House was built 2007 - exterior is a mix of hardy plank and cosmetic stone "glued" to concrete. In several places, the adhesive holding the cosmetic rock has failed and the rocks have fallen off. I have the rocks just need advice or directions on how to "glue" them back on plus any prep work I need to do to rocks and concrete walls. Tried several times to hire someone to do this work but I guess they are all too busy for this relatively small project. Thanks