Building Materials, Third Edition

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™ IQS

4.1.1 Length + 6 mm

• 0mm
  4.1.2 Width + 3 mm


• 0 mm
  4.1.3 Thickness
  Less than 6 mm ± 10 percent
  6 mm and above ± 5 percent
  4.2 Edge Straightness—2 mm per 1000 mm
  4.3 Squareness—2 mm per 1000 mm

The grades and types of block boards are represented as:
sgyw s  2 —2™ ™—2
shig s  2 —2™ —2
ˆgyw i3  2 —2™ ™—2
ˆhig i3  2 —2™ —2
These are further subgraded as Grade I and Grade 2. Grade I is exterior grade used for bus
bodies, railways coaches, prefabricated houses, etc. and Grade 2 is interior grade used for
furniture, partition, panelling, ceiling, etc.

…X These are extensively used for construction of railways carriages, bodies of buses,
marine and river crafts, partitions, furniture, etc.

Batten Boards and Lamin Boards: Batten boards have core made up of 80 mm wide wood
pieces as shown in Fig. 4.27, forming a slab glued between at least two surface veneers.
Whereas, Lamin boards have a core of strips, each not exceeding 7 mm in thickness as shown
in Fig. 4.28, glued together to form a slab which in turn is glued between two or more outer
veneers. The directions of the grains of the core block run at right angles to that of the adjacent
outer veneers.

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In modern building practice, wood is extensively used for walls and floors of buildings,
carpentry and graded plank items, as well as prefabricated standard wooden cottages. A great
quantity of wood is consumed in building and installation work for making piles, poles,
various load-bearing components formworks, scaffolds, etc.