物が並ぶ中央の樹木に囲まれた大通りへと導いている。

Front Elevation

Longitudinal Section

ベランダとしての第2のスキン

柱のないシンプルな箱状のオフィス空間は、コロニアル建築の普遍的で反復的な特徴から着想を得た連続したベランダで包み込まれており、地域の過酷な雨と日差しから内部を保護する気候緩衝帯としても機能する。

内部と外部の中間エリアであるベランダは、多様な用途をもつ社交空間として機能するだけでなく、オフィスの休憩スペースとしても機能する。深紅に塗装されたトラス構造は、オフィス空間とベランダの境界を定義する彫刻的な要素として機能する。

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

東側と西側の長いファサード沿いには、操作可能な垂直フィンを備えたアルミメッシュスキンを採用し、気候制御と透明性をさらに高め、直射日光をフィルターする。内部空間からの眺めは、トラス、ガラス窓、ベランダの植物、アルミメッシュスキンによって層状にフレーミングされている。

これにより、オフィス空間は都市の喧騒から離れた聖域をつくり出し、透明な層を通して周囲に広がるキャンパスを垣間見ることができる。内部空間は、豊富な自然光、換気、白と明るい色を基調としたシンプルなカラーパレットと豊かな緑が調和している。

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

既存建物を覆う新たなスキン

建物の改修の一環として、既存建物を軽量アルミルーバーで覆うことで、新築部分と視覚的に一体化したデザインを実現した。垂直のアルミフィンで構成されたルーバーは、上部に浮かぶ金属構造に敬意を表しつつ、独自のアイデンティティを確立している。

Ⓒ Andre Fanthome

新旧のオフィスを分離しつつつなぐ空間

機能的にも概念的にも、新築部分は既存建物と視覚的に区別されつつも、一体的に機能する必要があった。それぞれの建物は、キャンパスと周囲の景色を静かに望むことができるスポーツグラウンドに面したガラスエレベーターで接続されており、両建物を物理的に接続している。

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

既存建物のテラスは、イベントスペースやテラスガーデンとして機能する空間となる。この中間的な空間は、視覚的・機能的に新旧のギャップを埋める緩衝材であり移行点として機能する。このテラスには、新築部分と接続する彫刻的な螺旋階段も備えている。

既存建物に対する新築部分の配置により、テラスの一部は空に開かれつつ、他の部分は上部が覆われている。

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

Ⓒ Andre Fanthome

Sectional Perspective

Site Plan

Ground Floor Plan

First Floor Plan

Second Floor Plan

Third Floor Plan

Detail

以下、サードスペース・アーキテクチャ・スタジオのリリース（英文）です。

Project Information

Project Name: HOVER SPACE – Extension to the KLE Society Head Office
Office Name: Thirdspace Architecture Studio
Office Website: www.thirdspacearchitecture.studio
Social Media Accounts:
Instagram: https://instagram.com/studio_thirdspace?igshid=NDk5N2NlZjQ=
Facebook: https://www.facebook.com/thirdspacearchitects/
Contact email: jobs@thirdspacestudio.net
Firm Location: Belagavi, Karnataka, India
Completion Year: 2024
Gross Built Area (m²/ ft²): 1200 Sq.m
Project Location: Belagavi, Karnataka, India
Program / Use / Building Function: Office Building
Lead Architects: Praveen Bavadekar, Principal; Namrata Betigiri, Principal
Structural Design: D.L.Kulkarni & Associates, Belagavi
Photographer: Andre Fanthome (Noughts & Crosses), Suryan and Dang

Project Description

Can an existing structure be expanded while preserving its integrity and identity? How can the new addition coexist harmoniously with the old, while maintaining their distinctiveness and also forming a cohesive whole?

These were the questions we pondered when a well-established educational charity institution required additional space for their five decades old, two-storey corporate office. The existing office, though unremarkable in appearance, held significance within the collective memory of the institution and was desired to be retained for its historical value.

The office was always bustling with activity and had previously undergone a retrofit, so any expansion on top had to be executed in a way that wouldn’t disrupt its functioning or cause damage to its interiors through intrusive structural modifications. Hence, the challenge was to intervene in a manner that wouldn’t affect the existing office’s operations or harm its interiors.

There were several contextual factors to consider, such as the location on a prominent city road, the presence within the century-old campus, and its adjacency to the sports ground.

The City Artery:

The proposed building needed to respond to its various contexts. As part of a sprawling hundred-acre educational campus, the structure occupied a significant position on a major road in the city. It was essential for the building to establish itself as a visual landmark along this important city road.

The Campus:

The new building would also serve as one of the frontages of the century-old campus, which held great historical importance for the charity organization. Due to the abundance of trees and the low-lying nature of the buildings, the campus appeared as a inscrutable perimeter wall from the city, offering limited views of the interior. This presented an opportunity to create an intervention that would enhance the campus’s identity and make it recognizable.

The Sports Ground:

The campus’s sports ground bordered the head office building. While the existing building went largely unnoticed from the ground, the new addition would be a part of the peripheral edge of the sports ground. Thus, the building had to respond to these three contexts and be viewable from these vantage points.

