Aqueous DPC Concentrate

Technical Data Sheet

1. DESCRIPTION

Antel Silicone Waterbased D P C Concentrate is a formulated, partially diluted aqueous concentrate of potassium methyl siliconate.   Regular quality control checks for specific gravity, pH and silicone content are carried out on the concentrate.

2.   USES

The system involves dilution of the fluid, the saturation of a selected course or courses with the diluted fluid by pressure injection, and subsequent replastering.

3.   PACKAGING

5 litre plastic bottles.  6 x 5 litre bottles per case.

4.   USAGE RATE

4.5 litres of fluid are normally used for the treatment of rubble core in 1 metre of a 450 mm wall (increase pro- rata for walls of greater thickness).

5.   STORAGE 

Store in cool dry conditions in original containers.

Protect from freezing.  Keep out of reach of children. 

6.   HEALTH & SAFETY

6.1 The concentrate and diluted fluid are alkaline. Precautions are necessary, particularly during dilution, but also in handling and injection, to avoid bodily contact due to splashing, spillage or leakage.  The normal precautions (use of goggles/visor, gloves, protective clothing and the prompt removal of contaminated clothing) should be observed with particular rigour during the handling of the concentrate.

Should the fluid come into contact with the skin it must be washed off promptly.  If it comes into contact with the eyes they should be flushed with cold water for ten minutes and medical attention should be sought.

6.2 To protect third parties from contact with the alkaline fluid, the working area must be tightly screened off during treatment from the public highway (e.g. terraced houses abutting the pavement.

6.3 The solution is aqueous and has no effect on expanded polystyrene or bitumen.

7.   DURABILITY

Evidence exists that silicones used to waterproof walls against rain penetration are still effective after 12 years. In such situations the silicone is applied only to the surface of the wall, but in the damproof course system the course is saturated.  Provided there is no unusual ground water or other contaminant and provided there are no highly alkaline mortars present (as in new repair work) it is envisaged that the process will remain effective as a rising damp barrier for a period in excess of 20 years.

8. DILUTION

Antel Silicone Waterbased D P C Concentrate is diluted with clean water to produce 25 litres of injection fluid.

9.   INSTALLATION

9.1 The course to be injected is chosen so that the position of the horizontal damproof course complies, as far as practicable, with the recommendations of BS Code of Practice 102:1973 (Protection of buildings against water from the ground).  E.g.  The damproof course must be at least 150 mm above ground level and in the case of suspended timber floors must be positioned below the timber joists and/or wall plate.  Internal walls on solid floors are injected as close to the floor as possible.  Complimentary vertical damproof course are positioned, where necessary, to isolate treated walls from the effects of rising damp in adjoining walls or to maintain continuity between horizontal damproof courses at different levels.

9.2 Internal plastering affected by hygroscopic salts is removed from the area to be treated to a height of 300 mm above the maximum level of the rising damp.  Internal skirting, flooring etc. are also removed, as necessary, to expose the area for treatment.  Externally the proposed damproof course line is exposed where necessary by removing any facing material.

9.3 In brickwork, 10 mm or 14 mm holes are drilled to predetermined depths along the selected course.  Two holes are drilled in each stretcher and one in each header, to an average spacing of approximately 120 mm and a maximum spacing of 150 mm.  Drilling may be carried out in the two related horizontal and connecting vertical mortar courses, the holes being not more than 76 mm apart.  Walls 115 mm thick are injected from one side only.  Solid walls of greater thickness are normally injected from both sides, but if access is restricted, can be drilled and injected from one side by a series of injections at increasing depths at increments of not more than 120 mm.  Cavity walls are normally treated from both sides, but if the thickness of the individual leaves permits it, injection may be carried out from one side, at increasing depths.

9.4 Injection of the siliconate solution is carried out at a normal pressure of 350 kPa, but this may be reduced in the case of very porous brickwork.  Nozzles fitted with pressure tight seals are inserted into the drilled holes and injection is continued until complete saturation is achieved and the fluid begins to exude from the substrate.  Where the face of the brickwork cannot be observed e.g. for the double and triple drilling technique described in 9.3 a metered or timed quantity of fluid determined by the initial injection or by prior test upon an exposed section of the section of the second or third leaves, should be pumped into the wall.   After injection, the nozzles are removed and subsequent holes are similarly injected.

9.5 In solid or cavity walls of conventional construction in blockwork or stone the drilling and injection procedure is adjusted to accommodate variations in the density, porosity and structure but in each case the procedure chosed ensures a continuous unbroken band of impregnated material along the length of the wall.

9.6 The treated walls are left for a period of at least 14 days to allow initial drying out.   Internal plastering is applied as outlined in the Replastering Specification.

9.7 Particular care is taken to avoid bridging the injected damproof course.  All holes in the external wall surfaces  are plugged with cement sand mortar coloured to match the existing wall surface.

9.8 In buildings with a history of penetrating damp a spray treatment of Antel Silicone Water Repellent is applied to prevent recurrence.

10.   GENERAL

10.1    The Antel Silicone Waterbased Pressure Injection damproof course system is satisfactory for use to provide a barrier against rising damp in existing solid walls of brickwork, blockwork or stone (excluding flint) up to 600 mm thick, or existing walls of conventional cavity construction, where there is no damproof course or where the existing damproof course has failed.

10.2 Replastering is necessary to retain salts in the body of the wall and to prevent damage to subsequent redecoration.  Replastering must be in accordance with the Antel Replastering Specification.

11.   ACTION WITH RESPECT TO FLOORING TIMBERS

11.1 Where a suspended floor is independently supported on sleeper walls, with an effective damproof course, no injection is necessary.

11.2 Where a suspended timber floor is supported on joists and or a wall plate bearing or imbedded in the wall, there is a possibility of decay, particularly where concealed timbers are in contact with the damp wall. The condition of these timbers should be ascertained and remedial action taken if necessary.

11.3 If damage is limited to the joist ends, the floors may be reformed using sleeper walls or joist hangers to isolate the timbers from the damp walls.

11.4 If the timbers are sound the existing floor may be retained provided the injected damproof course is formed below the timber joists and/or wall plate.

12.   DRYING OUT OF WALLS

A 230 mm solid brick wall affected by rising damp and treated with Antel Silicone Waterbased pressure injection system should normally dry out in 6 - 12 months provided normal heating is used during the winter months.  This period may be exceeded for walls of greater thickness.  Where hygroscopic salts are present adequate drying may not occur, but the replastering system will prevent damage to internal decorations.