The housing bubble burst will force the Miami-Dade County Building Department to boost fees to keep adequate operating reserve funds, director Charles Danger said. The collapse of the local construction industry has cost the department $14.5 million during the past two years, leaving only $2.2 million in its reserves, he said. More than 100 staff members have already been cut from the department’s ranks. Builders said they don’t love the proposed fee hike but accept its necessity, and would like the increase phased in to soften its blow. Should the proposed hike pass, fee payers would receive declining discounts from 70 to 10 percent over the next five years. They’d begin paying the full new charge in 2014.