We had a problem with the grouting in our patio so I ask the landscaper who does a lot of work in our garden. He suggested we use joint-it as he had used it before and said it was really good.
He spent the day taking out our old cement type grouting and came back the next day with the the joint-it product. We were more than impressed with the result and it has now been in for about 18months. I have cleaned the patio a couple of times with power washer and it has remained perfect.