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Concrete Benchtops
Precast or in-situ
concrete benchtops can have a range of effects: raw or highly
finished; natural greys, tinted or integrally coloured; surface
patterned, stamped, acid–etched or crazed; sand/glass
blasted; or with exposed polished aggregates. There is no
limit to what you can create with this versatile material.
| Why build in concrete?
Concrete benchtops
are a highly desirable commodity, because concrete can
give warmth and a colour depth not available in granite
or marble. Due to concrete’s versatility, it is
one of the most extensively used building materials
in the world, mainly because it can easily be formed
into intricate shapes and is extremely durable.
Many homeowners are
taking advantage of concrete’s flexibility and
its capacity to integrate additional practical features
such as sinks, draining boards, backsplashes and wet
walls.
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Image compliments of Ross
Bannan |
Concrete benchtop surfaces develop their
own distinctive nature, depending on what the designer has
specified and how the eventual user treats it. As the owner
interacts with the benchtop the surface acquires its own character
over time. Its unpredictability is part of its attraction.
Texture and colour can vary, and regular use imparts a warm
patina or shine to the surface.
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Image compliments of Construction
Systems Ltd |
The
Contractor
Concrete benchtop
contractors will offer their own standard or individualised
colours. Samples can vary; due to each contractor’s
own method for building the benchtops, and utilizing
diverse types and amounts of cement and aggregates.
There are also a wide range pigments, stains, and
aggregate colours, so each concrete benchtop can be
as individual as you like. |
Check the Weight
The general rule of thumb for benchtops is
about 50mm thick. A 50mm thick slab weighs approximately 120Kg/m².
Floors and standard cabinetry should be checked for structural
soundness before the benchtop is designed, but most cabinetry
and floors should support the concrete slabs, as the weight
of the benchtop is distributed over a large area.
How it is done?
Benchtops are either precast in a shop or
built on site. Precast benchtops are poured in shops where
conditions are easily controlled. They use special casting
tables, which enable them to easily cure and seal the benchtop
before relocating it to your home, most owners prefer this
option as the kitchen or bathroom can be out of commission
for some time. Precast benchtops will give a finished surface
straight from the mould, only requiring a light sanding, polishing
and coating with sealers.
Benchtops built on site can easily be formed
to client’s specifications - radius edges, curved corners,
etc. In-situ or concrete cast in place needs to be hand-trowelled,
then left to cure for a week or so, prior to cutting, polishing
and coating with sealers.
Whichever approach you prefer, you can always
find a contractor who will do it for you.
What is it made of?
Concrete benchtops are comprised of cement,
aggregates, and a combination of admixtures. Other additives
such as fibre reinforcement, silica fume pozzolan, and acrylic
can be used as well.
Reinforcement and what does
it do?
Concrete benchtops can sometimes develop
hairline cracks, but these tend to be non-structural and result
from the natural shrinkage of the concrete. Your contractor
should use reinforcement, which may help to prevent these
cracks, which do not affect the durability of the concrete
and should be considered part of the distinctive nature of
your benchtop. The reinforcing used can be steel, wire mesh,
fibreglass, and/or fibres. Depending on the benchtop, more
than one type of reinforcement might be used.
Will they stain?
Concrete benchtops should always be cured
and then sealed. Your contractor will advise you on the sort
of sealant, method of placement and number of coats that they
need to apply.
The sealant is essential as it is water and
stain resistant. If left in its natural state, concrete’s
porous nature means it will stain. Staining can also occur
if cuts or the heat of hot pans has damaged the sealant, though
such an event is likely to damage other benchtop materials,
as well. Your contractor can provide you with information
on the sealers used and how to protect it.
How do I clean it?
Clean it like you would any other benchtop
with a mild, non-abrasive, non-ammoniated cleaner, your contractor
will advise you on what to use.
Remember to always make sure that the contractor has references
that vouch that they do the type of quality work you are looking
for.
For more information:
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