Fairmount craftsman bungalows. Arlington Heights Tudors. Near Southside four-squares. Pier-and-beam foundations, knob-and-tube wiring, lath-and-plaster walls, and original architectural character worth saving. Here's why historic Fort Worth renovation is 6th Ave's specialty — the construction realities of pre-1970 homes, how the city's preservation review actually works, and the approach that does justice to these houses.