How to Build Retaining Wall Stairs: A 14-Step Easy Guide

Retaining walls help prevent soil erosion in sloped yards but can make it hard to move around. And 1 great solution is that you can incorporate retaining wall stairs into the design. 

Learning how to build retaining wall stairs allows you to create seamless access while enhancing both the functionality and appearance of your yard. These stairs fit right into the wall, making your yard more functional and attractive.

Retaining wall stairs: 3 step tread options

When building retaining wall and stairs, using the same blocks as the retaining wall creates a unified and cohesive design. This ensures the stairs blend seamlessly with the rest of the wall. Blocks with a 6 to 8 inches height work well for creating comfortable risers for outdoor steps.

There are 3 common ways to build retaining wall stair treads:

1. Open treads: Use retaining wall blocks and gravel backfill to create the tread. This method is simple but has a more basic, functional look.
2. Capstones: Capstones with a finished front edge create the tread. They give the stairs a more polished look, especially for steep steps with short treads.
3. Pavers or bricks: Smaller pavers or bricks that complement the wall blocks can be used for the treads, adding more style to the steps.

When should you build retaining wall stairs?

To ensure a seamless integration and consistent look, it’s best to build the retaining wall stairs at the same time as the retaining wall itself. This allows the block courses to align perfectly between the wall and the stairs, creating a unified structure. 

When starting the project, always prioritize constructing the stairs first before proceeding with the rest of the wall. Additionally, make sure to build the stairs when the ground is dry to maintain stability and reduce the risk of shifting or settling after completion.

How many steps do I need?

If you want to build retaining wall stairs, it’s important to figure out how many steps you will need, you can follow these simple steps:

1. Place one end of a short piece of two-by-four at the top of the slope.
2. Use a bubble level to make sure the board is perfectly level.
3. Measure the distance from the bottom of the two-by-four down to the ground. This is your total stair rise.
4. Divide the total stair rise by the height of each step to determine how many steps you’ll need.

Total rise (Inches)	Number of steps needed (8-inch step)
16	2
24	3
32	4
40	5
48	6
56	7
64	8
72	9
80	10

Safety consideration

Most communities have regulations about the height of retaining walls, especially those with retaining wall stairs, to ensure safety and uniformity. If your wall is below a certain height, you might not need a permit, but these height limits are often quite low.

To ensure you’re in compliance, check with your local permitting office for guidelines on building both the retaining wall and retaining wall with stairs. In some cases, you may also need to install railings for added safety, depending on local rules.

Related:

10 brilliant retaining wall stair ideas to enhance your garden

4 types of retaining walls you must know

Building retaining wall stairs: 14 steps guidance

Adding retaining wall steps to your garden or backyard is an excellent alternative to sloping paths, and the best part is that you can install them yourself! This step-by-step guide will show you how to build retaining wall stairs easily.

Equipments and materials you’ll need

Tools & Equipment:

• Tape measure
• Bubble level
• 2×4 board
• Shovel
• Tamper or plate compactor
• Broom

Materials:

• 8-inch retaining wall blocks
• Gravel
• Tread covers (optional)
• Landscape block adhesive
• Drain pipe (if necessary)

Retaining wall stairs step-by-step instruction

Step 1: Determine the total stair rise:

• Place a 2×4 with a bubble level on top of it, ensuring one end rests at the top of the slope.
• Adjust the 2×4 until it’s level, then measure the distance from the bottom of the board to the ground. This is your total stair rise.

Step 2: Determine the number of stairs:

• Divide the total stair rise by the height of each block (e.g., 8 inches) to calculate the number of steps required.
• For steep slopes, aim for an 8-inch rise and a 12-inch tread per step. On gentler slopes, you can pair an 8-inch rise with a longer tread.

Step 3: Excavate the location:

• Use a shovel to dig out the stair steps, shaping them to match the retaining wall stairs’ intended form.
• Remove more soil than expected to allow for adequate base material underneath and behind the stairs.

Step 4: Prepare the base trench:

• Dig a trench for the retaining wall, which will also serve as the base for the first step.
• The trench should be at least 24 inches wide and 6 inches deep. For the first step, dig a trench at least 6 inches deep and fill it with landscape gravel.
• Adjust the gravel depth to match the height of the first block course.

Step 5: Install the drain pipe (Optional):

• If required by soil conditions or regulations, embed a drain pipe at the base trench to manage water drainage.

Step 6: Level and compact the base trench:

• Use a bubble level to check if the gravel in the base trench is even. Adjust as needed.
• Compact the gravel using a tamping tool or plate compactor.

Step 7: Install the first course:

• Place the first row of retaining wall blocks on the compacted gravel, ensuring the raised lip is facing up and at the front.
• Use a level to check the alignment of the blocks side-to-side and adjust with twine or mason’s string if necessary.

Step 8: Backfill the first course:

• Add soil in front of the first course to stabilize the blocks.
• Fill the area behind the first course with gravel, compact it, and fill any hollow block cores if applicable.

Step 9: Level and screed the first step:

• Sweep the first course clean and level it from front to back.
• Use a two-by-four to screed the gravel evenly.

Step 10: Install the second step:

• Place the second set of blocks behind the first, creating a six-inch base behind the first step.
• Measure the tread depth to keep the second step parallel to the first.

Step 11: Backfill the second course:

• Add gravel behind the second set of blocks, filling hollow cores if needed, and compact the backfill.

Step 12: Continue building the steps:

• Repeat the process, stacking and backfilling until you reach the top of the slope.

Step 13: Add the tread covers:

• Choose whether to leave the treads open or cover them with capstones, pavers, or bricks.
• Clean the treads and apply landscape block adhesive to the tops of the blocks, securing the chosen tread covers.

Step 14: Build out the retaining wall:

• After finishing the stairs, continue building the retaining wall along both sides, using the stair courses as a guide.

When to call a professional to help

Integrating retaining wall stairs into an existing wall can be challenging, especially when dealing with curved steps, landings, switchbacks, sidewalls, planters, or other unique features. These designs require precise construction techniques, making it tricky to achieve a seamless blend. For help with these advanced installations, it’s best to contact a professional landscaping or paving company.

Choose Mile High Lifescape for expert handling of curved stairs, landings, switchbacks, and other complex retaining wall features. Our skilled team ensures seamless integration with your existing wall, delivering exceptional craftsmanship and attention to detail. Contact us today for professional assistance with your project.

Address: 1427 S Federal Blvd, Denver, CO 80219

Hotline: +1 (720) 301-3335

Email: [email protected]

Reference

1. How to Build Retaining Wall Steps. Available at: https://www.thespruce.com/retaining-wall-stairs-5341402  

2. How to Install Steps With Retaining Wall Blocks. Available at: https://www.hilgersom-inc.com/blog/2018/5/17/how-to-build-steps-with-blocks