Lastulevyn

Lastulevyn is the Finnish term for plywood, an engineered wood panel formed by gluing together multiple thin sheets of wood veneer or plies with alternating grain directions. The layered structure provides increased strength, stiffness, and dimensional stability compared to solid lumber, making it a common material in construction, furniture, and packaging.

Most lastulevyn is produced from softwood or hardwood veneers and bonded with moisture-resistant adhesives such as phenol-formaldehyde. The veneers are laid with alternating grain, stacked, and pressed under heat to form a rigid panel. Typical thicknesses range from about 3 mm to 50 mm, with standard panel sizes often around 1.2 by 2.4 meters in many markets.

Plywood is graded by face quality, core configuration, and moisture resistance. Exterior and marine grades use weather- or water-resistant bonding. Birch plywood is common in Nordic markets for its smooth surface, while cores may include poplar, pine, or other species. The choice of grade and core affects appearance, strength, and suitability for different environments.

Applications include structural elements in roofs and walls, subfloors, cabinetry, furniture, and packaging. Plywood offers good strength-to-weight ratio, impact resistance, and ease of machining, although its performance depends on proper sealing and protection against moisture. Environmental considerations include the use of low-emission resins and forest-certification schemes such as FSC in many markets.

See also: veneer, engineered wood, plywood adhesives.