Carrying Long Board on Roof vs Bed

has anyone carried 8'-10' long board on the roof of a full sized cab? was it safe on the highway? I have a perfectly good roof rack with cross bars and don't want to buy bed rail mounted cross bars if I can just use the existing ones.
thanks

 

i have a thule roof rack and its works fine, cannot speak to the factory rack, but i don't see why it wouldn't work as well

 

I have a tailgate pad for mine. Put the nose up by the cab in the bed and the tail hangs over the tailgate w/ the fin facing up. I put a ratchet strap over the board and hook on the d-rings to make sure it doesnt go anywhere. Cost for the tailgate pad was probably 25-30.00.

 

In Hawaii I mostly see roof/bed racks or just out over the tailgate....rarely ever oem roof racks with surfboards/sup, and always bed rack for one man canoes.

 

It’s safe or you could get a Dakine tailgate pad. I have one it is great. Fast and super easy to put the board in the bed of your truck