Preparation
Clean the surface and remove any dust, unsound or contaminated material, plaster, oil, paint, grease, corrosion deposits or algae. Where breaking out is not required, roughen the surface and remove any laitance by light scabbling, grit blasting, scabbling or by needle-gun to form a good key.

Oil and grease deposits should be removed by steam cleaning, detergent scrubbing or the use of a proprietary degreaser. The effectiveness of decontamination should then be assessed by a tape pull-off test.

Expose fully any corroded steel in the repair area and remove all loose scale and corrosion deposits. Steel should be cleaned back to a bright condition paying particular attention to the back of exposed steel bars. Grit-blasting is recommended for this process.

Where corrosion has occurred due to the presence of chlorides, the steel should be high pressure washed with clean water immediately after grit - blasting to remove corrosion products from pits and imperfections within the surface.

The prepared area should be blown clean with oil-free compressed air.

Reinforcing steel priming
Apply one full coat of Dulux Metalshield Cold Galv Primer to all exposed reinforcing steel and allow to dry before continuing. If any doubt exists about having achieved an unbroken coating, a second application should be made and, again, allowed to dry before continuing.

Substrate priming
The substrate should be thoroughly soaked with clean water and any excess removed immediately prior to priming. Any areas of the substrate which dry out before application of the primer must be re-dampened before continuing.

Apply Dulux Avista Resurfacing Primer diluted (1 part modifier and 3 parts water) onto a dampened surface ensuring complete coverage particularly around the edges.

Apply the topping whilst the Dulux Avista Resurfacing Primer is still tacky. The priming operation must be repeated if the initial coat has dried out.

Mixing
Care should be taken to ensure that Dulux Avista Concrete Patch Repair Compound is thoroughly mixed. A forced action mixer is essential. Mixing in a suitably sized drum using an approved spiral paddle in a slow speed (400/500 rpm) heavy duty drill is acceptable for the occasional one bag mix. Free-fall mixers must not be used. Mixing of part bags should not be attempted.

Place 2.8 - 3.5 litres of drinking quality water into the mixer and, with the machine in operation, add one full 20 kg bag of Dulux Avista Concrete Patch Repair Compound and mix for 3 minutes until fully homogeneous. Note that powder must always be added to water.

For larger areas, water should be mixed 50:50 with Dulux Avista Resurfacing Primer, for example, 1.75L of water and 1.75L Dulux Avista Resurfacing Primer to yield a 3.5L mix per 20kg bag.

Application
The mixed Dulux Avista Concrete Patch Repair Compound must be applied onto the primed surface before it dries. Areas which dry too soon must be scrubbed clean and reprimed exactly as described above before continuing.

Apply the mixed Dulux Avista Concrete Patch Repair Compound onto the primed substrate as soon as possible after mixing. The mortar should be applied evenly by trowel and tamped in place with wood float to ensure full compaction. Thoroughly compact the mortar around any exposed steel reinforcement. Dulux Avista Concrete Patch Repair Compound can be applied up to 40 mm thickness in single applications.

Build-up
Sections greater than 40mm thickness can be achieved by application of multiple layers should be scratch-keyed, covered with polythene sheeting secured at the edges, and allowed to set for a minimum of 7 hours (at 23°C) before continuing. Dampening down as described above, and a further application of Dulux Avista Concrete Patch Repair Compound may proceed at this time.

Finishing
Dulux Avista Concrete Patch Repair Compound should be struck off to the correct level and finished with a steel trowel to fully close the surface. The completed surface should not be overworked. If overcoating with resurfacing product, strike off with a straight edge and then finish with a wooden float to provide a good key.

Low temperature working
In cold conditions down to 10°C, the use of warm water (up to 30°C) is advisable to accelerate strength development. Normal precautions for winter working with cementitious materials should then be adopted. The material should not be applied when the substrate and/or air temperature is 10°C and falling. At 10°C static temperature or at 10°C and rising, the application may proceed.

High temperature working
At ambient temperatures above 30°C, the material should be stored in the shade and cool water used for mixing.

Curing
Dulux Avista Concrete Patch Repair Compound is a cement-based repair mortar. Dulux Avista Concrete Patch Repair Compound must be cured with Hessian or plastic immediately after finishing.

Overcoating with protective finishes
Dulux Avista Concrete Patch Repair Compound is extremely durable and will provide an excellent hard wearing surface to the repaired locations. A decorative resurfacing finish may be applied over the repair area after approximately 4 - 6 hours.

Cleaning
Dulux Avista Concrete Patch Repair Compound and Dulux Avista Resurfacing Primer should be removed from tools, equipment and mixers with clean water immediately after use. Cured material can only be removed mechanically.