POURING AND FINISHING AN EXPOSED AGGREGATE WALKWAY
Shawn Joslin adds a joint line
to his walkway project.
Keep trowel marks to a minimum when preparing to wash
consistent the gravel pattern will
be, and to some degree how flat
the finished job will be.
As you “rod” the concrete, or
in other words, level it with a
screed rod (I just use a 2-by- 4)
as it is being poured, the gravel
near the top is being pushed
down. This pushing down of the
gravel continues during the bull-float process and the mag-float
part of the finishing job. As the
gravel goes down, the “fines” or
“cream” rises, which means you
are creating a layer of concrete
at the top with sand only as the
aggregate. This is a good thing
for smooth- and broom-finish
jobs, but not so good for
exposed because you have to
cut deeper to get to the gravel.
As you can imagine, inconsistency in rodding, bull-floating
and magging can cause unseen
differences in the gravel level
within the pour. Unseen, that
is, until you start washing the
Therefore, consistency is one
of the keys to a good finish job
in exposed aggregate. Rod it the
same way throughout the pour.
Bull-float the entire job in the
same direction, with the same
number of passes and with
about the same pressure. If you
have a low spot, sprinkle in
more whole concrete mix, don’t
just rake in some fine material
from the top. Try to be consistent throughout with the mag-float, edgers and jointers.
Once the entire job is smooth,
The bullnose shape of an edge
trowel helps release the forms,
which are removed earlier than
usual for washing.
A spray can is the recommended tool for applying surface
RULES AND REGS
Check on permit and code requirements before beginning your walkway project. If your project is a sidewalk along a
public street, there are probably very detailed requirements in width, slope and finishes. Most municipalities specify
the angle at which a sidewalk meets a driveway to avoid steep climbs for neighbors with disabilities. Plans must be
approved, and often an inspection is required before you pour the concrete.
Community covenants may also be specific about the type of concrete finishes you can use in the areas in front of
the house. Often these rules require the use of exposed aggregate for walkways or for driveway borders and bands.