How to Build a Cripple Wall Using Concrete Blocks

A cripple wall is a half-height wall, generally installed in the basement on top of the lower level of a stepped foundation. When the surface of the ground only comes halfway up the wall, the foundation wall is usually built only to a matching height, requiring a cripple wall to reach the rest of the way to the ceiling. Wood cripple walls are notoriously weak, and can be dangerous to the integrity of your home if you live in an area that experiences earthquakes. A concrete block cripple wall, on the other hand, will provide the stability you need.

Portland cement
Water
String and stakes
Bricklayer's trowel
Concrete blocks
Mason's level
Masonry chisel
Bricklayer's hammer

Instructions

- 1
  Mix Portland cement and water to make a mortar for your concrete wall, adjusting ratios until you reach a glue-like consistency. Stake lines along the perimeter of your future cripple wall to determine its exact location.
- 2
  Spread mortar along the top of the foundation wall in one of the corners and lay a concrete corner block on it, aligned with the guide lines and positioning it carefully. Spread more mortar underneath each subsequent block, adding mortar between the blocks as well to give them cohesion. There should be an approximately ⅜-inch section of mortar between every pair of blocks.
- 3
  Check the alignment with a mason's level every five blocks or so, tapping blocks into place whenever you find imperfections.
- 4
  Add subsequent layers of blocks, staggering the blocks for maximum wall strength and continuing to place mortar between every two layers. Use a masonry chisel and bricklayer's hammer to cut blocks in half when necessary at the ends of the wall.
- 5
  Continue building the wall until it reaches its final height. Use concrete screws to secure woodwork to the cripple wall when necessary, as you continue your building project.

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