O.P. could put matching or perpendicular flat PTs under the grate, and bolt the sleepers and those things hard together. Short carriage bolts from the top, nuts on the bottom. Once a year you tighten up the nuts (assuming it's really accessible underneath) to take the rattle out.Yes exactly, so he can put sleepers with decking he will need a minimum of 2.5" of clearance. I could be on the wrong track here, but it's something to consider.