Dooler wrote:

I have fence company installing a retaining wall 2' tall and a fence.
They have done retaining walls before and seem to know what they are
doing, but they are setting the prefab stones at ground level (they
flattened and leveled even with sidewalk) with crushed rock on top
rather than dig down 3" + gravel as per the instructions of
mutualmaterial.com states for manorstones. When questioned, owner
said they will put dirt in front (wall inset from sidewalk a foot).

They just finished first day and got ground level and just started
putting blocks in. Quick recommendation/help appreciated.

This is NOT a retaining wall.

A true retaining wall -- engineered to hold back a slope -- has a
below-ground concrete footing wider than the wall. The depth of
the footing is proportional to the height of the wall. The wall
itself needs steel rods that extend into the footing (placed before
the footing concrete is poured), surrounded within the wall's
vertical channels with more concrete. Where appreciable force from
the slope is expected, horizontal steel rods within the footings
and the wall itself might also be required. This use of steel and
concrete is dictated by the force of the slope behind the wall, and
not by the wall's height; that is, even a low retaining wall
requires this.

Perhaps you are getting a slough wall, which does not support a
slope. A slough wall merely prevents loose dirt and other material
-- slough (pronounced "sluff") -- from trickling or eroding down
the slope. I have a slough wall at the base of the hill in my back
yard. The toe of the slope is at the bottom of the wall, not near
the top. The slope was engineered (benched and compacted) so that
no retaining wall would be needed.

You can read about my hill and slough wall at
http://www.rossde.com/garden/garden_back.html#hill.

--

David E. Ross
http://www.rossde.com/

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