If a crawlspace ranges from 4' to 7.5' in height is it possible to make it into a basement?
Yes ,but the rule of thumb would be about 4 feet or less to be
called a crawl space. This is quit a structual endevor requiring
excavation ,pinning of the newly pored curb footing and rebar to
create the needed support.In most cases if your looking to add more
then 2 feet it isn't worth the expense.