We have a approximately 200 sq ft patio that is fenced in. We removed the old wood deck and discovered more dirt than we expected. We have no place to take the dirt and it would be so much more work than we had planned if we should remove it. We had expected to have to lower it some for flagstone, but not the amount that we have found. How can we border the fence to prevent the sand between the stones from flowing out, with the flagstone above the side walk level. The sidewalk is on the outside of the fence. Hope I have made myself clear.

To edge that area against the fence I would use the standard felt expansion we use when we pour concrete. Its obviously made for being out doors. It comes in 10' lengths and 4" or 6" wide. It will also make a nice black line for an edge. Also it can be tacked to a wood fence to hold its position and then it can also be used as a gage for the heights/slope you want.

You nay find it at the big box stores, if not then a concrete masonry supply house. They also make edging to tack into the ground for dry laid walks/patios.