Baked for 100 years: clay houses stand tall in northern Vietnam

Modern-day building techniques revolve around bricks and mortar, steel-reinforced concrete and synthetic materials that all point to a future isolated from nature.

But here in Lang Son Province in northern Vietnam, there are still hundreds of houses made of materials that can be found at your feet. Some buildings have even been standing for a few hundred years, and now, besides providing shelter, they offer visitors to the land a chance to get back to nature. They are called ‘nha trinh tuong’, with 'nha' being house and 'tuong' being wall. 'Trinh' is derived from the word 'chinh', which means "pounded until firm" in the language of the Tay and Nung, the ethnic minorities that live here.

The Tay and Nung ethnic minorities in Lang Son created the ‘nha trinh tuong’ using clay mixed with mud that is shaped using frames and pounded to the desired stickiness.
There are two techniques used to make a ‘nha trinh tuong’. The first has walls made directly of clay shaped using a frame. The second one employs a frame to make clay bricks which are then used to build a home the normal way, only with clay mortar instead of cement and sand.

The hardest part though precedes any construction process: choosing where to build. According to the Tay's Feng Shui beliefs, the best houses face south with their backs to the mountains. The obvious indicator for a good lot is to have lots of trees around, ancient trees ideally, because as a rule of thumb, land covered with trees will never erode.
A two-storey ‘nha trinh tuong’ is, well, a different story. The hardest part is reinforcing the foundations and pillars. The foundations are built using only chunks of stone placed tightly on top of each other so they can hold the weight. The pillars at the four corners of the house must be erected by an experienced builder, or expect a collapse.

A good clay house doesn't allow water to penetrate its walls. To achieve that, the clay used to make the walls has to be well prepared, which might take up to three months. Clay houses are warm in the winter and cool in the summer. The only weakness they possess is that mold tends to grow on the walls, but that can be fixed with a wood-burning stove at the center of the house.
Symmetry is part of the architectural philosophy here. All the main doors are decorated with paper talismen or mirrors to ward away evil.

Source Vnexpress, Photos by Luu Minh Dan