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Chemical Injection

Pressure injection chemical dampproof courses have been successfully used for over 25 years and is a nominated method on restoration projects throughout the world.

The Westox Injection System has consistently been used by Restoration Bodies on many of Australia’s oldest buildings, ranging from Victorian Terraces to major conservation projects. The advantage of this injection system includes the level of installation which may be lower than some other commonly used methods. This provides protection to the skirting boards and can avoid dampness bridging through the new plaster. Speed and cleanliness of installation are two other factors in arriving at an objective choice.
 
Approved Applicators of the Westox Chemical Dampproof Courses carry out a careful survey of the problem and provide a written report and quotation.
 
As an accurate diagnosis is critical in making an appraisal of any dampness problem, an electronic meter is used to assess moisture content and to identify it’s source. It is not uncommon to see properties treated at great expense for rising damp when the problem could be as simple as a broken down pipe or other minor repair.
 
After installation of the new damp course, the walls will gradually dry out. Depending on the moisture content and the thickness of the walls, this could take in excess of one year. The replacement of all damp affected plaster is essential to prevent secondary dampness.
 
Salt contamination of the old plaster is caused by the moisture containing salts, rising up through the capillaries of the brickwork from the ground below. These salts build up in the plaster over a period of time and attract airborne moisture. It is the expansion and contraction of these salts which cause the familiar rising damp symptoms of eroding and blistering paints and plaster. The major proportion of the salts are removed with the older plaster. The new render is designed to allow the passage of water vapour, so that the residual moisture can dissipate from the wall. With the use of a special formulated cement additive called Westox Salt Retarder, the old plaster can be replaced soon after the installation of the new dampproof course.
 
On the commencement of a typical rising damp project the applicator removes the original skirtings. Skirtings may be refitted after the installation of the chemical dampproof course and the completion of the replastering. In some cases the skirtings may be rotten and require replacement. The damp effected plaster is then removed to expose the brick or stone.
 
After selecting the course of brick or stone which will become the new dampproof course, a series of 10mm holes are drilled at an appropriate depth and spacing. The injecting lances are then introduced into the holes and a seal is formed by a rubber expansion washer which holds the lance firmly into the brick or stone. 
 
The selected Westox Injection Fluid is them pumped via flexible tubing into the brickwork and the fluid, now under pressure is forced through the capillaries of the brick or stone until it is  visually evident that saturation has taken place.
 
The lances are then removed and the procedure repeated progressing along the wall to be treated. The injection fluid continues to penetrate through masonry and mortar joints by capillarity for approximately 24 hours.
 
After the full thickness of the wall is injected the continuous saturated section of masonry will become the new dampproof course. After a short drying period the walls may be replastered to complete the job.
 
The Westox Chemical Dampproof Course is covered by the written 20 year guarantee which covers both materials and workmanship but only applies if the work is undertaken by a Westox Approved Contractor.