All vegetal growth is eradicated using herbicides followed by the manual removal
of foliage and where possible, rooting systems taking care not to disturb friable
stonework. Where necessary, masonry elements are dismantled in order to ensure total
elimination of roots.
Removal of obsolete inserts and attachments
During the repair of masonry surfaces, the presence of attachments such as metal
nails, wooden dowels, defunct pipe work, etc is undesirable. These are meticulously
removed one by one by impinging the least possible impact on the limestone fabric.
All holes left in the process are then made good accordingly.
Removal of renders
All cementitious surface renders are usually removed during the restoration of masonry
structures. Depending on the stubbornness of the render, different methods can be
introduced in order to eliminate them. These range from handheld tools such as small
picks and French hammers to mechanical devices such as manual pneumatic hammers.
Lime-based renders and paint coatings will normally be less difficult to remove and
can be done by manual tools or methods such as JOS system.
This process can range from simple superficial hand-brushing of the masonry in order
to remove superficial dirt, to the employment of mechanical methods for more stubborn
soiling. Either way, the faces are cleaned ensuring that the characteristic patina
is retained, particularly if surfaces are external. Mechanical systems such as the
JOS Cleaning System is set to use minimum amounts of water and calcium carbonate
as a means of removal. This method can be used to break away layers of paint.
Jos Cleaning System
The JOS cleaning system gives a new dimension to the cleaning technology doing no
harm to natural elements as it is set to use minimum amounts of water and calcium
carbonate. It allows the operator full control of the pressure, volume of water and
quantity of calcium carbonate used. This enables the masonry fabric to remain unharmed.
Unlike sand blasting machines the JOS system is a micro blasting machine which enables
to preserve the original patina of the stone. There is no other method of cleaning
which is as gentle as the swirl action of the JOS system. Cleaning is carried out
by a mixture of air, fine inert powder and very little water which is developed into
a swirling vortex by means of a specially constructed nozzle. The special feature
of this technique is that the vortex emerging from the nozzle expands rapidly and
that, as a result, the pressure of the compressed air diminishes approximately in
proportion to the square of the distance, whilst the rotation of the vortex continues
The advantage of this cleaning process is that this technique can be used almost
without limit on many different kinds of building material, and that the degree of
cleaning can be individually adjusted.
The JOS system is ideal and safe for the removal of carbon pollutants from: stone,
brick, terracotta, ceramic tiles, glass, concrete and many other materials. It is
also suitable for the cleaning of surfaces such as bronze, brass, copper and aluminium.
Of all methods of cleaning technology now available, JOS has proved to be very cost
effective when one considers its gentleness while working and that its way of cleaning,
unlike other methods of cleaning, does not deteriorate the natural patina of time
from the surface being cleaned. This factor cannot be achieved with any other physical
cleaning technique. The results are astonishing and they cannot be compared with
any other cleaning system.
Stone desalination and consolidation
Given the saline nature of the local environment, it is sometimes necessary to address
the problem of masonry that is continuously decaying typically by powdering or flaking.
In these situations, the limestone fabric is tested to confirm the presence and determine
the make-up of soluble salts after which it is desalinated to acceptable levels using
methods which employ techniques such as poulticing. Depending on the level of decay
and its surroundings, the fabric is then consolidated using specially designed and
tested products that mitigate deterioration. Interventions such as plastic repair
can be carried out after the desalination process.
Where stone replacement is not possible or feasible, plastic repair is another option
that can be considered particularly where damage is superficial or minor. This flexible
method involves the employment of a lime-based mortar which is built up in layers
in order to ensure maximum strength and reinforced where necessary using carbon-fibre
rods and plastic meshes. The newly regained surfaces are then finished using a fine
render attaining desired colours and texture.
A number of mortars mixes can be prepared for pointing of masonry structures. These
are designed in accordance with a number of factors such as rate of decay, dimensions
of mortar joints, the subjected climate and the appearance of the surrounding masonry
which will then determine the characteristics of the mix. A suitable mix will then
be prepared and tested in site for workability, performance, hardness, colour and
The possibility of finishing the repaired surfaces by applying a light lime-based
coating (M. velatura) can be considered. Such an intervention will homogenise the
repairs by equalising the replaced stone elements and the original fabric. This will
ensure an overall visual integrity of the restored structures.
A number of mechanical techniques are offered for different degrees of structural
instability in masonry buildings. These range from localised repairs including the
meticulous reintegration of elements such as cracked lintels (M. blajjet) and roofing
slabs (M. xorok) using specially designed grouts and attachments, to the more complex
consolidation of entire sections of buildings using a variety of structural solutions
such as metres-long stainless steel rods, ties and belts and proprietary grouts.
Where deemed necessary, deteriorated stonework ranging from ashlar blocks to intricately
carved elements can be carefully removed and substituted as per original dimensions
and profiles. All limestone, both globigerina (M. franka) and coralline (M. qawwi),
is procured from specially selected quarries ensuring the best possible quality.
Dismantling and reconstruction
In situations where masonry structures are unstable but elements are in a good state
of preservation then these can be salvaged and used in reconstruction. Such a process
includes the careful documentation of the elements using methods such as photography,
numeration and cataloguing. Arches, roofing systems, flagstone floorings and entire
walls have been dismantled and reassembled in this way.