Project Description

“Solis Ortus” -meaning my rising of the sun is a private residence located in Pelawatte (urban context - within the capital city of Sri Lanka - Sri Jayawardenepura, Kotte). The concept of this residential house is to connect to the environment, in sites deeply embedded in the urbanised and rapidly urbanising “grid” of Colombo and its suburbs, of which the capitol city is very much a part of. The approach focuses on integrating the environment without the heat, humidity of the tropical context. On a more detailed level the approach to the building envelope is cognizant of its immediate function of sheltering the internal spaces, as well as their impact on future usage patterns. Cavity walls that ease the heat gain - left bare, freed of the need to paint over reducing life-cycle cost, inviting to the touch, changing colours and how it is perceived with the rhythm of the sun - insulated roofs, with photo-voltaic panels that render the naturally lit, naturally ventilated house a net-zero energy entity.

Gabriel residence 2
Solis ortus
Solis ortus copy
Solis ortus

Building Details

Private Residence

New building project

840 m²


430 m²

395 m²

368 m²

EURO 182,000

EURO 423



Project Team

Archt. Narein Perera - Individual Practice

Mr. Saman Gamage

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.

Archt. Dr. Narein Perera and Archt. Shashikala Ranasinghe

CQS. Sunanda Gnanasiri Quantity Surveyor

Archt. Dr. Narein Perera

Archt. Dr. Narein Perera

Climate Analysis

Pelawatte has a tropical climate and fair temperature all throughout the year. The temperature averages around 31 degrees Celsius maximum from March to April. The April is the hottest period of the year and shading is seen as the best effective method of cooling. You can find major changes in the weather during the monsoon seasons from May to August and October to January when heavy rains can be expected. The solar radiation during the day sometimes border on intolerable because of the combination of heat and humidity.

Solis ortus

Design Approach

The conceptual approach to the creation of spaces that can overcome the negativities of building in the urbanised tropics was one of “Layers”. Layers that look to distance and isolate. Layers that filter and insulate. Layers that protect and create freedom. Ultimately – layers that welcome “the rising of the sun”. The layered approach emanates from the zoning of site and spaces, right down to the minute detail, thus, each level of intervention is deemed essential to the whole.

The most creative approach in the design is the integrating the site context with the building. The parameters of the urban context and the definitions of the residential house was clearly understood by the architect and he has used the land edges as boundaries to zone the street and residential site. Protective layers, in particular the aircrete block screen wall on the street edge and bamboo tat screened steel grilles create a further envelope at the edges of the open spaces, allowing almost all of the living, eating and sleeping spaces to be almost devoid of formal doors and windows. The space flows unimpeded both horizontally and vertically, again expanding the physical space to encompass experiential combinations that the home owner has the liberty to control by the act of simply opening or closing a tat screen.

Passive solutions were initiated from the building orientation onward. Having the long edges of the major habitable spaces facing north-south orientation the architect managed to capture major wind funnels in the context. Service areas such as kitchen and store rooms located to avoid the heat gain to indoor spaces on the east and west edges. The central courtyard in the building helps to circulate fresh air within the building. The interconnected open spaces encourage cross ventilation. Shaded courtyards create series of cool islands with evaporative cooling on the site. The complexity of this is integrated with both large and small courtyards connected with series of spaces. The intergrating daylight is another passive design decision made. Extensive planting utilised is - by design - for shade and insulation. and evaporative cooling
1 site  context plan narein perera


Special Feature

The integrating daylight is a passive design decision made. Extensive planting utilised is - by design - for shade and insulation. and evaporative cooling. Horizontal shading canopies and pergolas shade fenestration and walls on the upper level, while cantilevered plant troughs shade the lower levels.

The main approach is to direct the rainwater for the garden, replenish the ground water and minimise run-off, especially outside the site. Turfed roofs with a minimum of 300mm of earth, water spouts and collection points at ground level, together with a below ground network of perforated pipes augment this process.

The shaded building envelope is the strongest element in the design. Screens and extensive vegetation use enhance and facilitate the approach.

The focus is on life cycle cost, with materials and finishes that need little maintenance and no need for periodic painting etc. Cost implication - Low

Limited material usage for doors and windows. Large openings with bamboo tat screens used as an alternative. Timber utilised for essential spaces for security and privacy, adopt farmed timber species with water based clear protective coatings.

The landscape encompasses indigenous fruit, flowering trees and climbers as the main focus in space making.

Building Material

Load-bearing masonry and RCC frame structure

RCC individual pad footings and random rubble strip foundations

Exterior walls are made of exposed brick 225mm thick. The load bearing brickwork adopt the rat-trap bond in its construction. This ensures an air gap that promotes insulation of the spaces by the envelope. North facing air-crete block screen wall provides both security and shade to the major habitable spaces. The perforated wall allows the free movement air to the internal spaces

The fenestration takes the form of openings devoid of windows/glazing. Instead are sheltered using bamboo tat. Selected areas use timber louvered, sliding folding sashes, that allow ventilation and also the possibility to open fully.

Interior floors are finished with cement floating, cut and polished. Exterior areas use random rubble paving on compact soil fill, with gaps that allow grass to grow in-between and water to penetrate into the ground.

Floor finishing utilises cement float, cut and polished for interior areas. Exterior areas are of random rubble paving on compact earth, with sufficient gaps for grass to grow and water to penetrate into the ground.

The roof is made of insulated profile steel sheets, that includes a timber ceiling. The roof is covered with series of solar panels. Solar panels also serve as a protective layer reduces the direct heat gain from sun. The wing that have the long sides east/west have a flat roof, that includes a minimum of 300mm of soil and extensive planting to insulate and shade.

The boundary walls are re-used / existing structures. Structurally stabilised, built on or reduced in height to meet the needs of the spaces.

Energy systems

Custom designed luminaires use Compact Fluorescent Lamps.

Compact fluorescent and LEDs

KDK (51-57W) / 1 per room except the living room

split type - for one room only


The residence is designed for natural light and ventilation. So much so sealing of the spaces for mechanical cooling is a special effort. A single room housing the nursery and room for a new born was designed as an air-conditioned space. This too primarily for sound insulation and extra protection from tropical insects. All lamps in the custom designed luminaires are either CFL or LED. The CFLs are predominant in the interior spaces. A Solar water heater is adopted for the supply of hot water.

Solar PV, net-metered systems take the bulk of the lighting and plug loads. A Solar water heater is adopted for the supply of hot water. A distinct difference is seen in the use of the air-conditioner at latter stage of the occupancy, where, the PV system not designed for the air-conditioning consumption, resulted in the use of grid electricity. The systems advantage of being net-zero was compromised by this factor.
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Lessons Learned

The receptiveness of the clients to the approach is deemed a great advantage in the project. Two years on, the use of the premises have not seen changes that go against the original concept. The garden remains the primary space of the home, both at upper and lower levels.

The connection between inside and outside is the appreciated factor in the residence. The blurred edges in / out are a welcome feature. Though thermally comfortable, there was a need to insulate a single room for sound and tropical insects, for the benefit of a new born. The post occupancy evaluation took the form of informal discussions, and continued advise sought by the occupants.

The approach was low maintenance finishes. Only changes that are experienced were in terms of a single air-conditioned room.