I was going to use a material similar to what RJ showed, but I was going to apply it manual with a small stiff bristle brush (hint, a tooth brush works great for this). If the goal is to protect the area where water can get it, that is where I want to focus. Also, by using a brush, I think I can be more assured that surface tension won't keep the material out of the crack. With two people, it is a pretty simple job; one pulls the other person dabs with the brush.