As mentioned last year, that area was supposed to be rooftop outdoor jail/children-play-area for the non-profit child care facility,... hence the jail bars!
http://urbantoronto.ca/forum/thread...-riocan-quadrangle.17901/page-12#post-1130707
Just figured it out,... I was looking at their original plans and thought they had to fix a leak because the dollarama underneath is always leaky,.... but they recently revised their plans,.... and that rooftop will now have a 2 storey structure added on top of that rooftop (notice they seem to be setting up wooden squares to form cement columns) to host part of the daycare and family services community space (obviously relocated from other part of complex - likely freeing that space for more retail, hmmm,....). The outdoor jail/children-play-area will move slightly north temporarily to where the pile of fencing are in your photo - then permanently on rooftop of 3 storey daycare facility at north end where current loading docks are.
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