What are the commonly used specifications of engineering timber in construction?

The most commonly used timber specifications in construction are:

30*50 mm, which is what we often call 35 square meters, is mainly used for hanging ceilings or making some internal structures.

60*90 mm. This specification is rarely seen nowadays. In the past, it was mainly used to make products such as furniture.

120*40 mm, this is what we often call the door edge square, which is often used as the door frame.

In recent years, the real estate has been developed on a large scale in China, and high-rise buildings can be seen everywhere. The houses are getting taller and taller, and the demand for construction wood and materials is increasing, which has led to a shortage of wood materials in my country. The import of foreign wood has led to the inconsistent sizes of construction wood and materials used in China. The sizes of the wooden frames under the house structure templates in 1996 were 50×100 and 40×90 (unit: MM) to today's sizes of 30×70, 32×82, 35×85, 40×60, 40×70, 40×80, and 44×64 (unit: MM). It can be seen that due to the shortage of materials and the rise in prices, the size of materials has been reduced, leading to inconsistent specifications and models.

Nowadays, imported materials come from different places and have similar materials. The materials from some places are fragile, easy to break, lack of grip and weight, and the resulting inconsistency in size is also very obvious. However, in general, the conventional sizes on the market are: 35×85, 37×87, 40×90, 45×60, 60×60, 40×70, 40×60, 38×88, 50×70, etc., and the lengths are: 2 meters, 2.1 meters, 3 meters, 4 meters, 2.5 meters, etc.

It is not a commercial building or a residential building. Generally, flat buildings do not use wooden formwork, but beam bottom plates. The sizes are: 20×250, 20×300, 25×200, 25×250, 23×250, 23×300, 30×250, 30×300, etc., with lengths of 3 meters and 4 meters.

The general sizes of engineering sleepers are: 100×100, 200×200, 300×300, 400×400, etc., and the lengths are 2.5 meters, 3 meters, and 4 meters.

The general sizes of engineering springboards are: 40×250, 40×300, 50×250, 50×300, etc.

The sizes of furniture materials are: thickness 18, 20, 23, 25, 30, 45, width 75, 95, 100, 120, 140, 150, 175, 235, etc.

The sizes of engineering wood used in construction are: 40*75*4000, 45*90*4000, and 50*100*4000. The overall thickness is between 40-50, the width is generally between 75-100, and the length is basically four meters. Depending on the price, the thickness and width are different. The actual measured size varies. There is no specified standard. The key is to see if it can be used for a project.