Concrete blocks, sometimes called cinder blocks, are an inexpensive component of masonry work. Because the blocks are cheap, block walls are generally much less expensive to build than stone or brick walls, but are also usually considered less attractive. However, there are many different types of blocs that can be used to make walls, some of which are quite attractive.
The first thing to consider when building a block wall is what type of blocks you are going to use. Lightweight, or cinder, blocks are much lighter than standard blocks, which weigh about 45 pounds (20.4 kg). Standard blocks are 8 by 8 by 16 inches (20 by 20 by 40 cm) and have plain faces. These blocks are not very attractive but are often used for block walls that will have a stone or brick facing covering up the blocks.
Decorative blocks come in a variety of shapes, sizes, and styles. Some decorative blocks have patterns cast into their faces and can be put together to produce patterns in a block wall. Slump blocks are a type of decorative block that appear irregular and more natural, like adobe or stone. Screen, or grille, blocks form patterned screen walls which provide privacy but allow light to enter. Split-face blocks are broken during manufacturing and resemble cut stone. Finally, glass blocks can be clear, wavy, or patterned, and are usually square.
Block walls can be built by amateurs, and is much quicker than laying brick. Some people add steel reinforcing rods and grout in the hollow core of the blocks to add strength. The same mortar can be used for block walls as in bricklaying. Glass blocks are trickier to install, but skilled amateurs should still be able to construct a glass block wall.
If a block wall is taller than about 3 feet (0.91 m), it may need to be reinforced with steel. Vertical steel rods can be placed in the footing trench of the block wall, extending up through the cores of the blocks. When the block cores are filled with concrete or grout, the steel bars will be fixed in place. Local building authorities can give more information about reinforcement requirements in your area.
If the block wall looks too boring, there are many finishing techniques to make block walls more attractive. Solid cap blocks can be used on the top of a block wall to give a more finished look. A block wall can be simply covered in plastering stucco, or plaster can be mixed with coloring oxides to create a brilliantly colored wall. Bricks or stones can be added to a concrete block wall, giving the appearance of a solid masonry wall, but for a much lower price.
Written by Bronwyn Harris