After applying a base coat such as hpx or render aid modern monocouche renders are applied in two passes and come in a bag pre coloured so all you need to do is add clean water and mix. After the two passes have been applied and ruled flat you need to wait before its time to use the scratcher, when scratching back you need to aim to remove the top 2mm to create the final finish. Remember after you’ve scratched back brush the wall with a soft clean brush to remove any dust.