EXPERT ADVICE(^) // ARCHITECTURE
a thin top layer of the concrete cut away to
reveal the full eff ect of the aggregates.
For the most basic of concrete fl oors,
either internal or external, you may hear
architects and designers ask for a range of
trowelled fi nishes. These include:
COVE FINISH
A semi-rough textured fi nish that looks
like swirls and fi gure 8s when applied. A
common fi nish to driveways, pathways,
outdoor entertainment areas and swimming
pool walkways.
WOOD FLOAT
A similar look to the cove. Rarely used
except on heavily sloped driveways and
under tiles to provide added grip.
BROOM
A simple fi nish using a broom but gives a
clean and uniform look.
STEEL TROWEL
In small concrete spaces, a steel trowel is
used by hand to give a smooth surface. Great
for areas that need to be easily maintained
like garages and outdoor kitchens.
MACHINE TROWEL
A machine trowel gives a smoother fi nish
and is used to cover larger areas. It also
hardens and seals the surface, making it
almost resistant to chipping and breaks.
Great for house slabs and garages.
CLEAR RESIN SEALERS
These are used to protect the concrete
from stains.
Laying concrete is like making a fi nger
print — no two concrete slabs are the same.
Concrete in all its wondrous, varied forms
is still one of the best building materials to
use in almost all circumstances. Depending
on location and accessibility, it can be
comparable in cost to other lighter forms of
fi nishes and construction.
Even left in its natural state, concrete
has become one of the leading design
trends in recent years. You can always lay
other surfaces over concrete but you can’t
always lay concrete over another surface. Its
thermal qualities are excellent and can be
engineered to carry any load.
When you consider that fl oors, driveways,
terraces and courtyards make up an
enormous area of the home, consideration
must be given to how these surfaces tie
together. Using one versatile, durable,
timeless material such as concrete in all its
varied fi nishes and forms makes both design
and structural sense.
Remember, the Romans built an
empire with concrete, so think about the
possibilities at your place.
VALUABLE SOURCES
Cement, Concrete & Aggregates Australia,
Geostone Australia
TIPS
The only way to choose aggregates is
to sample them while planning your job.
Aggregates can come from anywhere
but it’s best to choose those available
in your area, which is often determined
by the quarries that supply to concrete
manufacturers.
All concrete is subject to cracking. This
can be minimised by putting in control
joints, the curing process, and pouring on
the right day. There’s a range of methods
and theories to minimise cracking, so
make sure your builder/concreter has
the experience and knowledge to get the
pour right.
Ensure your concreter uses only
commercially available retarders (a
chemical used to prevent the top layer
of the concrete from hardening). Sugar
is often used, but take care as it can lead
to an inconsistent fi nish — unless that is
what you want.
It is essential to use steel reinforcement
to provide both additional strength
and to assist in controlling the natural
movement of the concrete. For internal
polished fl oors, make sure you consult
with your structural engineer, architect
or designer.
Don’t make a small concrete area
(for example, a space the size of your
average bathroom) too busy with large
aggregates. Proportionally, the larger the
area, the larger the aggregates.
Concreteologist House from Grand
Designs New Zealand Series Two