I have a block patio and it slops quite badly 5m x 6m. I wish to build a deck and an L shaped seating area out of blocks which will then be rendered and painted. Should I dig the patio up first and dig foundation trenches? or should i level it out and use it as the foundations?
yeah dig it up and put a foundation in. just dig it down till you get to a stable footing and obviously making it wide enough for the blockwork. leave a bit of scarcement either side,ie, if it's nine inch block then have four inch of concrete remaining either side.