Step 1 – Substrate Suitability Check
Ensure that the pebble-dashed wall is stable and secure by knocking the existing substrate with a shovel or hammer. Loose pebbles should be removed, and any areas of crumbling pebbledash should be stripped back completely.
Step 2 – Priming the Substrate Prior to OCDC
Apply a layer of EWI-310 Universal Primer to the substrate. This will increase the adhesion between the pebbledash and the OCDC, and ensure that the substrate is stable.
Step 3 – Applying OCDC
OCDC should be mixed with 5 litres of water per 25kg of the dry mixture in a large bucket using a mechanical mixer. In order to level out the wall, apply the first pass of OCDC (up to 20mm) to the areas where the Pebbledash has been stripped back.
Once the first pass has set the second pass should be applied to the entire substrate, taking the total thickness up to a maximum of 50mm. Fibreglass Mesh should be embedded within the second pass of OCDC to enhance its tensile strength. A plastic, metal or felted float should then be used to create a smooth surface.
Step 4 – Applying the Decorative Finish
Once the OCDC is completely set, you are ready to apply your decorative finish. At this stage, you can choose to either render or paint the substrate.
For painting the substrate, we recommend using the EWI-005 Silicone Paint. This will create a breathable, waterproof surface that is resistant to environmental pollutants.
When rendering the substrate, we suggest using a silicone-based render, such as our EWI-075 Silicone Render. This is highly breathable and hydrophobic, with self-cleaning capabilities to ensure a clean surface for years to come.