Unity 5 - Cloth falling through floor

Hi, I am trying to simulate a rug on a floor that the player can interact with. I created a cube floor with box collider, a player with capsule collider, and a cube scaled to resemble a flat rug.

I then added the cloth component to the rug and added the player's capsule collider to the collider list in the cloth component. So it works great when the player is colliding with the cloth, but because the floor is not a capsule/sphere/conic-capsule, I can't add the floor to the collider list as so the cloth falls through the floor. Is there any work around solution?

I've watched tutorials of the old skinned & interactive cloth methods but read that they are cpu intensive so it wanted to use just the 'cloth' component instead. I've tried adding a rigid body and box collider to the cloth / tried using multiple small child box colliders with spring joints / hugely massive capsule collider under the floor... but none really work well except the last one but that was a pretty silly solution.

Any suggestions would be great thanks!