Brushes Inside Props? "node without a volume" error

I figured out the reason I was getting the "WARNING: node without a volume" error is because I had two very large propper-made props colliding with player clips I had made for them. I had tried making collisions with propper for these props but they absolutely sucked, they were treated like a solid square, therefore I put a player clip right on the model. I deleted just the player clips on both props and the compile worked without the node error, but I absolutely need collisions to work with these props.

I have put ladder through floors before and that works fine, why can't I do this?

All my props are static for anyone that asks

Brushes Inside Props? "node without a volume" error