There is about a 6' linear section of grout between my waterline tile and precast concrete coping that is cracked enough to let water in. There must have been some settling to cause this as the coping sounds hollow underneath along this section when I knock on it. I'm thinking the crack needs to be sealed.
I read on this site that polyurethane caulking is recommended, but when I went to Lowes I only found one thing actually labeled as polyurethane and it didn't get too great of reviews when I looked it up online when I got home. Since I'm not familiar with caulking, I'm wondering if anyone has a particular product and brand that they'd recommend in my situation? I want to do it right the first time. In case it matters, we also have a Home Depot close by so I can shop there too if that's the only place I can find something.
Thanks for your help!