Softwoods like pine take less time to grow than hardwoods like oak, so they are a more sustainable option. However, untreated softwood is susceptible to rot and mold, so it is typically not used outdoors. Well, that’s about to change. In this video, we’re going to understand how ancient Japanese techniques modify the components of wood to make them stronger and resistant to decay.
Link to my Patreon page: / belinda_carr
CHAPTERS
0:00 Introduction
0:44 Wood cells
1:41 Yakisugi
2:50 Thermowood
4:17 Advantages
5:53 Disadvantages
7:03 Conclusion
Wood fibers are composed of several layers called cell walls. The 3 main components of a wood cell wall are similar to those of CMU block wall
Cellulose is like a concrete block. It is an important structural component.
Hemicellulose is like the mortar, it is a supportive matrix that strengthens the cell wall. Lignin is like rebar. It is a mechanical support that provides resistance to stresses
Moisture is responsible for the expansion and contraction of wood. It exists in 2 forms: free and bound water.
Yakisugi is an ancient Japanese architectural technique that was used to preserve Japanese cedar or Sugi wood. This process of slightly charring the surface of the wood without burning the whole piece is called carbonization. It neutralizes the cellulose or carbohydrates in the wood which is a source of food. This makes it undesirable to termites, fungus, bacteria and pests. It is water-proof, fire-retardant and resistant to rot. It can last over 100 years with no intervention.
Unfortunately this method was forgotten when cheaper wood alternatives flooded the international market. In the 1990s, the VTT Technical Research Center of Finland, developed a new method of preserving wood, based on the Yakisugi method. They called it “Thermally modified wood” or ThermoWood. It is a 3 stage kiln process that uses only heat and steam.
In phase 1, carefully selected dried wood with a moisture content of 12% is placed in a kiln. It is heated to 100-150 C for 48 hours. In phase 2, the temperature in the kiln is rapidly increased to 180-240C and plateaus for 4 hours. In phase 3, the temperature inside the kiln is decreased and steam is pumped in. This helps cool the wood and increase the moisture content of the planks to improve stability. Average moisture after this phase is 4-5%.
This product has plenty of advantages.
It is one of the most natural ways to extend the life of wood products.
It is free of chemicals, so its more sustainable than traditionally treated lumber
The wood is gorgeous. It has a consistent dark appearance throughout, not just on the surface. It looks a little like caramelized sugar.
Because the hydroxyl groups in the cells are decreased, it is water repellent.
It is also fire resistant.
It is dimensionally stable. It doesn’t expand or contract much, it doesn’t warp or cup
Because the natural acids and sugars are affected in the kiln, the wood is not a food source and is resistant to rot and mold.
It is lightweight because of its low moisture content. In fact, it is significantly lighter than the greenish, pressure-treated outdoor lumber.
It is maintenance free.
It has a long lifespan of 20-30 years.
We can use cheap, rapidly renewable pine wood to make long-lasting, outdoor rated products.
Now, the disadvantages of thermowood.
Thermal degradation & a lower moisture content makes it brittle.
It is more expensive than untreated softwood, but around the same price as hardwoods, at least before the blip in lumber prices.
It is not structurally sound and cannot come in contact with the ground.
Some adhesives that rely on soaking into wood fibers to bond, may also not work.
Because the wood goes through a lot of stress in the kiln, you must use premium grade planks without large knots.
The wood shrinks about 5-10%, most of the loss of wood is from milling and machining
--------------------
SOURCES:
• We are Arbor Wood Co.
www.youtube. com/watch?v=rzVoBog8A_4
• Thermalwood Canada - ...
• Americana Real Wood & ...
• Production of Lunawood...
--------------------
Fluffy by Smith The Mister smiththemister.bandcamp.com
Smith The Mister bit.ly/Smith-The-Mister-YT
Free Download / Stream: bit.ly/stm-fluffy
Music promoted by Audio Library • Fluffy - Smith The Mis...
---------------------
Disclaimer: This video was created for educational/informational purposes and qualifies as Fair Use. If you are the creator or own the footage featured in this video and have reservations please notify me via RU-vid comments or email and I will accommodate you
#yakiusugi #japanesewood #sustainability #wood #woodconstruction
12 июл 2024
