What is glulam? What is the difference between glulam and finger-jointed boards?

Glued laminated wood:

Glued Laminated Timber (Glulam) is one of the three main types of engineered timber, along with wooden I-beams and laminated veneer lumber. Glulam, sometimes also called finger-jointed timber, can be coated with wood wax to prevent deformation.

Glulam production process

Glulam is made of small-diameter materials. It is made into wood with a certain width, thickness and length through a series of processes such as cutting logs into boards, drying the boards, making them into square strips, cutting, selecting materials, finger-joining, splicing, and subsequent processing.

(1) Log processing into boards: Logs are cut into boards by sports car band saws, main small band saws, etc.

(2) Board drying: It is mainly done by fumigating the wood to remove moisture and oil (mainly pine oil in pine wood). Small-diameter wood is prone to cracking and deformation, so after drying and dehydration, the thickness naturally decreases and cracking occurs.

(3) Board processing: After the board is dried, it is planed on both sides by double-sided planing, flat planing, or pressure planing. Then, the planed board is cut into strips by a multi-blade saw.

(4) Material selection and cutting: Screen the cut wood strips and select the wood strips without missing materials, blue changes, oil lines, cracks and knots, and cut them into lengths of 200-700 mm or less.

(5) Finger jointing: The prepared wooden strips are sparsely toothed and then joined into strips using adhesive.

(6) Planing on all four sides: Planing on all four sides will make the joined wood strips into neat square strips.

(7) Paneling: The square strips of specified specifications are pressed into the required panels by a press.

(8) Planing and sanding: Plane and sand the pressed boards to the required thickness.

(9) Repair, sorting and packaging.

Specific applications of glulam

Glulam doesn't alter the structure and characteristics of wood; it remains a natural substrate like wood. However, its physical and mechanical properties surpass those of solid wood in both tensile and compressive strength, and its material quality is also more uniform. Therefore, Glulam can replace solid wood in a variety of applications.

Developed with the increasing demand for long and large structural components in the construction industry, it is mainly used in wooden structural beams of buildings such as gymnasiums, concert halls, factories, warehouses, etc. Among them, three-hinged arch beams are the most commonly used, which was impossible to achieve in previous wooden structures.

In terms of furniture, integrated timber is used in the furniture manufacturing industry in the form of integrated panels, integrated square timber and integrated curved timber.

Integrated panels are used for large-scale components such as table panels, cabinet side panels, top and bottom panels, non-exposed components such as cabinet partitions, bottom panels and drawer bottom panels, and small-scale components such as drawer panels, side panels, bottom panels, and cabinet doors.

Integrated square lumber is used in brackets for tables and chairs, tripods for cabinets and other square or circular cross-section parts.

Integrated bent materials are used in curved parts such as chair frames, armrests, backrests, sofas, coffee tables, etc.

In the application of interior decoration, integrated wood is used as interior decoration material in the form of integrated boards and integrated square materials.

Integrated panels are used for materials such as stair side panels, treads, floors and wall decorative panels.

Integrated square materials are used for beams, columns, decorative columns, stair railings and decorative strips of interior doors, windows and cabinets.

Glulam Troubleshooting

Are glulam, finger-jointed boards and straight-jointed boards solid wood boards?

Many people have asked this question. Finger-jointed boards are essentially the same material, just with an unregulated name. According to national standards, finger-jointed boards are considered pure solid wood, but the method of splicing differs from traditional plywood. Finger-jointed boards are made by joining small pieces of wood together using large machines and glue, resulting in no pollution or toxic substances. Disadvantages: Finger-joints are messy and unsightly, and their mechanical properties are inferior to straight-jointed boards. However, they may experience less deformation, and since panel furniture can be made directly without further processing, they require less labor and are therefore less expensive. The most distinctive feature of finger-jointed boards is the vertical splicing of small pieces of solid wood, with a WWW-shaped interface.

What is the difference between integrated wood and finger-jointed boards?

The relationship between finger-jointed boards and glulam is inclusive, and finger-jointed boards are a type of glulam. However, glulam products in daily life are basically finger-jointed board products, so finger-jointed boards and glulam refer to the same product.

Which type of furniture is better made from glulam? Is glulam furniture pure solid wood furniture?

Glulam is suitable for furniture with multiple panels, such as wardrobes and box beds. It is also an important auxiliary material for mortise and tenon furniture. For example, a dining table is typically made of solid wood for the legs and glulam for the tabletop, effectively combining the two materials. For mortise and tenon frame structures, such as wardrobes, the side panels embedded within the solid wood frame are also often made of glulam, creating cost-effective solid wood furniture. Cabinet doors and tabletops can also be made of pure solid wood panels, which will show better paint resistance, but the cost will be higher. Furniture made entirely of glulam is still considered pure solid wood furniture.

Is glulam environmentally friendly?

The problem of integrated wood has been discussed. It is pure solid wood and is a typical industrially produced solid wood board. It is generally bonded with plywood glue. There are volatile gases in the production process, but after stabilization, it is an ideal board with almost no pollution.

It can be said responsibly that integrated wood is an environmentally friendly material. Some businesses promote the title of formaldehyde-free integrated wood. In fact, most integrated wood is formaldehyde-free and no special explanation is needed.

What are the quality standards of glulam?

Specification for radiata pine glued timber

(1) The panels supplied shall comply with New Zealand Standard 3631:1988.

(2) The units of measurement for the supply of panels in accordance with New Zealand Standard 3631:1988 are cubic metres and millimetres.

(3) With reference to clause 2.3.4.5 of New Zealand Standard 3631:1988, drying defects such as hook bends, S-shaped bends, concave bends, end cracks, etc. may be restricted or permitted.

(4) Drying refers to drying the wood at 70-95 degrees to achieve a moisture content of 8-12% when shipping.

(5) The following wood defects are not allowed or restricted:

★Blue discoloration (a certain amount of mildew on the surface, but not leading to blue discoloration, is acceptable);

★ Dry spots (if there are no obvious spots after 2mm of surface is planed, it is acceptable);

★Gaps are not allowed (unless mentioned in the RW by WWPA);

★The end cracks and cracks are minimal (no more than 50MM);

★Excessive surface cracks and internal cracks;

★Excessive resin content makes wood finishing difficult;

★The volume of undersized lumber in each package shall not exceed 5%. Undersized lumber is defined as lumber that is less than 5% of the lumber value specified on the invoice at the center 1/3 of the lumber's center.

Please note: Cutting grade is based on the percentage of clear wood between defects only, there is no restriction on defect size.

(6) Target standards for centerless material grades: 5-10% for grade 1 cutting materials, 20-30% for grade 2 cutting materials, and 55-65% for grade 3 cutting materials.

Glulam is constructed entirely from short, solid wood blocks, processed through processes such as serration and gluing. Before gluing, the Glulam is cleaned of knots, rot, and other wood defects, effectively reducing the defect rate of the finished product. Furthermore, the Glulam is thoroughly dried, ensuring a uniform moisture content across even large, long sections. Compared to solid wood, it exhibits less cracking and deformation, ensuring consistent, superior product quality.