Saw cut the extremities of the repair locations to a depth of at least 10 mm to avoid feather edging and to provide a square edge. Break out the complete repair area to a minimum depth of 6 mm up to the sawn edge. 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 laitence by light scabbling or grit blasting.
Oil and grease deposits should be removed by steam cleaning, detergent scrubbing or the use of a proprietary degreaser. The eff ectiveness of decontamination should then be assessed by a pull-off test. Expose fully any corroded steel in the repair area and remove all loose scale and corrosion deposits. Steel should be cleaned 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 its surface.

Substrate Priming

The substrate should be thoroughly soaked with clean water and any excess removed prior to commencement. A slurry primer should be prepared consisting of 1 volume Vetobond PB434 to 1 volume clean water to 3 volume fresh cement. To obtain a smooth consistency, the cement should be blended slowly into the premixed liquids. The slurry primer should be stirred frequently during use to offset settlement.

The slurry primer should be scrubbed well into the surface of the concrete. Avoid applying too thickly and avoid ‘puddling’.

The repair mortar, topping or render must be applied on to the wet slurry primer. If the slurry primer dries before application of the mortar, it must be removed and the area reprimed before continuing.

In exceptional circumstances, e.g. where a substrate/repair barrier is required or where the substrate is likely to remain permanently damp,contact Saveto Technical Support.

Vetobond PB434 mortars, toppings and renders should not be applied when the temperature is below 5ºC and falling. Neither should they be exposed to moving water curing application. Exposure to heavy rainfall prior to the final set may result in surface scour. If any doubts arise concerning temperature or substrate conditions, consult the local Saveto office.