How do I attach cinder blocks to concrete slab?

Brenda Miles
by Brenda Miles

How do I attach cinder blocks to concrete slab?

  5 answers
  • Mogie Mogie on Mar 02, 2019

    Step 1

    Set out the first row of cinder blocks without mortar, and adjust and move your wall as needed until you are satisfied with the layout. Draw an outline of the wall on the concrete with chalk, and then remove the blocks.

    Step 2

    Mix the mortar according to the directions on the package. Mix the mortar until it has the same consistency as toothpaste.

    Step 3

    Fill a mortar board with mortar. Pick up a small amount of mortar with a trowel and place the tip of the trowel on the concrete. Move the trowel backward while twisting the it 180 degrees to spread the mortar onto the foundation. Place a 1-inch-thick bed of mortar along the concrete foundation.

    Step 4

    Set the first cinder block firmly into the mortar. Press down until the mortar joint is 3/8 inch. Spread a vertical bead of mortar along the side of the block with a trowel.

    Step 5

    Set a second block next to the first. Tap the cinder block lightly with a rubber mallet to slide it closer to the first. The mortar joint between the two blocks should be 3/8 inch. Remove excess mortar that squeezes out from between the blocks with the tip of the trowel. Add more blocks until you have attached the entire first row.

  • Seth Seth on Mar 02, 2019


    Is this for a wall? is it above or below grade? Inside or outside? There are different grades of mortar mix depending on what you are using it for. Good choices for general applications are Type M or N mortar mix.

  • William William on Mar 02, 2019

    You can use concrete block construction adhesive in a caulk tube. You can also cement them with mortar mix.

  • Lynn Sorrell Lynn Sorrell on Mar 02, 2019

    with cement; here's video how to lay block another you can drill down into slab and add rebar for reinforcement then pour concrete inside cinder blocks around rebar; this is not necessary

  • Deb K Deb K on Nov 07, 2022

    Hi Brenda, hope this helps you out.