Rock garden steps with a retaining wall–part one

How to build stone garden steps with a small retaining wall for erosion control–part one

step by step instructions with photographs.

Ann is a gifted gardener and she is proud of her beautiful pool. Ann knows a lot about building and landscaping, but she decided to call in some help on this project. The problem was a set of “wobbly” steps going downhill, past a flower bed, to the ramp from the deck and the pool entrance. There was also an erosion problem above her perennial bed at the bottom of the hill. I decided that it would be a good time to provide step by step instructions for building rock steps and a simple retaining wall. Here’s the “before” picture:

scope: build wider, stable rock steps, take care of lower erosion

You can see that the stones were laid into the ground with no real provision for stability. They were too narrow, also, and by not being level, they became slippery in wet weather.

In the following picture, you can see part of the erosion problem at the bottom of the steps. This needed to be fixed, also, and the entire project needed to be tied in as a single entity.

an erosion problem at the bottom of the steps

The grass at the back side of the pool fence was probably a good idea at the time, but a lot of water runs down over it and the side of the hill is eroding. Ann loves her perennial flowers and wants to protect the lower bed. We decided to fix it with a French drain backed up with concrete “wall blocks.” I’ll show you more about wall blocks later in the article.

erosion problem below pool. How to solve the problem?

We began by removing all of the existing steps. We stretched a line from the top of the hill to the deck ramp. A line level was used to get an indication of the entire fall of the step project.

Using nylon string and a line level to determine number of rock steps

We measured from the level line to the ground to ascertain the number of 8 inch steps that would be required to line up perfectly with the landing at the bottom of the ramp. I used a calculator to multiply the number of feet by 12 to get the number of inches and then do divide by 8 (inches down per step) to get the number of steps. It came out to 5.25. I would need to divide up that quarter of a step somewhere in the layout.

Measuring down from level line to determine number of steps

We would be using 12 inch concrete blocks to form the foundation for the steps. These blocks measure 16 inches long by 8 inches high by 12 inches deep. They are perfect for steps because the finished dimensions of a comfortable step should be 12 inches out by 8 inches down. These steps will be 32 inches wide for further comfort. We laid the first two steps perfectly level in all directions with the top of the block far enough down from the grass to allow for rock veneer on the top. A slow and careful beginning is essential because verything has to work out just right.

The first step must be laid in to perfection

We continued laying the blocks, moving out and down so that the number of actual steps would end up at the proper level at the bottom. The quarter step difference is worked out in fractions as we go down. The catch basin which was originally put in for drainage will be removed and replaced with cement. The steps will take care of the water, acting as a “waterfall” in rainy weather. The project is starting to take shape:

concrete block framework for stone steps

When the step foundation reached the bottom of the steps, it was time to form in a landing. In order to make everything work out properly, the retaining wall had to be started at this point.

stop here to determine level of retaining wall

We used a string and a line level to determine the bottom level for the wall and dug out for the basic wall foundation. The wall will consist of wall blocks backed up by a 4 inch perforated drain pipe with gravel over it. This is digging as an art form.

foundation dug for base of block retaining wall

The initial wall block is set in place leaving room for the drain pipe and gravel. The level on top of the block indicates that we have the right amount of room for the 4 inch cap stone to bring the level up to exactly where we want it.

initial block in place for retaining wall. Note room for four inch cap.

The steps and the wall come together. It is now time to begin framing in the landing.

foundations for rock steps and retaining wall come together

We use wood forming to tie the base of the ramp into the back side of the landing. This will be filled in with concrete.

Wooden forms installed to pour concrete from the ramp to the rock step landing

We finish laying the blocks which will provide the final step to the walkway which will lead to the pool entrance. Note that wherever the blocks don’t fit tight, the spaces are filled in with mortar mix.

Now it is time to apply the rock to the step “risers.” We have found that we get much better results if we apply the riser facing to begin with. By doing this, the rocks on the tops of the steps will lock the risers in, providing a more durable finished project. It is also much easier in the long run. First, we measure and cut each rock. We use an angle grinder with a diamond blade to score the rocks on each side and then pop it with a hammer.

Sticking rock veneer on an upright surface requires a bit of technique. What we do is to build an actual “suction cup” with the mortar mix. When the rock is applied to the riser, the mortar gives as the air is forced out. This works just like a suction cup on a kid’s play arrows.