How to Add to the Top of a Block Wall

Durable block walls require little maintenance once installed, so they are favored for areas where a permanent wall is desired. Making a short wall taller requires minimal skill since the complicated part of leveling the original wall has already been accomplished. Add tiers of blocks to an existing wall on a dry day so the adhesive can cure properly. Removing any debris or dirt from the top of the old wall further ensures that the new blocks attach securely.

Chalk
Masonry saw
Masonry construction adhesive
Caulking gun

Instructions

- 1
  Determine the block arrangement for the new layer. If the existing wall begins with a whole block, the new line must begin with a half block so the joints are staggered between layers. Start with a whole block if the existing top layer begins with a half block.
- 2
  Cut the end blocks in half before you begin laying the wall, if applicable. Mark the center of the wall block with a piece of chalk. Continue the chalk line around the block, so the center is marked on four sides. Cut the block in half along the marked line, using a masonry saw.
- 3
  Insert a tube of masonry construction adhesive into a caulk gun.
- 4
  Apply two lines of adhesive to the top of the existing wall. Place each line 1 inch in from the side. Apply the adhesive to the top of four to five blocks at a time.
- 5
  Set the new blocks on top the adhesive, beginning with a half block if necessary. Arrange the blocks so they sit flush against each other and so their joints are staggered above the joints of the layer of blocks beneath.
- 6
  Continue applying adhesive and adding new blocks until you reach the end of the wall. Add additional layers of blocks to the wall using the same method.

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