Hi-I'm wondering if you can help with my query? Several tiles on my second floor, suspended concrete balcony have lifted up over the years. I have removed the raised tiles and several others around them that have loosened. I have replacement tiles for the area and will remove previous adhesive etc before retiling. The balcony gets a lot of weather - I'm hoping to get some advice on whether I need to weatherproof or prime the concrete, and what adhesive and grout to use? Thanks in advance!

