This bed is easy to put together.  I bought it to go over a pop-up trundle.  It had plenty of room for the trundle.  The platform sits 16" from the floor. I believe the underside is 15" from the floor.  The crossbars feel a bit flimsy and I think support for a large person would be questionable.  Mine came with one crossbar that needs replacing.  Everything else was in perfect condition.