The situation. 2011 built home Seattle lots of shade. Very clay heavy soil with plasticy landslide retention netting over the top throughout the property. Sod seems to just have been laid over the top. Pretty patchy grass where it has survived. Established grass have shallow rooting. Property on a slight slope, water drains off through top few inches of soil creating nasty sloppy clay conditions. How do we create better soil conditions to establish better rooting? Do we worry about adding top and having it simply slide away do to semi impermiable layer underneath?