Story: Phan Cam Thuong
Photos: Son Tung, Nguyen Tuan
Rammed earth houses are cultural treasures in Vietnam’s northern highlands
Many American researchers agree that Southeast Asian civilizations originated in Tibet since most rivers flowed from the Tibetan Plateau, carrying cultural elements infused with local characteristics. As these rivers ran downstream, they gave rise to various civilizations, each with its own set of customs. The Ganges and Indus rivers flow from the Himalayas and formed the Indian civilization, while the Mekong and Red rivers flow from the Himalayan fringes and formed Vietnamese, Lao, Khmer, and Thai civilizations, which merged with the Malayo-Polynesian civilization from the South Sea to create an eclectic cultural mix.
Building houses is the first and most basic sign of all civilizations, since people always feed and house themselves before creating art. Rammed earth constructions are part of the ancient heritage of a vast region that stretches from Tibet, through Yunnan (China), to North Vietnam. Although building techniques have evolved, the fundamental principles remain unchanged.
One example of rammed earth structures are Tibet’s earthen monasteries. Their walls are quite thick and can be built as high as a modern house. The earth walls of the Potala Palace in Lhasa are up to 2.5m thick in some places. They are not entirely made of earth. Large bundles of cogon grass up to two meters in length were placed on the walls and then plastered with earth. The outermost wall can vary from 50cm to 70cm or even 100cm in thickness. Windows could have been carved in as well, but they would have been very small and deep due to the thickness of the walls. Locals then used cloth towels to beat the walls repeatedly, removing all moisture. The result was a hard, glazed, and glossy surface that resembles terracotta. This task was undertaken by young women who sang uplifting folk songs as they repeatedly beat the walls with towels.
Another example of this type of structure are Yunnan’s rammed earth houses. Each house has two rectangular floors: the lower floor for living and the upper floor for the altar and food storage. People usually added a window or a balcony on the upstairs wall of the middle compartment, where corn was hung to dry. However, in Yunnan (particularly from Kunming to Dali and Lijiang), rammed earth houses on hillsides were frequently clustered into villages of a few dozen to a hundred houses. There is almost no space between these houses, which were built next to each other, creating a seemingly stacked row of houses along the hillside. These villages contain complicated networks of small lanes, allowing people to climb from one house to another. This type of defensive village layout was designed back in the days when ferocious bandits roamed this region. If strangers entered the village, they were very unlikely to escape.
Aside from the stilt houses of Muong, Thai, and Tay people, detached rammed earth houses are common in Vietnam’s northern mountainous region. There are virtually no defensive villages like those in Yunnan, but there are defensive detached rammed earth houses. These houses were built with two layers of walls: an inner layer for the main house where people live and an outer layer separated from the inner layer by a corridor. A second-floor deck was built around these houses as a place for the owners to stand and shoot flintlock rifles through small doorways. Between the outer layer and inner layer lay numerous solid compartments from which to repel small groups of bandits. This type of house was typically built by wealthy Tay and Nung people.
Building a rammed earth house requires a Kay, a type of wooden formwork with two sturdy panels that are two meters long and 40cm wide. Two more boards can be added at both ends to form a bottomless, lidless mold. There are holes on the sides through which iron bars are pierced to keep the long panels stable when the earth is compacted. After the wall is beaten, builders extract the iron bars and remove the Kay to repeat the process on another section. Kay-building has long been popular among H’Mong, Dao, and Kinh ethnic groups in Bac Giang province. Meanwhile, Lang Son’s rammed earth houses do not require a Kay; rather, builders use bamboo to create a simple mold for compacting the earthen walls. Another option is to make the soil into bricks for house-building. All techniques depend on the quality of the local soil. Ha Giang and Lao Cai have similar types of soil. In contrast, as the soil in Loc Binh – Lang Son is rich in clay and sand, the walls are usually reinforced with bamboo, while the foot of the wall is covered with a thin layer of stones to prevent erosion and landslides.
The places where these houses are built tend to be cold in the winter and hot in the summer, making rammed earth houses the most “environmentally friendly” option. These houses stay warm in the winter and cool in the summer. They are also built using free local materials. Building rammed earth houses requires builders with both exceptional skills in traditional crafts and a willingness to contribute to the community. Wooden frames are also used to ensure the structural integrity of the earthen walls and columns.
The rammed earth houses in Loc Binh, Lang Son reveal the prosperity of Nung Phan S’linh and Tay households, especially in Khieng village (Huu Thang commune). The main houses are large, two-story buildings constructed on plots of land up to 200m2. Each house’s walls are only about 40cm thick, while the base of the walls is covered with stone slabs. Furthermore, there is usually a large corridor between the two layers of the back wall. Because the house typically faces north, cold northern air must pass through both layers of walls to reach the house. This back corridor has a path that leads to one side of the auxiliary room, which is frequently used as a kitchen. The kitchen has a separate exterior entrance and is directly adjacent to another row of rammed earth houses that store sheds for farm equipment, cattle stalls, and poultry cages. The last house is used as the toilet. This typical house layout in Loc Binh saves a lot of space and can be built up into multiple stories. It is less reliant on a thick soil structure than other types of rammed earth buildings.
The emergence of new materials is not the sole reason for the decline of rammed earth houses. The main reason is that builders skilled in this craft are gradually disappearing. Sourcing the necessary soil is getting harder as available private land is shrinking while public land-use is strictly managed. Furthermore, not all kinds of soil are suitable for building these traditional houses. As a result, the remaining rammed earth houses are living heritages and distinctive cultural features of the highlands.