Stone-Ideas.com 
“Stone Insight“: Quarrying Stone Slabs with Heat
“Chapdi“ is the magic word for this house constructed from solid natural stone in the southern Indian state of Karnataka. In local slang, the word means “stone slab“ and refers in this case to a construction in which granite slabs measuring 3650 x 750 x 100/125 mm are placed side by side to form the walls, topped with a walkable flat roof, also made of stone slabs.
Chapdis have long been used for many purposes in Karnataka, such as sidewalks or to create water channels – but the idea of using them to build an entire house came from architect Senthil Kumar Doss and his office, Play Architecture.
The production of these slabs is a very special topic, which we cover later in a separate article from our “Stone Insight“ series: The slabs are separated from the rock in the quarry using the heat of small fires. The process is ancient but requires special expertise.
In the “Interlocking Stone House“ (OHHO Residence), which is the subject of this article, the walls consist only of granite slabs and pillars. The first challenge is anchoring them to the ground. To do this, the pillars are placed in a kind of stone box in the ground. To hold them in place, the boxes are filled with boulders. A video shows the details.
The walls are placed between the pillars and interlock with a connecting system. To prevent them from sinking into the ground due to their great weight, they stand on 30 cm wide stones.
There are two types of pillars, depending on whether they are joined by two or four slabs.
The roof consists of stone beams and slabs. The beams measure 3650 x 200 x 100 mm.
A 25 mm thick screed concrete floor ensures that no rainwater penetrates below. A 10 cm thick layer of broken brick and lime filling follows the weathering course, and a layer of white ceramic tiles (10 mm thick) to reduce heat gain through direct solar radiation is laid on top of the screed.
The roof is accessible via a stone staircase and can be used as a garden.
The building has a footprint of 36′ x 36′ (9.1 m x 9.1 m). It is divided into nine squares, centered on a courtyard and garden, according to traditional Indian architecture.
The house is situated on a plot of 4,000 sq ft (~ 371 m²). The area on the outskirts of the capital city of Bangalore is described as “picturesque.“ It borders the national zoo.
At the rear of the building, there is a pond that collects rainwater and channels it into the community basin. Here, the exterior walls surrounding the property are made of gabions, which promote airflow through the area. They are filled with rubble from the construction.
The project won the “Best Use of Stone Award“ at the 2024 World Architecture Festival. The award was sponsored by the Indian Stone Industry Association (IMIB).
