Elimination of vegetal growth

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.

 

      Surface cleaning

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 unabated.

   

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.

 

      Plastic repair

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.

 

      Pointing

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 texture.

 

      Finishes

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.

 

      Structural consolidation

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.

 

      Stone replacement

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.

 

Source: Perit Edward Said