The Ultimate Review of Man-Made Panels and Engineered Wood (Part 2)

CLT

Originating in Europe, CLT is a cutting-edge engineered timber building material. It's constructed from cross-laminated, glued-together timber panels. The area and thickness can be customized, and its high strength allows it to replace concrete. It's earthquake-resistant, fire-resistant, and more environmentally friendly than concrete in terms of carbon emissions. Large pieces of CLT can be directly cut and used as exterior walls, floor slabs, and other structures, significantly improving construction efficiency. Currently in the domestic market, it holds a promising long-term market outlook.

I. GLT glued laminated timber

Glued-laminated beams, also known as glued-laminated columns, are constructed from multiple layers of wood laminated together. They're primarily used in the beam-and-column structures of larger wooden buildings. Their load-bearing capacity approaches that of steel beams, but they're lighter, more fire-resistant, and more shock-resistant. (The consensus in modern structural design is that wood is more fire-resistant than steel. This is because steel, once softened, quickly loses its load-bearing capacity and collapses, while wood only slowly chars its surface, forming a protective layer that maintains a certain load capacity.) They're also more shock-resistant. (Wood's elastic structure remains stable despite shaking, while steel's rigid connections will fracture and collapse under shaking, and the survival rate for those struck by wood is much higher.)

The individual pieces of wood before glulam assembly are called lamstock. In many cases, each piece must be strength tested and classified to ensure the bearing capacity of the finished glulam.

J. Composite beam (NLT)

It is easy to be confused with the glued beams mentioned above. NLT is a vertical row of timber, with force coming from the side. The timber is connected with nails, but they do not play a major role from the perspective of force.

K. TJI

"TJI" was originally a registered trademark of Weyerhaeuser Company for I-joist. It is now commonly used to refer to I-joist. I-joist is the English "pictograph", and there is also a corresponding "pictograph" in Chinese - I-beam, or "I-shaped wooden grille".

Mainly used to support floor slabs. This material has replaced most traditional 2x12 in North American wood-frame buildings;

Because: 1) the performance is more stable 2) the thermal expansion and contraction performance is better, which means the possibility of cracks on the edges and creaking in the floor after renovation is reduced 3) it is easier to install and arrange wiring and pipes 4) because it is an engineered wood product, it can be made into a larger span and longer length;

Of course, TJI also has disadvantages compared to 2x12: 1) slightly more expensive 2) slightly worse fire resistance 3) slightly worse sound insulation.

L. Parallel Laminated Timber (PSL)

PSL is made by creating single sheets from Douglas fir, southern pine, or boxwood, drying and gluing them together before using a microwave process to press them. This creates a material several times stronger than raw wood panels and can be produced in lengths of 20-30 meters (common products are 18 meters). This allows for a much simpler and more efficient use of components when designing for large spans, compared to other materials. Its rugged, industrial and postmodern styles are also highly sought after by many designers.

M. Laminated veneer lumber (LVL)

It is also called Microllam, and Microllam is also a trademark of WeHao.

LVL generally refers to engineered wood made by mechanically pressing multiple layers of veneer together in parallel;

Note: LVL is mainly used in wooden structure buildings. The veneers are in the same direction along the grain. It is made of pine wood with waterproof phenolic glue, which is formaldehyde-free. It emphasizes strength, waterproofness, and anti-corrosion properties, and has no requirements for the surface. The plywood veneers are in staggered directions, have certain requirements for the surface, and use urea-formaldehyde glue.

N. LSL Laminated Laminated Timber

LSL cuts logs into long strips, dries them, and then stacks the strips together with parallel grains using high-quality resin. Using a steam spray process, the strips are made into standard boards under the action of adhesives and high pressure. They are mainly used as lintels, head grilles and frame walls.