Designed by Geoffrey Bawa and Ulrik Plesner in 1963–67, the Polontalawa Estate Bungalow in Sri Lanka is an example of the architects’ adaptive and environmentally responsive approach often known as Tropical Modernism. It was built as the estate manager’s residence on what was then a remote coconut plantation in Nikaweratiya in the dry North Western Province. It is noted for its incorporation of the site’s rocky outcrops, with extensive permeation between the interior and exterior spaces, and its use of local materials and traditional Sri Lankan techniques.

The bungalow was commissioned by Thilo Hoffman from the Swiss-run Sri Lankan firm A. Baur & Co., who asked for a house modelled on the prefabricated structures displayed at the Ideal Home Exhibition in London in 1959. Having initially presented a design similar to a previous house they had designed in Anuradhapura, after visiting the site Bawa and Plesner suggested a revised proposal, which involved shifting the proposed house to a part of the site with large boulders. The house would be divided across multiple units among the boulders, which would themselves be used as structural elements, an idea that Hoffman was immediately agreeable to. 

In a further departure from conventional colonial architectural practices, the bungalow was designed directly on the site using sticks and strings, without any initial architectural drawings other than a rough preliminary sketch envisioning the house. The architects adopted this approach in order to best integrate the boulders into the design — by being physically aware of their scale and stability, as well as the play of light and the circulation of air in the space. They planned the structure with the contractor and client present, and directly supervised the construction, which was largely carried out by the estate workers. The only known site plan was made in 1967, after the building was completed. 

The bungalow is surrounded by a large open area on all sides, encircled by a rubble perimeter wall interrupted by boulders and large trees; a small, roofed gateway allows entry into the compound. The bungalow is built as a cluster of connected spaces, entered from the east through a space between two boulders. This leads to the main living area, a long space open on three sides, doubling as a verandah. It is covered by a pitched roof set on a large concrete ridge beam fitted onto the large boulders at either end. Separate pavilions hosting bedrooms for the estate manager and guests are located off one end of the living area; at the other end, a narrow corridor leads to the kitchen, the estate office and a water tank.  

The design and construction of the bungalow reflect key features of the Tropical Modernist style pioneered by Bawa. The incorporation of the boulders into and among the built structures, with minimal cutting, creates a close interplay between natural and built environments. It also recalls ancient Sri Lankan rock-cut architecture, such as the Dambulla cave temple and the Sigiriya fort, which historians have noted as being among Bawa’s influences. The paths through and between the built spaces wind around these boulders, variously comprising covered and open walkways. In general, there are relatively few enclosing walls, allowing for greater interaction between the outside and inside spaces; in the largely open main living area, an arrangement was made for movable rattan (woven palm) screens — locally made and traditionally used in the region — for protection from rain. These screens could be hung on either side, depending on the season. Walls, where constructed, are made using rubble from the immediate surroundings, also creating a visual continuity with the large boulders; these include the walls for the residential structures, the office, the kitchen and the water tower. Other local materials used include wood for the columns and rafters, terracotta barrel tiles for the pitched roof. The overall effect is of the building ‘growing’ out of the ground.

Following the Land Reform Law (1972), the Polontalawa Estate Bungalow and its surrounding area were taken over in 1974 by the National Livestock Development Board of Sri Lanka. The estate is now used as a farm and office space while the bungalow itself is largely preserved in its original condition.