The entry to our neighborhood has two walls with signs approximately 25 years old. Each wall has about 750 ft2 of surface area. They are built on a concrete foundation with concrete blocks originally covered with mortar wash and stucco. Sometime in the past an elastomeric coating was applied. The horizontal top surfaces have hairline cracks and appear to be a main source of water intrusion. There are quite a few visible places on the vertical wall surfaces where the elastomeric coating has bubbled and can be easily removed with a razor knife. The block appears to be generally sound underneath and has not started to crumble. There is mildew along quite a few of the block lines visible from the surface of the elastomeric coating. The coating on the majority of the vertical surfaces, however, appears to be adhering well. Two general methods of repair have been suggested: 1) power wash, scrape and rotary grind all coating that is not adhering which can be found and applying another coat of elastomeric. 2) scrape and rotary grind all coating that is not adhering which can be found, prime, apply a fiberglass base and then applying a non-elastomeric coating system. There may be other methods as well. What in your experience is the best way to restore the walls or have they reached the end of their useful life?

I just got a Ryobi AG 4531G angle grinder and some 4 1/2 masonry cut off discs. When I opened the angle grinder up, I see that they say to never use cut off or type 1 discs. I have a 7 1/2 inch circular saw I've been using to cut concrete ( a very sloppy foundation job that a local contractor did), but need to get into some tight corners that I thought an angle grinder would do. Will this not work? I'm ready to return the angle grinder if I can't use it for this.