Prior to starting the process of building your steps, you have to decide the shape you’re wanting, as well as the elevation of each step. Typically, you would want to try staying within a 6-7” rise for a comfortable step. Once you have that figured out, you can move onto preparing your base.
Step 1: Excavation & Base Preparation
To prepare your base, you’ll want to dig a trench. The trench will be slightly wider than the block you chose and about 8” to 1 deeper than the bottom of the block. Keep in mind that at least 1 row of the SRW block (segmental retaining wall) should be buried to prevent it from shifting forward and give it more strength l.
After the subgrade of the trench is compacted, ¾” crush (base gravel) can be added, levelled, and compacted.
This step may be repeated more than once to ensure that the gravel base if both level and properly compacted. Remember that there is 1” to 1.5” of screening (stone dust) that goes over that.
Step 2: Leveling of the Bedding Sand
By having screening underneath, it will allow you to adjust and level your wall easier while embedding them into the screening which keeps it in place.
Here at Milton Stone Group, we most often use
(1” square tubing) to help level our screening. The bars are placed on the gravel base and then adjusted to the proper height. Once the parallel bars are placed and set, you can add the screening. Pull your level (or equivalent) across the bars.
To ensure that the screening has a consistent density, compact it lightly either with your a 10×10” tamper, screeding it the first time, then repeating to create a perfectly level surface.
Make sure to remove the screeding bars and trowel some more screening into the voids if they’re in the way of your wall.
Step 3: Install your RWS Blocks
Once the bedding sand is leveled, you can start setting your SRW blocks in place. Before laying your first block, make a mark in the sand to indicate the front of your blocks. If you’re not able to make it perfectly straight you can place pickets with a string line. Doing this will keep the blocks as consistent as possible while you’re laying them.
Keep in mind that different blocks have different locking mechanisms that may protrude under the block.
It’s important to note that, when placing the blocks, do not slide them on your base sand. Instead, set them directly down, gently rubbing against the previous block each time.
Once the entire course of blocks have been set down, some adjustments may need to be made. Now would be the time to do it. Using a level and a rubber mallet, ensure that the blocks are laying consistently side-to-side, and level from front to back with no high or low spots in between. Remember that one row is always buried (you will not see it). Make sure to stagger/interlock them.
Step 4: Install your Coping
Once the bottom course of blocks is leveled and in line with each other, you can start placing the caps on the blocks. Depending on the shape and length of your step, some caps may have to be cut using a diamond-blade concrete saw.
It’s always important to try and maintain a stagger with the blocks below.
Step 5: Glue your Coping
When all the coping caps have been dry fit, remove one at the time and place generous amounts of PL concrete adhesive on top. Be sure to stay at least a couple of inches away from the front of the block to prevent the glue from squeezing out and being visible.
Place your caps back on top in the same order as you removed them. Ensure that the caps are in line with each other and stay off of them for a minimum of an hour, depending on weather conditions.
Step 6: Install The Next Step
At this point, you can start preparing the base gravel behind to get ready for the next set of steps. It’s important that any voids between the back of the blocks of the step below be filled, especially when your steps are curved.
Once done, you can start backfilling with your base gravel. Use a tamper to compact the gravel in thin layers to ensure a maximum compaction. The height of gravel will be determined by the height of each step and the dimensions of the blocks you’re using.
Be sure to leave enough room for another 1-1.5” layer of bedding sand. Remember to always bury a row for more strength and durability.
Step 7: Repeat if Needed
Start back at the beginning for the next step and repeat for each following step.