are several ways to make fake rock or faux rock
and boulders all yielding good results.The price
and availability of the filler material you have
on site usually determines which is the best method
to make fake rock and boulders. Very true to life
representations of rocks and boulders can be achieved
by using some of the following materials.
Materials and Methods
Second hand bricks from demolished buildings or
Recycled real rocks
methods to make fake rock involve using some way
of giving an approximate shape to the finished rock
before the application of the mortar.
Forming the shape with chicken wire is a common
technique for smaller type rocks.
The general shape can be formed with carboard boxes
cut to size.
Reinforced metal bar material or expanded metal.
repetition of the same design the use of moulds
Casting from a mold
fastest and most inexpensive way to produce the
finished item will determine which method and material
you choose to make fake rock. The time the job takes
is based on how much detail is required. The more
definition and finish you give to each rock the
more time is involved.
boulders and other larger rocks usually look best
with a smoother and less detailed finish compared
to smaller decorative rocks and require less work
ensure the finished result of a faux rock landscaping
job looks natural, it is often required to use more
than one method. The final result will be much better
if you know how to use most of the methods to make
is the most widely used method and also the slowest
and most expensive. This method produces the closest
representation and feel to natural rock as it is
not of hollow construction like other methods to
make fake rock.
which are required for this method include:
is usually free or is already on site ready to be
disposed of. To ensure the rubble bonds together
it is advisable to hose it down to remove dust and
bricks and blocks of concrete
if purchased these materials are usually cheaper
than using concrete. Due to the regularity in shape
of the material it often makes it easier to construct
complicated shapes and designs such as waterfalls.
is a waste material used for packing and readily
available free from your local stores. It can be
cut to shape very easily and lowers the weight of
the finished faux rock. It holds the shape of the
rock and does not slump with the weight of the mortar,
unlike some of the other filler materials.
rock and other natural materials
shapes can be easily achieved with this material
which is often found on site. It is important to
wash the stone before use.
To aid in assembly of the faux rock, the material
can be placed in plastic bags if the pieces are
Cut open and expose the filler material
An acrylic polymer stabilizer mix can then be applied
to the rock in two coats. This will prepare the
structure for the final mortar mix by stabilizing
Apply the mortar mix in two 40mm coats.
Complete the process as described with the other
type of faux rock is relatively easy to make. It
also uses plain concrete and a basic mortar mix
for the final shaping to further save any complications.
You first need to build up a base for the rock in
concrete, then build up the shape a bit with some
rubble, add more concrete, more rubble again and
so on until you have achieved the finished shape.
make fake rock with this method it is a good idea
to be doing several rocks at the same time. As the
concrete sets on one piece of rock you can be creating
another piece. Once the rough shape is finished
and set up, the application of mortar can commence.
the mortar on rather than trowelling it as it tends
to adhere better. Additional layers of mortar also
adhere better to the rough texture left by the throwing
action. The finishing coats should start from the
top and work downwards. If you are working on two
rock shapes side by side be careful to emphasise
the join lines between the rocks. The definition
of these seems are very important to ensure a natural
Rock Construction Methods
method is suitable for making hollow rocks of a
Trim and form the chicken wire into roughly the
finished shape required.
Bend all sharp edges of wire inwards using pliers.
Soak old newspaper in a 50/50 dilution of woodworking
glue and wrap around the chicken wire form.
Now cover the wire form with several layers of Plaster
bandage that has been quickly dipped in water and
then allow to dry.
Decorate with diluted acrylic paint mixed 50/50
with sand to give a rock like texture.
and Expanded Metal Construction
method is popular to make fake rock which is hollow.
This method can create rocks and boulders which
can effectively camouflage garden utilities such
as garden taps and pool pumps. This method can produce
waterfalls to garden arches due to its ability to
be easily shaped.
you have set up the shape with the rebar, apply
the expanded metal to the structure. Secure it to
the rebar at intervals of 100 to 150mm. Make sure
it is not loose. Coat the structure with two 3 to
4cm coats of mortar mix leaving a minimum of an
hour or overnight between coats, depending on the
temperature of the day. Using similar techniques
to the solid fill method, add some texture to the
a mix of large and small cardboard boxes cut to
shape it is possible to build up a firm structure
very close to the desired rock shape. Using old
boxes from your local store, it is easy to create
faux rocks of all shapes and sizes and at low cost.
To create a firm structure in the form of the final
rock shape you can screw, staple, glue or wire the
cut cardboard boxes together.
Apply two coats of acrylic polymer stabilizer to
the cardboard structure in a throwing action with
the brush. If too much is applied at once there
is a danger that the cardboard will be soaked and
collapse. Allow the cardboard to dry between coats
to give it the required strength to support the
finishing mortar mix coat.
The mortar mix can now be applied in two coats of
The structure can now be textured, stained and sealed.
from a Mould.
a mould can produce the most accurate representation
from natural stone of all the methods. They are
perfect reproductions of stones in nature. The exact
same stone design can be manufactured over and over
again. Moulds can be made using latex or silicone
usually with a plaster back up mould to retain the
process of mould making for use with faux rocks
will be the subject of another article and will
deal with the use of texture moulds.
© 2010 Stan Alderson
here for more information on Faux Rocks