The grouting on my patio is looking a bit pathetic so I've raked it all out in preparation for some new grout. My mate's visiting this weekend and he's a builder. He said it's best to grout the patio with a mortar like grout so it sets hard (like brickwork). However, looking around on the web and most people suggest using the sort that you brush in and leave it to go hard. Anyone done their patio lately?