Tile is a common material used for roofing in civil engineering, which is almost as old as the Chinese civilization, and the original roof tiles were made of clay.
By chance, We found that in the southwest of China, there are still some traditional dwellings with wooden shingle roofs. We couldn't help but wonder how these wooden shingles could break through the characteristic of easy deformation in water and survive the wind, rain and snow for decades without rotting. With such questions, we conducted an in-depth investigation.
Special wooden shingles
While supporting and participating in the Rong Design Library's research on Lacquer and Wood Materials, we learned from Fan Jianjun, a craftsman, that the reason why lacquer products can be used for hundreds or even thousands of years is not only because of the lacquer's protection, but also because of the stability of the embryo, 80% of which is made of wood. At the same time, we visited some ancient buildings in Shanxi and found that their wooden building materials have remained intact for thousands of years.
This prompted us to think about the Chinese traditional way of making wood: Why is it that wood materials made by our modern technology disintegrate naturally after a few hundredyears, whereas ancient buildings in Shanxi and otherplaces use wood made in the traditional way, and theyhave lasted for thousands of years? With this questionin mind, we began our research on "Traditional ChineseMethods of Wood Treatment" under the guidance of“Fan&qiu Lacquerware Research Institute”and Dana Huang.
In the process, we discovered a type of traditional wood-framed dwellings inhabited by ethnic minorities insouthwest China. The shingles of these houses are different from common shingles in that they are made of wood. These shingles laid on the roof have not been processed by any modern technology, but are able to withstand rain, snow and wind.
How do wooden shingles survive rain, snow and wind without rotting?
After the investigation of the traditional “Waban House”, we found that the reason why these wooden shingles can survive the test of wind, rain and snow is related to the local materials and the use of traditional craftsmanship in its making, as well as the smoke it is subjected to in its daily use.
First of all, most of these waban houses are built in patches on mountains or slopes surrounded by forests. With abundant forest resources, the local people will build their houses with local materials.
Similar to the Alishan region, which is capable of producing high-quality hinoki, the Southwest region also has low latitude, high altitude, and abundant light, thus providing good conditions for the growth of high quality fir or red pine. Fir trees are straight, upright, with fewer camphor knots, straight grain, easy to decompose, and have natural oils that can prevent moisture and cracks; red pine wood also has straight grain, and the material is fine and highly resistant to decay.
Secondly, the shingles are made using a traditional way of making wood - the splitting and tearing. This process involves first splitting the harvested wood with a knife and axe perpendicular to the cross-section of the annual rings, and then continuing the splitting and tearing process in a radial direction, allowing the wood to naturally break down along the grain of the wood conduit, thus obtaining a wood shingle with a straight grain. The wood conduit structure of the shingles made in this way is not destroyed, making it difficult for water to penetrate, thus flowing naturally down the wood grain and providing a rain-proof effect.
There is a local saying that "Those people who are treated tough won't make it, those shingles that are chipped out won't be rainproof". If you use industrial methods to make wooden shingles, sawing the wood conduit, the roof will leak when it rains. The traditional way of making wood by cutting and tearing is to reasonably "analyse" the wood and then decompose it, respecting the natural properties of wood, which cannot be replaced by machines.
Finally, the newly laid shingles are generally a lighter log color, and as people built fires in the house to cook their meals daily, the rising smoke from the cooking fires would penetrate the shingles and have a smoky effect on them. This kind of smoking is also one of the traditional methods of drying wood. Unlike modern steam drying, smoking does not destroy the lignin in the wood, but also takes away the excess moisture in the shingles, enhancing their anticorrosive and insect-resistant properties, and allowing the shingles to withstand wind, rain and snow. In addition, the local people will turn the shingles once a year to further extend their service life.
Instead of using nails to hold the shingles in place, the locals put strips of wood or stones on the overlap of the two rows of shingles, or tie them with a rope. This ensures the stability of the shingles and makes it easier to turn them over later.
After shingling both sides of the roof, the shingles on one of the sides near the ridge should stick out more to the other side to block any rainwater that might leak into the ridge.Whenever it rains or snows, water can then flow down the grain of the shingle, creating a natural drainage structure.
The demise and regeneration of wooden shingles
During a study tour in Yunnan, we stumbled upon a small remote village surrounded by walnut trees, where the original Waban Houses remained. Some of these houses still have people living in them, while others are deserted. Looking at this village, which could disappear at any time, we couldn't help but think: with economic development and social change, many of the existing Waban Houses in the Southwest China are about to collapse, fall into disuse, or even die out because they are no longer able to satisfy the functional needs of people's lives today, so where should these high-quality wooden shingles go?
At the same time, due to the protection of forest resources, we can no longer cut down trees at will, so today there are very few large-diameter trees that can be made into shingles of about 50 centimeters. Generally speaking, a fir or red pine tree grows for 60 to 70 years before it "becomes timber" and has a "heart", which can be used for making shingles. When the tree's diameter reaches 50 centimeters or more, it can be made into a shingle board with a width of about 20-30 centimeters. The existing old shingle boards with a diameter of about 50 centimeters are made of large-diameter wood of more than 1.2 meters cut down decades ago, which is more resistant to change and waterproof. Thus, these large-sized old shingles have almost become "out of print".
So, we recycled these large old shingle boards to preserve the possibility of re-use them - either to continue to be used as new architectural shingles or for outdoor walls, fences, fixtures, utensils and more.
Even if the wooden shingles end their mission as roof tiles, their natural vitality and traditional cultural connotations can still be continued through design and reflection.
The Festival of Design opened on November 10, 2023 at 19:00 with the launch of the installation "Primordial" designed by Neri&Hu. The installation used our recycled large wooden shingles and was displayed in a design exhibition with the theme "Re -".
Acknowledgement｜Fan&Qiu Lacquerware Research Institude Dana Huang