To repair cool deck flaking (not cracks in concrete):
All of the flaking or cracked texture needs to be removed. This is accomplished by using a scraper in conjunction with a high pressure washer. If the flaking is excessive and severe it may not be necessary to use the pressure washer. Bottom line is the old patch needs to be removed to expose the underlying cement. The cement also needs to be cleaned and all loose dirt or sand needs to be removed. On areas where the patch is solid and sticks firmly to the cement the sides of those areas should be smoothed at 90 degree angle to prepare for the new cool deck coating.
After the removal of the old texture, wash off the exposed concrete and make sure all loose material is also removed. Using a mixture of half muriatic acid and half water, scrub the exposed cement to "score" the cement and also to clean off contaminants. After 3 or 4 minutes completely rinse off concrete and scrub with a hard brush to ensure all acid is removed. Again, a high pressure washer is always recommended for the best removal of all acid and residue. I let the concrete dry completely before moving on to the next step. I've found that any moisture remaining in the concrete will cause the new decking to flake and peel within a few years.
Several products exist on the market for cool decking. The easiest is a product I've found is by a company by the name of E-Z Patch. My best advise is to use the internet to find a store that carries the product. The coating product is applied directly to the concrete with a roller. Two coats are typically required. Dry time is normally 3 to 4 hours depending on the day.