Building perimeter system

In combination, a perimeter pocket having a shape of an inverted generally rectangular channel with a top wall and an inner wall depending vertically from the top wall, an outer face of the inner wall having a longitudinal channel bounded at a top and bottom by opposed slots, a connector clip having first and second legs integral with one another and intersecting at a right angle along a line, said first leg of said legs being trapped in said opposed slots, said second leg of said legs being supported as a cantilever by said first leg, the second leg having an inclined through slot, a grid runner end abutting a side of the second leg, a fastener in said inclined through slot and the grid runner end serving as a cam follower along the inclined through slot to lift said grid runner end, the second leg being the sole support of said grid runner end through said fastener when said grid runner end is horizontally displaced relative to said inner wall, an intersection line of said first and second legs being at least as long as a majority of a distance between said slots whereby said first leg substantially resists sagging of said second leg when supporting the grid runner end.