Question
Sean:

My house is on a gentle slope.  My front yard runs about 200' to the edge of the lake I'm on.  I wanted to lay down an flagstone pad near my house with a path extending from that down to the waters edge.  

Can I lay flagstone (or a thicker stone) on a slope without a border (wood or plastic)?

I do have soem drainage issues in the area I want to lay the larger (10'x15') flagstone pad.  I was thinking about putting soil with grass/moss(?) in between the flagstone  so that the sand would not just wash out.

Is this possible?

Thanks in advance.


Answer
The answer depends on the gradient of the slope and the level at which you place the stone. If its too high water moving across the slope will wash away the material in the joints. If its too steep stones may slide when walked on.
Best bet is to be sure slope is not more than about 5% then excavate the soil where you want the stone and lay down some crushed gravel. Then screed it level and compact it. Add 1" sand setting bed and tamp your stones in place. Make larger joints and fill joints with sod.
Good Luck
Sean J Murphy, LA,ISA, LEED AP
Please check out my blogs and articles on landscape topics like this on my websites.
http://www.seanjmurphy.com
http://amenityarchitects.com