I am adding to the house using an exiting concrete block foundation from a porch.  I ripped out the concrete slab and removed the fill so I would have a crawl space.  I plan on punching through the concete block wall into the adjoining basement for access.  Do I need to ventilate this crawl space to the outside also?  The basement is dry and  fairly temperate throughout the year.  Also,  the house sits on a 6×6 sill, I assume  this would be stout enough to carry the load from above  after I knock out the block for a crawl space opening?  Its a gable wall that I’m working on.   Thanks in advance for any advice.