Tagged: Learn how to build stairs in retaining wall

Apr 01

How to Build Stairs in a Retaining Wall

How To Build Stairs In A Retaining Wall (courtesy of AllanBlock.com)

Whether built directly into the wall, in front of the wall, or sweeping off to the side, stairs are a great addition to almost any project!

When building stairs, choose your path wisely, and find the most natural path to maintain a comfortable rhythm to your stairway. You can break up long sets of steps with landings. Add a turn in in the landing, and break up a stair line. Or, use switch-backs or serpentines to meander up the hill. Tackle your slope by matching your stairway design to the natural grade of your slope.

On steep slopes, keep the blocks tight together. With AllenBlock, you get an 8-inch rise and a 12-inch run.

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

Landings are another way to soften a long stairway, and are an easy way to tie sets of steps together.

Stairs can be designed with flowing curves or straight lines.

Curved sidewalls create a softer look.

Straight sidewalls and corners create a crisp look, but will require more time to build.

Before you begin, you must determine how many steps you will need. Measure the total rise of your slope in inches, and divide by 8, which is the height of the blocks. Be sure to factor in any code requirements before you prep the site.

In this example, we will show you how to build stairs into a wall, using flowing curves. Remember, always begin building at the stair location, and build out.

Excavate the stairs. Once the number of steps has been determined, excavate the stair location, based on the rise and run in your approved plans.

The minimum width for a base trench is 24 inches.

The depth of the trench is determined by allowing for 6 inches of face material, plus 1 inch per foot of wall height. If organic or wet soils are still present in the base trench area, they must be removed and replaced with granular material.

Excavate the base trench to the necessary depth. Then, compact and level the base trench, making a minimum of 2 passes with a mechanical plate compactor.

Place the drain pipe at the lowest possible point, toward the back of the trench that can be vented to daylight every 50 feet.

Now that the base trench is ready, place a minimum of 6 inches of wall rock in the base trench and rake smooth. Compact the base, making a minimum of 2 passes.

Install the base course. Place the blocks toward the front of the trench, allowing for a minimum of 6 inches behind the blocks.

Then, fill in the area in front of the blocks with on site soils. This will keep the base course blocks from shifting, while filling and compacting.

Fill the hollow course – 12 inches behind the block, and the stair location – with wall rock.

Back fill and compact. Compact behind the block, in a path parallel to the wall, working from the back of the block to the back of the back fill area. Make a minimum of 2 passes with a mechanical plate compactor. Always compact in 8-inch lengths or less.

Remember to keep all heavy equipment at least 3 feet away from the back of the blocks.

Remove any excess soil from the top surface of the blocks by sweeping the blocks clean with a broom.

Use a level to scrape a stair tread area. Then, check the level from front to back and side to side, making sure the stair tread is level with the top of the first course of blocks.

Install the stair riser. Measure the distance for the next stair riser, and place the blocks, making sure to allow for 6 inches behind the block.

Measure the distance between the stairs to make sure that the blocks are parallel with the stairs in front.

Place a temporary block on top of the wall, close enough so that you can place a 4-foot level from the block to the stair riser block. This will ensure the stair riser block will be level with the rest of the wall. Then, level and adjust the rest of the stair riser block.

To continue building your wall out from the stair location, break the wings off the blocks by striking the wing with a hammer, to obtain a clean break. Then, place the blocks tight together, following the layout on the approved plans, making adjustments as necessary.

You can place a small amount of wall rock under the blocks to level them, then check again for level and make adjustments if necessary.

Place a small amount of wall rock in front of the blocks for the stair riser, to keep them from shifting during compaction.

Fill the hollow cores, 12 inches behind the block, and the next stair location with wall rock. Then, back fill any remaining area behind the wall rock with on site soils.

Run the plate compactor over the top of the blocks where there are 2 or more courses, and behind the block where there is only 1 course.

Continue compacting the wall rock behind the wall, as well as the excavated area of the next stair riser.

Screen the next stair tread area, and check for level from front to back and side to side.

Continue building. Measure the tread area to make sure it is parallel, and at the correct distance. Place the next temporary block to level the stair riser, and check for level.

Continue building the wall out from the stair location. Place some fill in front of the blocks. Fill the hollow cores and behind the blocks with wall rock. Fill in any remaining areas with on site soil. Then, run the plate compactor over the top of the blocks where there are 2 or more courses, and behind the blocks when there is only 1 course.

Continue compacting the wall rock behind the wall, as well as the excavated area of the next stair riser. Continue this process to the top of your wall.

Place the blocks for your next stair riser and measure for parallel and distance. Place a temporary block and adjust for level.

Build the wall out from the stair location.

Add fill in front of the blocks.

Fill the cores, behind the wall and the stair tread with wall rock.

Back fill any remaining areas and compact.

On the last course of the wall, you can choose to fill the block cores and the entire back fill area with plantable soils, to finish off your wall.

In this example, we’ve shown you how to build stairs into a wall. You can also build stairs in front of a wall, using curves, right angles or sweep them along the wall.

Or, let your imagination run wild, and create your own stair design! You can finish your stair treads with 1 of these options: AB capstones, AB capstones and pavers, pavers, or concrete. Choose the style that best compliments your landscape!

To enhance your project, view the other building options, or visit us at AllanBlock.com

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