Douglas fir is famous in the world for its excellent strength-to-weight ratio. Its high specific gravity provides good nail-holding and fixing power, and is suitable for making wooden frames used in residential houses, small commercial buildings, multi-storey buildings and industrial buildings.
Among North American softwood species, Douglas fir not only has a high modulus of elasticity, but its outermost bending fiber stress, tensile force along the grain, transverse shear force, transverse grain pressure, and longitudinal grain pressure are also extremely good. Because Douglas fir has these physical properties, and has the durability of heartwood and excellent physical stability, many construction companies around the world use Douglas fir as the standard for judging all frame timber.
Douglas Fir is famous for its structural performance, and its appearance is also beautiful. Douglas fir is the most commonly used wood type when the design structure requires large wooden beams, long spans, or arches with special shapes (such as churches, bridges, and gymnasiums). In the construction of residential houses, commercial buildings, public building structures, tower buildings and water facilities, the structural glued laminated beams made by Douglas fir are commonly used as horizontal load-bearing frames for roofs, floors and pillars. When building industrial plants, warehouses, garages, and even building structures with beautiful appearances, glued beams are also reliable building materials.
Douglas fir has a light rose color and a beautiful straight texture, and the color becomes dark after sun exposure. Douglas fir's tough fibers are not easy to cut or sculpt by hand, but as long as you use sharp power tools and machine tools, you can get a smooth cut surface. This wood can be processed into a variety of products along the shape of the grain, the surface is easy to paint, and can maintain various stains and varnishes.
The bark of this tree is thick and split into scales. The leaves are strip-shaped, about 1.5-3 cm long, the ends are blunt or slightly pointed, dark green above, lighter below, with two gray-green stomatal bands. The fruit (cone) of the tree is oval-shaped oval, about 8 cm long, brown and shiny. The seed scales are rhombic or nearly rhomboid, the bract scales are longer than the seed scales, the middle lobes are narrow, long and pointed, and the lobes on both sides are wider and shorter.
Douglas fir enjoys light, warm and humid climate and well-drained acid soil, which can withstand the drought of winter and spring. The bark has a leopard pattern, the heartwood is light red, and the sapwood is light yellow with resin. The material is tough, elastic, and has a long shelf life. Wood can be divided into coastal and inland types. Douglas fir is a good material for construction and appliances. Glued beams are also reliable building materials when building structures with beautiful appearance are required.
Douglas fir can accept various types of dyeing treatment, and its surface treatment materials include transparent paints, transparent paints, varnishes, paints or waxes, and even various dyeing and bright or soft color paints. In order to obtain the best surface treatment effect, the moisture content of the wood should be between 12% and 15%, or the closer to the normal humidity, the better. The outdoor building structure should be coated with a primer first, because Douglas fir is a relatively dense heavy wood.
1. Non-defective timber, processing timber, construction timber and customized timber, etc.
The widespread application of Douglas fir in the construction and secondary processing industries stems from its good physical properties and numerous wood grades. All Douglas fir wood is processed, graded and classified according to relevant domestic or foreign grading standards. According to Canadian classification, Douglas fir wood is divided into:
1) Non-defective materials (no knots): Non-defective materials of grade two and above, non-defective materials of grade three and non-defective materials of grade four.
2) Processing materials (reprocessed into non-defective materials): top-grade processed material board, sub-top-grade processed material board, first-grade and above processed wood material, wood material A and B
3) Architectural use: light frame materials, light structural frame materials, structural railings and plates.
2. Widely used structural materials
Douglas fir has many uses and is a widely used structural material. It is favored by engineers and builders. It is particularly suitable for structural parts and heavy wood structures. It is also widely used in wooden piles and railway sleepers Sawmills, warehouses and countless other areas that focus on structural performance. Douglas fir is a hard and stable wood that can be used to build wooden frames for light and heavy buildings.
Because Douglas fir has high strength and good adhesion, it is often used to make glue beams of various structures, including indoor sports fields, swimming pools, churches and supermarkets.
Douglas fir has a good appearance and is easy to process. It is suitable for processing into window frames and door frames, wooden lines, cabinets and other joinery products. Douglas fir's hardness and strength also increase durability.
Douglas fir has high corrosion resistance and excellent structural properties, so it is also the main wood used to make industrial liquid storage tanks, vats and other storage containers. Its stability and ease of processing also make it the material of choice for manufacturing industrial parts.
3. Use of Douglas fir construction
Because Douglas Fir has a high load bearing capacity and a high weight ratio, the main application in construction engineering is to glue beams and building timber. One of the most extensive is the use of architectural timber. Architectural wood is commonly known as mouth material. Mainly based on 35 * 85 specifications. There are also different specifications according to the geographical division. Among them, Hangzhou is mostly 39 * 89, and there are also 5 * 10 specifications. Sawn board is usually processed into outdoor landscape wood board. The board is treated with anti-corrosion treatment and is the first choice for outdoor wood flooring.
4. Domestic use of Douglas fir conventional size
Large-scale development of domestic real estate, high-rise buildings can be seen everywhere. The more the house is built, the higher the demand for wood and square materials. This has led to a shortage of wood domestic materials, and the import of foreign wood has led to the construction of wood Fang, the size of the project materials are also inconsistent, from the size of the wooden shelf under the house structure template used in 1996 is 50 × 100, 40 × 90 (unit: MM) to today ’s size 32 × 82, 35 × 85, 40 It can be seen from × 60, 40 × 70, 40 × 80, 44 × 64 (unit: MM) that due to the shortage of materials and the increase in prices, the size of the materials has shrunk, leading to inconsistent specifications.
Nowadays, the imported materials have different origins, and the materials are similar. Some of the materials in the origin are fragile, fragile, insufficient gripping force, insufficient weight, and inconsistencies in the size. Available: 35 × 85, 37 × 87, 40 × 90, 45 × 60, 60 × 60, 40 × 70, 40 × 60, 38 × 88, 50 × 70, etc. Length: 2m, 3m, 4m , 2.5 meters, etc.
It is not a commercial building or a residential building. Generally, the flat floor does not use wooden formwork, but a beam floor. The dimensions are: 20 × 250, 20 × 300, 25 × 200, 25 × 250, 23 × 250, 23 × 300, 30 × 250, 30 × 300, etc., length 3 meters, 4 meters.
The general dimensions of engineering sleepers are: 100 × 100, 200 × 200, 300 × 300, 400 × 400, etc., and the length is 2.5 meters, 3 meters, 4 meters.
The general dimensions of the project springboard are: 40 × 250, 40 × 300, 50 × 250, 50 × 300, etc.
The general dimensions of furniture materials are: thickness 18, 20, 23, 25, 30, 45, width 75, 95, 100, 120, 140, 150, 175, 235, etc.