Originally Posted by brendabee
I need advice on a outdoor deck with truss supports. Right now it has a rubber membrane to act as a water barrier to the trusses, and over this is marble slab pieces grouted together. It has been outside 4 years and now the grout is crumbling. It has never been secured to the membrane and was wondering if there is a adhesive that will secure it to the membrane. Then i can grout with a silicone based product between the pieces and hopefully it will be more secure and last longer. I live in Missouri where it goes through winters.
It was not secured to the waterproofing membrane on purpose so that they could move independent of each other, thus not stressing and eventually tearing the membrane. I would clean out the old grout and redo with a more flexible product as you suggest.