Project Description

Right in the heart of Colombo, perched in the middle of a dense urban fabric, spanning social classes and structures that reveal a diverse community, the ‘Bird Cage’ rises in stark contrast due to its originality and perforated enclosure. It is a magnanimous response that draws together three permanent geographical concerns of building production: climate (with its connections to environmental comfort); physical form (morphology); and building materials. The physical circumstances of where we build – our sites – provide a socio-spatial complexity and system of reservoirs with which those of the building interacts. It is indeed when dealing with the compact, rectangular site - confined by adjoining houses on the longer boundaries - that this project unearthed the constraints that generate the needed impetus to innovate

Bird cage 1
Bird cage
Bird cage copy
Bird cage

Building Details

Private residence

New building project

126 m²


250 m²

207 m²

142 m²

EURO 85,000

EURO 340



Project Team

Archt. Narein Perera - Private Practice

RCC structure - NESA Builders. Timber Works - Dilum Fernando. Steel Works - Shantha

Eng. Keerthi Ratnayake

Archt. Dr. Narein Perera

Narein Perera runs a small practice, which prides itself in the degree of innovation and holistic applicability of its architectural solutions. A Senior Lecturer at the Department of Architecture, University of Moratuwa, with a teaching and research focus on climate sensitive design at both, building and urban scales, for which he holds a PhD, strives to apply 'lessons-learnt' in his practice. The practice, now over ten years old, has been quite successful over the years, winning recognition for design, both locally and internationally. On the international `stage, he was awarded the 'Architecture Asia Award for Emerging Architects' as a part of the Asian Congress of Architects sessions in Malaysia, 2014. In his home country of Sri Lanka, he was the recipient of the 'Young Architect of the Year' in 2010 and Sri Lanka Institute of Architects, awards for Design excellence in 2007 and 2011.

Eng. Sanjaya Ramanayake

CQS. Sunanda Gnanasiri Quantity Surveyor

Archt. Dr. Narein Perera

Climate Analysis

Colombo has tropical monsoon climate and has sunny days throughout the year. The city temperatures varies between 24-31 C throughout the year. During the monsoon season, Colombo gets heavy rainfalls. Usually April to May and September to November records highest rainfall figures to Colombo city. And the biggest problem with city of Colombo is the high humidity content. Cross ventilation and the shading is the best solution

Bird cage

Design Approach

The conceptual approach embraces simple form making, thus a contrast to the chaotic urban environment. The 'bird cage' was envisioned as an envelope that protects, yet allows maximum freedom within it.

The outcome is a house which synthesizes aesthetic simplicity with intelligent pragmatism and becomes a kind of prototype that can be used with a moderate degree of change and adeptness in similar kinds of compact, urban plots. For example, the clever introduction of an elevated garden space, which is experienced from all three levels of the building, can be seen as an attempt to overcome the area limitations of the ground plane and establish a spatial continuum across inside and outside, thereby blurring the boundaries of an otherwise condensed space. The terraces, together with the open spaces on the ground floor, reclaim over 70% of the plot as open to sky, garden space.

Passive features of this scheme, features the galvanized iron ‘cage’ that ties the whole composition together. Unlike the conventional solid enclosures with small openings protected with grille work, this distinctive interpretation of a ‘skeletal cuboid volume’ provides a transparent and permeable skin, defining the building form (both internally and externally) and protecting the interior and inhabitants from the adverse effects that the urban context and environment can generate. It is a ‘brise-soleil’, a vegetated skin, a visual screen and essentially, a security layer that protects the inhabitants from unsolicited activities which often occur in the immediate context of this locality. For the interior, the ‘cage’ forms and defines the habitable volumes, creating variety in the spatial flow, the comfort, and the utility. The internal spaces open out to a triple height volume, which accommodates the formal living area at its ground plane and serves as a ‘ventilation stack’ allowing a free flow of air across space and through the permeable envelope.
Birdcage sketch


Special Feature

The residence is designed for natural light and ventilation. A shaded envelope, that filters daylight and connected open spaces encourage cross and stack ventilation. The shade screen cage incorporates both horizontal and vertical elements.

Minimal run-off from a minimal built area. The planted roof terraces are use and slow the rainwater.

Air conditioned spaces are limited only to the bed rooms. This more so for insulation for sound from the busy neighbourhood, than for thermal comfort. the bedrooms are afforded maximum insulation with turfed terraces above, that are in turn shaded by the cage. possibilities for cross ventilation and whole house stack ventilation enhances cooling possibilities.

The lightweight internal structure, surface and finish are envisioned as a single entity - timber planes. Therefore, the need for finishes that become an extra layer is avoided.

Timber as a primary material choice for living spaces.

The galvanised iron steel cage is treated for longevity, with marine grade coatings. A disadvantage is that it even repels the footholds of climbing plants, deemed essential for the whole. The shade screen structure although slender, reducing cost and enhancing transparency, was designed to carry extensive planting.

Building Material

RCC perimeter structure with load bearing walls, support a light weight timber structure on the interior.

RCC individual footings and random rubble strip foundations

The primary load bearing elements are the two boundary walls facing east and west. The terraces span the width of the site and these walls. The rest of the structure is suspended, giving a lightweight, thin, timber planes separating spaces.

The full length windows are within the shade screen cube, therefore shaded both vertically and horizontally

Timber decks of 'farmed' teak on upper levels, with cement float cut and polished finish on lower floor.

Water based finishes on all timber wall panels, floor decks, doors and windows.

The roof takes a unique form that is envisioned as two layers. The shade screen and the plated / turfed roof terraces. The shade screen is open to the elements over the gardens, while a transparent polycarbonate roof with a bamboo tat screen shades the internal spaces

Marine grade protective coatings are utilised as both the finish and the protection for the GI structure.

Energy systems

All luminaires include LED lamps

All luminaires include LED lamps. Controls : Sensor switches for selected lamps only

Type / Number per rm: KDK(557W)/ 1 per room

Split type ACs for bedrooms only


Controls : Sensor switches for selected lamps only


Lessons Learned

The initial design scheme envisioned the steel screen to be planted heavily with climbing plants. Although the client initially opted for the option, but later abandoned it for easier maintenance of the envelope.

The users appreciate the aspects of daylight integration that allow the spaces to dynamic throughout the day. Artificial lighting is not needed for much the day. The filtered quality of daylight, reflected off the light coloured surfaces enhance its effectiveness.

The main concern is with regard to rain penetration in certain times of the year. The openable bamboo screens, that allow air pass through while shading the interiors cause the rain to beat in at high wind velocities. Monsoon blinds,that are transparent were later adopted as an alternate. This does not allow wind movement when closed.