Question
I have an area in front of my house that I want to cover in river rock. The area is about 12x10 ft. Due to the natural downhill slope of our yard, the area I am wanting to cover has a tendency to flood- that's why using bark chips etc has not worked in the past. We previously created a concrete patio but tree roots destoyed that. I have decided to cover the area in river rock. I have a drain in place to take care of water issues. How would you suggest I implement the rock? Put down sand then landscaping cloth then rock?

Answer
River rock is generally rounded and composed of mixed sizes of small rocks from egg size to grapefruit and larger. All you do is set it out in the area you want being sure to cover adequately.

If you are talking about flag stone (large thin flat pieces used for patios), then you need to put down a base of crushed aggregates (Granite stone dust and small chips) and compact it with a small vibratory compactor. Be sure it is level or at most has a 1-2% slope for drainage away from your house. Then apply 1 inch of sand for a setting bed. Screed the sand with a 2x4 (level it) and then apply the stones, tamping and leveling them in place as you go.

You can apply a geotextile separator between the sand and granite if you like to help spread the load of individual stones and reduce shifting but if the stones are large enough this is not required.

Best of Luck

Sean J Murphy
www.seengineering.com
www.amenityarchitects.com

SEI
Southeastern Engineering
Amenity Architects