I’m (OK, mostly my wife) installing a series of 2 steps, separated by an 8 foot stroll, then 2 steps, etc. that runs parallel to the front of the house. It will lead up to a forthcoming addition. The stair risers are granite “slabs” measuring about 8″h x13″d x7’w. The intervening space is infilled with 1/2″ gravel and topped with 2 or 3″ of sand, and covered with 1-1/4″ thick granite stones, 12″ square, each outlined with brick pavers. We are leaving a 20″ wide area of soil from the foundation to catch the drip off the roof (we have a french drain) and have planted it in low, moisture-loving mosses and other pretties.

Well, near the top level, the stairs come too close to the top of the foundation. I want to substitute a concrete gutter – draining into the existing system for the last 2 levels (one is 8 feet long, and the top step – actually the stoop – is 3 feet long) – for the soil. Since most of this is already in place, I don’t have the luxury of pouring a retaining wall. However, I only need to hold back about 8″ of the gravel.

Here is my tentative solution: (see the attached drawing – not to scale)
Dig a post hole below the center of each block, 18″ deep. Use standard concrete block set back beyond the 20″ line, anchored by rebar set diagonally through each block hole into the post hole, then filling it all with concrete. This will give me a solid wall along the line. I intend to construct the gutter out of concrete, using 1/4″ gravel, sand, fiber filler and 1/2″ “hardware cloth” mesh as reinforcement, with angle iron embedded into the top to support a grating. (The grating will be used to cover the gutter and support potted plants during the summer months.)

The only fill behind the block will be the tamped gravel, and the sand will be on top of the gravel, separated by geo fabric, and held back from the gutter by the gutter itself.

I realize this is a long post, and I apologize for that. I have been unable to find anyone who could advise me locally. Will my wall be sufficient. Is there a better mix I can use for the gutter? BTW, I am in South Carolina – pretty mild winters.

Thanks for your perseverance, and for the advice of those who informed me of using attachments.

Joe