Dry Stacked Natural Stone Retaining Walls
Purchasing Your Boulders/Wall Stone:
When looking for natural stone for your future retaining wall,
first search for “gravel pits” in your area. Because they are in the
excavation business, they have access to the many boulders buried in their
pits, often setting them aside for sale to landscapers (or other consumers in
the know). Keep in mind, however, the machines they use are extremely large and
therefore unfit for loading boulders into your truck or trailer. Because of
this, you will find it necessary to either load them by hand (which can be very
difficult because of their shear weight and awkwardness) or you will need to
rent a small loader. If you rent a
loader to load the boulders, you will have to unload them by hand at the
jobsite. This too can be difficult if you do not have a dump truck or trailer.
However, with patience and the proper tools, you can do it this way and save
yourself a lot of money.
Stone Yards are another option. These are very popular for
several reasons: First, they can save you a lot of time and labor. Stone yards
can load the boulders for you if you have an open-bed vehicle. Also, stone
yards generally offer delivery. Second, stone yards have access to a wide
selection of stone from all over the country. The best yards can obtain stone
from all over the world. However, with selection comes increased price. Stone
yards sell stone significantly higher than gravel pits. They probably purchase
their boulders from gravel pits and must recover the cost of shipping the stone
from the pit to their own site. Not a cheap thing to do.
Depending on your location, you may be able to save even
more money by scamming fieldstone from fields in the area. Especially keep in
mind any farms or ranches you may have seen while driving around lately.
Farmers often have large piles of boulders moved aside while preparing their
fields for planting. Before you make off with any boulders, make sure you get
permission from the owner of the property from which you intend to "pilfer". Choosing the Right Stone For Your Dry Stacked Stone Wall Project:
Weight and Dimension:
It is essential, when choosing your rocks, to keep a few
things in mind. You may think my first recommendation is obvious, but it must
be said. It is easy to find boulders you love at the stone yard only to discover
when you get them to your site you can’t budge them. So, plan ahead. Know how
you intend to manipulate your boulders once they’re home. Don’t choose boulders
that you cannot move. That does not mean you must be able to pick them up.
However, you must determine your ability to access and use the
tools necessary for the project. (I will take you through some of the many
options available, and how to utilize those later).
Because stone density
varies due to composition, it is impossible to give you precise weights per
boulder or square face foot. Nevertheless, I have taken the time to give you
some estimates based on my experience and those of other professionals. Below
are estimates of weight based on dimension for various regions and rock type:
*Face feet assumes average thickness of the wall is 18". Actual thickness will affect Face Feet.*The List Below is stone readily available in Michigan:
Region Rock
Type Estimated Weight Pounds/Face Foot
Pennsylvania/NY Bluestone 162.5 pounds/cubic foot 243.75 lb/face footWisconson Chilton 168 pounds/cubic foot 252.00 lb/face foot
Wisconson Fon Du Loc 162 pounds/cubic foot 243.00 lb/face foot
Mid West Granite 160 pounds/ cubic foot 240.00 lb/face foot
Michigan Michigan Fieldstone 170 pounds/per cubic foot 255.00 lb/ face foot
Michigan Michigan Limestone 155 pounds per cubic foot 132.50 lb/ face foot
Canada Canadian Limestone 165 pounds per cubic foot 247.50 lb/face foot
Michigan Grindstone 136 pounds per cubic foot 204.00 lb/face foot
The Right-Size Wall Stone for Your Project
Building Stone: Different natural stone wall projects call for
different size stone. For the sake of stability, use the largest boulders
you can handle. Retaining walls under
two feet tall can be built using 10-18” boulders. Vary the sizes and shapes in
order to give it a more natural look. Larger walls should be built using 18”-36”
boulders. Boulders over 24” will probably require a machine to install.
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| Small Boulder Retaining Walls and Rosetta Dimensional Steps |
If the soil at your sight is rich in either clay or humus,
you will need crushed stone and rubble for backfill. Proper backfill improves
drainage and keeps frost heave (a problem in cold northern parts of the county)
from shoving boulders out of your wall.
Building Your Retaining Wall
Before you do anything else, locate any underground
utilities. Most municipalities have programs set up to provide free or
inexpensive utility location. Give them a call. In Michigan you need to call
MISS DIG. Next, mark out the base of your retaining wall using spray paint. Make
sure you keep in mind the set back. Allow for a minimum of 1 inch set back per
12 inches of height. For walls over five feet, set back should be 1.5” per ten
inches of height. Once you have marked
out the front of your wall, begin digging a trench approximately 1 ½ times the depth
and 2x the thickness of your average wall stone. Dig 6-12” in front of face of the wall. Boulder Walls can be built by simply digging
individual stones into the soil so they sit about 1/3 of the total height into the ground.
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| Chilton Dry-Stacked Retaining Wall |
If you are using stacked stone such as Chilton or Bluestone, it will be necessary to dig at least six inches deeper than the average thickness of your stones. This will allow for a compacted "chips n dust" or crushed concrete base. You will need to dig your trench wide enough to allow for a minimum of 6 inches in front, and 6 inches behind the wall's base layer. Thus, if your average wall stones are one (1) foot wide, front to back, you will dig your trench 2' wide. Doing this will ensure a stable base and keep your stones from sinking or tipping forward or backward.
To learn more about my services and begin planning your professionally designed and installed retaining wall project,
Call or Text Brent NOW
(616) 328-3258.
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