you might try a product called goooff? not sure on the spelling but found it at canadian tire or perhaps local hardware store. Small yellow tin with red lettering. It is a xylene based mix product which seemed to work well for me.
form the edges with 1x4 spruce staked to a string line with 1 inch slope per 10 ft either away from house or away and cross sloped, good gravel/sand base of 8 inches and don't let anyone talk you out of 6x6 9over9 wire mesh to hold it together over time....... the ground moves so hold the...