Strategy:

After thorough analysis, a three-fold response to the requirements was conceived:

1. The new structure wouldn’t merely be an extension or continuation of the lower floors. Instead, it would be a floating structure above the old building, barely touching the ground.

2. The building had to adapt to the three distinct micro-contexts: the road, the colonial-era campus, and the adjacent sports ground. Its height was limited to 15 meters due to fire regulations, and its footprint was constrained by road setbacks, existing buildings, and proximity to the ground.

3. The construction of the new building had to be carried out without disrupting the functioning of the existing campus.

Resolution:
Structure as Space:

The proposed addition is conceived as a hovering space above the existing building, causing minimal disturbance at ground level. At its core, the design features a space between two full-floor-height edge trusses. These trusses are supported by just eight carefully positioned cylindrical RCC columns, avoiding obstacles at ground level.

These peripheral columns allow for a seamless and uninterrupted interior space of approximately 1000 sq.m. The width of the office on top is limited by the existing context and the need for daylight penetration throughout the interior. The length of the space is similarly restricted by the ground on one side and a historically significant garden on the other.

In elevation, the design resembles an inverted L shape, with a vertical arm containing circulation and a lobby, and a horizontal arm floating over the old building and extending over the sports ground. The vertical circulation element thus anchors the building visually to the ground on one side while giving it a floating appearance in the background of the sports field on the other side.

The L shape of the building creates an entry portal from the road to the campus, aligned with a central tree-lined avenue that showcase several heritage structures.

These structures are framed through the triple-height entry portal, offering a captivating view of the campus from the road.

Verandah as a Second Skin:

The simple box of column-free office space is further enveloped by a continuous verandah, drawing inspiration from a ubiquitous and recurrent feature of colonial architecture in the subcontinent. The verandah serves as both a social space with diverse uses and as a climatic buffer, shielding the interiors from the region’s harsh rain and sun.

This verandah also provides breakout spaces for the offices and acts as a transitional zone between the interior and exterior. The floor-height trusses, painted in deep red, serve as sculptural elements defining the boundary between the core office space and the verandah. Aluminum sliding doors act as an interior envelope, providing easy access to the verandahs.

An expanded mesh aluminum skin with operable vertical fins further enhances climatic control and transparency along the longer eastern and western facades, filtering direct sunlight. The views from the interior spaces are layered and framed by the trusses, aluminum glazed windows, plants in the verandah, and the lightweight aluminum mesh screen.

This allows the office spaces to create a sanctuary, shielding the occupants from the city’s bustle while allowing glimpses of the surrounding campus through layers of transparency.

The interior spaces benefit from abundant natural light, ventilation, and a simple palette of whites and bright colours, complemented by lush foliage. Programmatically, the offices are divided into three main areas: the entrance lobby with the Chairman’s chambers, a middle section housing private offices and meeting rooms, and a rear section with open office cubicles offering views of the city and the sports field. Exposed roof trusses and a clerestory skylight along the center of the roof define a spine, emphasizing the main circulation corridor.

New Skin for the Old:

As a part of the refurbishment of the building, the existing structure is sheathed in a light aluminum louvre skin that allows the building to become visually cohesive with the new addition. The louvred skin is made of vertical aluminum fins that pay homage to the metal structure floating above, and yet have a distinctive identity of their own.

Interstitial Space:

Functionally and conceptually, the new addition needed to operate cohesively with the existing building while visually distinguishing itself. The two structures are connected by a glass elevator facing the sports field, offering serene views of the campus and its surroundings as one traversed vertically through the office complex.

This glass elevator serves as a physical link between the two buildings, enabling users to temporarily step out of the spaces while still being enclosed in a glass box before reconnecting back. This ritual of transportation reinforces the separation between the old and new elements.

The terrace of the old building becomes an interstitial space that could function as an event space or terrace garden. This intermediary space acts as a buffer and a transition point, visually and programmatically bridging the gap between the old and the new. Accessible from the lower floors via the existing staircase, the terrace now also features a sculptural spiral staircase connecting it to the new addition above.

The placement of the new addition in relation to the old structure creates a condition where parts of the terrace were open to the sky, while others were covered by the hovering space above.

Several Responses:

Despite its seemingly simple appearance, the new addition possesses multiple layers of complexity woven into its design. It responds to the road by presenting itself as a linear screened box parallel to the road, partially concealed by foliage. It serves as an entryway portal to the campus and acts as a backdrop for the sports ground, visually anchoring the campus.

Overall, the newly created office space endows the organization with a fresh identity and presence, while also serving as an entry portal for the broader campus. The offices, with their blend of private chambers and open work desks, greatly benefit from the exterior verandahs, shielding the interiors from the elements. In its various nuances and details, the design addresses multiple functional, contextual, and climatic considerations through straightforward strategies.

サードスペース・アーキテクチャ・スタジオ 公式サイト
https://www.thirdspacearchitecture.studio