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Types Of Concrete Blocks
When building walls, blocks and bricks are primary materials. Bricks are smaller and made of clay, although concrete bricks are also available. Blocks are bigger, made of concrete aggregates only and can be categorized as either masonry or fair face.
There are two types of masonry concrete blocks. Solid masonry blocks have rough, unfinished surfaces and require plaster and paint of proper finish. These vary in strength from 600 to 800 pounds per square inch (psi) and 1,000 to 1,200 psi. The usual sizes include: 4"x 8"x 12", 5"x 8"x 12" and 8"x 8"x12".
Hollow blocks are used for exterior south walls (facing the sun) as the cavity within. The block decreases heat gain. The hollowness of the block decreases he weight bearing. Capacity of the wall and they should not be used for load bearing purposes. Sizes include 4" x 8"x 12", 5"x 8"x12" and 8"x 8" x 12".
The two types of fair face blocks are solid and cellular. Solid blocks are steam cured, have a finish and smooth surface that do not require plaster or paint. Available in natural, grey finish and pigmented finish in terracotta, yellow and mud colours, they come in two sizes: 4"x 8"x 16"and 6"x 8"x 16".
Cellular blocks have a cavity and offers the same function as masonry hollow blocks; they are available in here sizes: 4"x 8"x 16", 6"x 8"x 16"and 8"x 8"x16".
When selecting which block to use, consider the following:
- For load bearing use a thick block. For an external south wall use hollow blocks as they provide insulation against the heat. For a concealed electrical or plumbing line, do not use hollow or thin blocks.
- Commercial buildings have different requirements to those required for houses. Block size and thickness depends on the space restrictions and load bearing requirements.
- For a finish look devoid of paint, use fair face blocks. For better quality in terms of strength and durability, choose branded blocks although they are mare expensive than unbranded blocks.