a support runner for use in suspended ceiling grid systems is disclosed with the support runner being useful in ceiling systems having an exposed flange for decorative purposes . the support runner comprises : a lower decorative trim member ; an upper inverted t - runner ; and , an intermediate spline member . the decorative trim member has a decorative lower surface and an engageable upper surface . a spline member is engaged about the engageable upper surface of the decorative trim and extends substantially along the full length of the decorative trim . the upper surface of the spline is an engageable slot . an inverted t - runner is supportingly engaged to the engageable upper surface slot of the spline and extends along the spline a distance sufficiently less than the length of spline and trim members to accommodate heat expansion distortion of the inverted t - runner . when the ceiling system is exposed to heat , the inverted t - runner continues to hold the ceiling panels even though the spline loses structural integrity and disengages the decorative trim .