Retaining Wall: Capping Installation

A retaining wall
  • 10-20 hours
  • Intermediate
  • 400-3,000
What You'll Need
Bleach and mild laundry detergent
Scrub brush
Capping blocks or stones (solid concrete, pavers or other type)
Mortar mix
Mortar trowel
Concrete bond adhesive (optional but recommended)
Paint brush or roller
Wire brush

Installing wall capping on an existing retaining wall is a great way to give the old wall a new look or just make it look better in general. A wall cap can also help protect cinder block retaining walls by preventing too much moisture from entering the wall cavity. Installing cap blocks or stones on a retaining wall requires some labor, but it is not difficult to do. In fact, this simple how-to guide will show you everything you need to know to enhance the look of a retaining wall with cap blocks.

Step 1 - Choose Capping Blocks or Stones

First, you need to choose a type of capping block or stone for your retaining wall. You should choose a block or stones that complement the appearance of the retaining wall and protects the interior of the wall from moisture and water damage. For instance, if you have a retaining wall that is made of standard hollow concrete blocks, you may want to simply choose a solid cinder block made for topping these types of walls. If you have a brick retaining wall or poured concrete wall, you might want to select more decorative types of pavers or stones to cap your wall instead.

Step 2 - Clean Top Surface of Retaining Wall

If your retaining wall is more than a few weeks old, you should thoroughly scrub and clean the top surface of the wall. You can create a good cleaning solution by mixing some soap and water with a little chlorine bleach. Then, take a heavy-duty scrub brush and scrub the top of the retaining wall with the solution. Finally, rinse the top of the retaining wall and let it dry before continuing.

Step 3 - Apply Concrete Bond Adhesive

retaining wall

Although not absolutely necessary, using a good concrete bond adhesive on top of the retaining wall is an excellent idea. Concrete bond adhesive will allow the mortar you add later to secure the capping blocks or stones to better bond with the top surface of the retaining wall. You can apply a concrete bond adhesive with a paintbrush or roller. Using the adhesive will make working with the mortar and attaching the blocks or stones much easier.

Step 4 - Mix and Spread Mortar Mix

Follow the directions on the mortar mix bag and prepare the mortar mix for use.

Step 5 - Lay Capping Blocks

Begin placing the capping blocks or stones on top of the retaining wall. Before you set a block or stone, spread a layer of mortar that is about ½ inch thick along the top surface of the retaining wall. Don't get too far ahead of yourself; spread mortar in short runs. Position the caps or blocks so that they are evenly aligned with the wall or slightly offset to create a more pleasing appearance. If you do offset the blocks, make sure that the offset is aligned as well. Wipe off excess mortar mix as you go.

Step 6 - Clean Around Capping Blocks

Once the mortar dries, there will usually be some mortar that falls on the side of the wall or on the face of the capping block or stone. Take a wire brush and scrub away any dried mortar mix.