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How to Build a Concrete Block Wall

Mayuri Kulkarni Jun 30, 2019
Building a concrete block wall is not as difficult as it appears to be. Here's a simple step-by-step guide that will help you learn how to build one yourself. Have a look!
A concrete block wall, as the name suggests, is nothing but a wall made by stacking blocks of concrete one above the other. While it's a fact that you can build a concrete block wall yourself, you should know the steps before you start building one.
Also, you need to keep a few things in mind in order to be successful in your endeavor. Wondering what they are? Well, all you need to do is just read ahead to find out ...

Steps to Build a Concrete Block Wall

For constructing a concrete block wall, it is necessary to decide the type of concrete blocks that you will be using. There are many types of concrete blocks used in different constructions, such as stretchers, end blocks, rough edged blocks, cap blocks, decorative blocks, and interlocking blocks. Choose the one that best suits your requirement.
First measure the area of installation and then purchase the required number of blocks. Also, estimate the amount of mortar required and purchase accordingly. Before we move on to the steps, let us take a quick glance at the list of equipment and materials needed for building a concrete block wall.
Equipment Required:
  • Measuring tape
  • Shovel
  • Hammer
  • Steel square
  • Corner poles
  • Mortar board
  • Masonry Trowel
  • Jointer
  • Straightedge
Materials Required:
  • Mason's string
  • Lumber
  • Reinforcement bars
  • Plastic sheet
  • Line chalk
  • Nails
  • Wooden strips (3/8" thick)

Step 1: Laying the Foundation

Prepare an outline of the wall and wall footing with the help of the masonry string. Level the area where you'll be installing the wall. Then, dig the foundation required for the wall; the width and depth of the foundation should be twice the width of the wall.
Prepare a wooden frame using lumber around the strings, and install reinforcement bars to ensure strength of the footing. Fill the frame with concrete and level it throughout. Then, leave the concrete to cure for at least 3 days by covering it with a plastic sheet. Your foundation is ready.

Step 2: Drawing the Outline

⇒ Look at the construction drawing carefully and note the exact dimensions for the elevation and floor plans. Also, note the exact position of the openings for doors and windows.

⇒ Mark the corners as per the measurements given on the drawings, and transfer them accurately on the foundation.
Once you've marked the exact position of the two corners, a chalk line needs to be drawn across them. A chalk line is nothing but a straight line on which the concrete blocks will be placed.
Using the hammer and nails, mark points along the chalk line, so that the line can be redrawn, in case it fades away or gets wiped out.

As you draw the chalk line across two adjacent corners, don't forget to mark the position of the doors and other openings.

Step 3: Trial Run

This step is crucial before you actually begin laying the blocks. Choose any corner and start placing the blocks one beside the other, without the use of mortar.
The main purpose of this step is to allow you to check how the first level of block looks like, and whether it turns out exactly as it should, according to the floor plan. Also, you can determine how many blocks, if any, need to be cut.
The thickness of the mortar joints between two subsequent blocks should be 3/8", and this thickness should be taken into account while placing the blocks. For this, you can use wooden strips that are 3/8" thick, and place one between each pair of blocks.

When you're done, the next step is to mark the exact location of the corners, using a steel square.

Step 4: Setting up the Corner Poles

Begin with the corners when you start laying the first level of concrete blocks using mortar. This is because perfect corners make perfect walls.
To make things easier for you, there's something called a corner pole. All you need to do, is get two such poles and fix them at two adjacent corners. The poles come in various lengths, and you can choose one as per the height of the wall that you intend to build.
Now, that you have the corner poles fixed, draw markings along the length of each pole at a distance equal to the height of the blocks you intend to use. However, make sure that the markings coincide on both the poles. (For example, the 5th marking on one pole should be exactly on the same level as the 5th marking on the other pole.)

Step 5: Laying the Blocks

Take mortar in the mortar board and spread it on the foundation, using a trowel, such that, the layer of mortar is about an inch in thickness.
Begin with the corner blocks. Take the first corner block and place it on the exact spot marked beforehand. Make sure that the thickness of the layer of mortar between the block and the foundation is 3/8". Now, place the corner blocks for the other three corners in a similar manner.
Once you're done, keep on placing the blocks one beside the other, while removing the excess mortar with the trowel.

Proceed in a similar manner for the remaining rows, spreading a layer of mortar on the upper surface of the blocks as well.
Do not place a block exactly above the block below it. Instead, place the blocks as shown in the image. This pattern of laying the blocks strengthens the wall.

After each layer of blocks is laid, shift the mason's string to the next marking on the corner pole. This way, you can check the level of each layer as you go upwards.

Step 6: Finishing Touches

Use the jointer to scrape off any excess mortar from the joints, for smoothening the ragged edges.

Check for any gaps between the blocks. If you find any, fill them with a fresh layer of mortar.
Check the level of the top layer using a straightedge. If it is slightly uneven, use a jointer to smoothen the uneven spots.

⇒ If you find traces of mortar anywhere on the surface of the wall, scrape it off using the trowel.