How to build retaining walls with concrete block

The concrete masonry units (CMUs) are available in various sizes and are an effective, permanent means of building structures under maintenance. The design base of a retaining wall made ​​of concrete blocks depends on concrete Cement discharges, known as “base”, which defines the level of basis of the structure above the concrete block wall. The basic procedure for installing a single containment wall of concrete blocks can be adapted to a wall of any length and height.


  1. Install a poured concrete foundation for the retaining wall. The base must be at least 12 inches wide and 8 inches deep and constantly leveled the entire length of the embankment. You must leave the base hardens at least 48 hours before starting the construction of the concrete wall. The base is placed on the floor unchanged.
  2. To remove dirt thoroughly cleans the top surface of the base with a broom.
    Defines the line from the wall to the concrete blocks with a hammer nailing, wood or steel stakes at each end of the location of the retaining wall, located approximately 3 feet beyond the ends of the wall, Make sure the stakes are vertical and enough to firmly hold that depth.
  3. Place a piece of nylon rope between two stakes as guide to the wall. Adjust the stakes as necessary to align the guide with the desired outer face of the retaining wall. Be sure to keep it tight and unobstructed. This will be used as a vertical guide for laying concrete blocks.
  4. Levels below the guideline established in step 4 and perform a vertical mark on the guide line of the upper surface of the base of the retaining wall at both ends of the wall. Use chalk lines to mark a line connecting the two brands. This establishes a line of the wall of the first layer, referred to as “spun”, a concrete block.
  5. Mixing a quantity of mortar premix, also known as “grout” in a box or mortar mix truck according to the manufacturer’s instructions and recommendations for the length of the first course of concrete blocks, the consistency of concrete should be moist and similar to peanut butter.
  6. Starts at either end of the retaining wall and establishes a line of concrete along the sidewall of the chalk line made in step 5 of about 1 1/2 inches wide, 3/4 inch thick and 2 feet long. With a palette, Place a second parallel line of 8 inches of concrete identical to the first.
  7. Slowly placed in the concrete block and mortar lines novella drop a level, Hits gently with the handle of the palette or a rubber mallet, and leveling the top as needed, making sure to maintain a line of mortar least 3/8 inch below it. Also make sure the end of the block is aligned with the desired end of the retaining wall and the outer edge is aligned with the chalk line. Use the trowel to collect the excess concrete that is poured down the block and return it to the mixture for reuse.
  8. Check with a pallet, two lines of mortar along the sidewall of the chalk line for the next block, again about 1 1/2 inches wide, 3/4 inch thick, 2 feet long and 8 inches apart. Place the next block down gently on the mortar and making sure that it is level and tight adjacent edges.
  9. Repeat step 9 for each concrete block and the rest of the first course of the wall. When the row is complete, it is good idea to check the alignment of each block with the guidelines of the wall and each has maintained its level.
  10. Return to the starting point of the first row of concrete blocks and start the second course. With a palette, make two lines of mortar along the top edge of the first block, again about 3/4 inch thick and 2 feet long.
  11. Put in place the first block of concrete, then gently tapped the top of it with the handle of the palette or a rubber mallet, as necessary, to level. Note: Begin the second course (and all others) concrete block with “halves” 8x8x8 block to compensate for the vertical joints 8 inches the previous row.
  12. Repeat steps 10, 11 and 12 to complete the installation of concrete blocks for a retaining wall.
  13. Wait at least 24 hours before filling the cells of the blocks to allow them to set mortar joints.
  14. Full concrete block retaining wall with concrete standard to maximize, if necessary, the strength of the wall. To give a final touch, you can cover the full containment wall with 2×8 concrete lids secured with mortar.
  15. Allowed to set full containment wall for 48 hours at least before backfilling with soil or rocks.

Tips & Warnings

  • For ease of installation, try to plan the size of your retaining wall to match the standard size of 8×16 inch blocks to minimize the need for cutting. For walls over 32 inches tall, you should consult with an engineer for advice in relation to the size of the base and other structural considerations.
  • To add strength to your retaining wall, though in many places it is not a requirement, you can consider adding some horizontal bars of 1/2 inch reinforced steel, each 24 inches.
  • Local and state codes, and national construction, have specific requirements regarding the size of the foundations and retaining walls concrete blocks, and you should contact the local office building to verify your compliance plans retaining wall.