How to Lay Different Concrete Block Shapes Together

Concrete blocks.
What You'll Need
Concrete for footings
Mortar board

A variety of concrete block shapes are available for a number of applications. Different patterns and architectural effects can be achieved by using the different shapes and sizes of the concrete blocks. Concrete blocks are used as a building material for constructing walls, foundations, and footers. Laying the concrete blocks of different shapes together is not much different from laying those similar in shape. However, the directions below can help when you are dealing with blocks of different shapes.

Step 1 - Choose the Blocks

You must choose the correct blocks according to your needs. Mostly you will need the regular-sized 8-inch-by-16-inch concrete blocks for the bulk of the structure. However, you may require different shapes of the concrete blocks for patterns and specialty blocks for the completion of the course of blocks. When necessary, you can cut the concrete blocks to make them fit the course or to obtain a certain shape. Keep your blocks dry as they expand when they are wet and then shrink upon drying.

Step 2 - Lay Proper Footing

Next, you must build your structure (for example, a wall) on a proper concrete footing. For a strong structure, pour the concrete footing below the freezing point of the area you live in. The footing must be at least twice as wide as the block and twice as deep or as the local codes direct.

Step 3 - Lay the Concrete Blocks

It is important that you build some guidelines for your structure. At each corner, drive stakes of wood and tie a string to them. Now, according to the planned course of blocks, place the stakes in line. Lay the blocks in place for the first row of the course while spacing them with a piece of 3/8-inch plywood. The thickness of the plywood is the same as the thickness of the mortar that will be between the joints. Remember that the wide side of the concrete blocks should face up as it will provide more space for the mortar and will minimize the waste of mortar. It will be easier for you to handle the blocks from the wide side.

Step 4 - Spread the Mortar

You must adjust the different concrete blocks according to the required course. Mix up some amount of the mortar and spread it onto the footing with the help of a trowel. The mortar must be at least 8 inches deep and 3 blocks long. Start with the corner block and ensure that its alignment is perfect. For checking the tops and edges of the blocks, you must use a mason’s level. Build all the corners first and use them as guidelines for other blocks. When you have to lay the different shapes of the blocks together, make sure they fit correctly and are aligned perfectly. Continue laying the blocks according to your pattern and remove the excess mortar with the trowel and throw it onto the mortarboard. Once you are done with the first row, continue to add blocks in the same pattern until your structure is complete.