Backyard patio I've got scheduled in the next couple of weeks has an existing slab. New construction (+/- 3yrs old) with no sign of cracks or settling. The new patio will extend about 4-5 feet past the edge of existing concrete slab. I'd like to glue my soldier course (NO parallel glue lines - might help that part of slab drain water?) using a thicker paver and set the interior pattern on sand. Patio outside of existing slab would be on traditional compacted base. I'm trying to save myself the expense/trouble of taking up existing concrete. It can't be more than a couple hundred square feet but if I can save on labor, dump fees, extra excavation and extra base.. I've done about a dozen paver jobs - will follow established practices to the letter. Anyone see any problems with this? Thanks.