Our pressure treated deck is 36 feet by 12 feet with the boards running
in the long direction (parallel to the house). The previous owner
ruined the boards so I want to replace them.

It occurs to me that I could put 12 foot boards over top of the
existing decking and have a seamless deck with the boards running in
the short direction (perpendicular to the house). I'd leave gaps
between the boards for drainage. I could even remove some (1/2, 1/3) of
the old boards to improve drainage if necessary.

The deck will be a bit higher but it is already a step down from the
house so that won't be a problem.

Is this done? Are their hidden problems waiting to bite me if I install
new 5/4 x 6 boards on top of and perpendicular to old ones?

Thanks
gb