USE OF NATURAL BUILDING MATERIALS FROM A SUSTAINABILITY PERSPECTIVE
Many of the naturally available and local building materials may not be sustainable in the long run. Dr. Benny Kuriakose discusses about natural building materials such as earth, granite, laterite, lime, timber etc. from a sustainability perspective.
The traditional Kerala architecture, as elsewhere, had developed according to the climate, local materials, and socio-economic relations. Bamboo, earth, lime, timber, leaves etc. were used in the warm humid climate of Kerala.
The most prominent feature of traditional buildings is the sloping roof with 'roof ears'. The carpenters considered the roof design as the most. The important and difficult part. It comes down very low and protects the walls from rain and sun, thus keeping the interior cool.
Illustration 1: A view of the Padmanabhapuram Palace Complex in Kanyakumari District. This is an example of the traditional Kerala Architecture with prominent roofs.
The traditional architecture of Kerala was modest. Houses never attained the brilliance of the places of North India; they were simple, small, but refined. The rich lived in buildings built with laterite blocks, lime, timber and clay tiles. The poorly constructed buildings with less permanent building materials such as earth, bamboo and coconut leaves. But the predominant features are visible in these houses as well.
Natural Materials Vs Local Materials
There is a difference between local materials and natural materials.Traditional Kerala architecture has used local materials. Gandhi ji has said that architecture shall use materials which are available within a radius of five miles.
Natural materials such as marble etc. may not be available locally. They may not be sustainable because of the extra distance in transportation.
In this article, we are looking at some aspects of achieving sustainability to the maximum extent in building construction in Kerala.
In many large buildings, the earth was used. The sun-dried mud bricks may be used for the second storey of a two-storey building, laterite being used for the ground floor. They may also be used for the less important part of buildings. The use of earth blocks (without ramming or sun-dried bricks) was common only among the poor. Mortar using earth is also used in many buildings constructed with laterite so as to reduce the cost of construction.
Mostly, the stone used in Kerala for buildings is granite. We do not have deposits of limestone or sandstone. Granite is very hard and used in the foundations. It was rarely used for the superstructure until the present century, except in temples.
The foundations were usually built with laterite blocks. They are dug out from the earth. Laterite is a hardened earth layer formed due to the weathering of acid rocks. The compressive strength can be higher than that of burnt bricks. It is very porous and cannot hold water. Usually, they are found in layers of 3 to 15 metres below the ground. The top one to two metres will be soft. Towards the bottom, it merges with the clay layer. Laterite can be called the “Blessing of Kerala” since 80% if Kerala’s surface is covered with it. It was widely used for the superstructure. The use of burnt bricks was rare except in the case of few palaces.
Illustration 2: Temple tank in Peralassery Temple in Kannur. The district built with laterite blocks.