While the short answer is yes, a fence can be built above a
retaining wall; the real question is if the fence is being built above an
existing retaining wall or are the wall and fence being constructed at the same
time?
If the retaining wall is already built it may be too late to
add a fence, or at the very least you may have to give up valuable space behind
the wall in order to build it. It is important to know how the retaining wall
was built before you proceed with fence construction so the fence installer
doesn’t damage the structural integrity of the wall.
If geogrid
(mesh reinforcement) was used in the construction of the wall the fence install
could tear the grid during construction of the fence which could cause the wall
to fail, and if the wall was constructed using No-Fines
Concrete the fence installer will not be able to install a fence behind the
wall once it has been built. So don’t
wait until the wall is built before you think about the fence!
Here are a few ways to
tackle adding a fence above a retaining wall during your retaining wall
planning phase:
Place the fence a minimum of 3 ft. (0.9 m) behind the back
of the retaining wall. This method is
the preferred because it does not require extra engineering.Construction tubes are placed
for the fence posts during the construction of the wall.
A second method is to have the fence directly behind the
wall; this method requires a fence above the wall overturning calculation to be
completed to understand how the fence interacts with the wall. This calculation
is to determine the fence parameters; how deep do the posts need to be placed,
how far apart are the posts, how tall is the fence? These factors impact the
wall which may cause the top to overturn and fail. To have the fence directly
behind the wall you will have to install the construction tubes during the
construction of the wall, just like the first method.
Another way to have the fence directly behind the wall is to
use a product called Sleeve-
It. Sleeve- It is a product that is installed during the wall construction
but it does not require extra engineering for overturning.
For more information, check out our tech sheet on Fences
above Retaining Walls or visit our website at allanblock.com
Thanks. This blog helps
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