Hardscaping a Retaining Wall on a Hilly Site
At Art of Stone Gardening, we take pride in doing landscaping—and hardscaping—the right way. In this story, we show how we improved a home on a hill by building a parking space that will last for many years to come.
One of the challenges of living in the mountains is parking. Hilly home sites do not lend themselves to nice, flat parking spots. To make a parking area, many homeowners will pile soil behind a wood retaining wall. The problem is that wood rots and, unless the wall is installed properly, it always falls apart.
When we arrived at the site, the wood retaining wall was falling apart.
The smart choice in this situation was to build a retaining wall made of concrete blocks. We use blocks from manufacturer Allan Block.
Walls that need to support the weight of a car require the use of compacted soil, gravel, block, and if the wall is over four feet, Geogrid, a flexible mesh that restrains soil movement.
After we removed the wood wall, we excavated to find the native soil. Homebuilders will often level hilly sites with fill dirt that they dig up from the foundation. The problem with this is that fill dirt is much looser than the native soil and is not a proper base for a retaining wall. So we always build on native soil.
Once we hit native soil, we lay down gravel behind the wall. We compact it with a very heavy plate compactor. Gravel drains and compacts well. We add another layer of block, level it, then fill each block with gravel. More gravel is placed down behind the wall then compacted again. A drain pipe installed behind the wall directs water away. We keep adding rows, or “courses” of blocks, until we reach the desired height of the wall.
This wall sits in native soil. A drain pipe runs behind the wall to steer the water away.
One method of reinforcing an Allan Block retaining wall is to use Geogrid, which stabilizes the soil and gravel. We lay down the Geogrid mesh about every two courses.
Geogrid mesh stabilizes the soil and gravel. The finished wall is handsome and durable.
The wall blends into its surroundings.
Plenty of room for cars!
Sautee Nacoochee, GA