Building Stairs

Stairs can be designed with flowing curves or straight lines. Curved sidewalls create a softer, natural look. Straight sidewalls and corners offer a crisp, traditional style; however they require AB Corner Blocks and take more time to build. Stairs can be built using the AB Junior or the AB Jumbo Junior.

How Many Steps?

how many steps

To find the number of steps needed in a garden wall, measure the total rise of your slope in inches and divide by the height of the block.
AB Jumbo Junior = 7.5 in. high (190 mm) AB Junior = 6 in. high (150 mm)

Stair Types

Stair Tread Types

Tackle Your Slope

Match your stairway design to the natural grade of your slope.

Stairs Steep Slopes

On steep slopes, keep the steps close together and use our AB Capstone for a 12 in. (305 mm) tread.

Stairs Gentle Slopes

On gentle slopes, add pavers or other materials to increase the depth of the tread and length of the run.

Stairs with Landings

Landings can soften a long stairway and provide an easy way to tie the sets of steps together.

Place First Step

Excavate slope and place first step on compacted base

Install AB Capstone and second riser

Install AB Capstone and second riser

Repeat to top of slope

Repeat to top of slope

Space steps apart on gentle slopes

Space steps apart on gentle slopes

Basic Stair Construction

Once you've picked a stair design, remove any sod or other surface materials and begin to rough in the grades. Be sure to install side garden walls first if they are part of your design, and make sure to bury enough of the base blocks so the side walls are fully covered by the finished steps.

Tight Stairs with AB Capstones

This arrangement will give you 7.5 in. (190 mm) risers and 11 in. (280 mm) treads using the AB Jumbo Juniors.

  • Excavate the area for the stairway. Make the bottom trench 12 in. (300 mm) wide. At the back of the trench, step up 6 in. (150 mm) and excavate back another 12 in. (300 mm). Step up again to the top of the slope.
  • Place 4 in. (100 mm) of wall rock in the trench and compact thoroughly. Set the AB Jumbo Juniors in place to form the first riser. Fill the block and behind with more wall rock and carefully compact again to lock in place. Check for level and adjust if needed.
  • Install the cap blocks on the first course. Place the second riser to fit snugly against the back of the cap block on the first riser. The bottom of the blocks should be set at the same height as the top of the lower set of blocks. This arrangement will give you a the same rise in each step.
  • Fill the blocks and behind to the back of the trench, and compact again to lock the second riser in place.

Wider Steps

  • To build wider steps, simply excavate the back of each trench to allow for additional tread depth. It is a good idea to make each tread uniform in width. If you are using pavers to complete the surface of the treads, try to set the depth so full size pavers will fill it in. This will eliminate cutting. Be sure to slope the treads slightly downward to allow for proper drainage.

Taller Steps

  • If you have steeper slopes, use the same construction shown above. Be sure to check your local building codes to make sure the taller steps meet code.
AB Capstone

AB Capstone

AB Garden Cap and Pavers

AB Garden Cap and Pavers

Stair Tread Options

Allan Block’s patented front lip provides a built-in edging that works well when installing the stair tread material. Allan Block Caps, pavers, crushed rock, mulches and flagstone are good stair tread examples. Ensure that stair treads are glued in place for safe use.