Older roofs, tighter lots
Houses in the Fan were mostly built between the 1890s and the 1920s, and a lot of those roofs still have the original skip sheathing under one or more shingle layers added since. That changes both the tear off plan and the decking work on a full replacement, since skip sheathing has gaps that need solid decking added before a modern shingle can be nailed down correctly.
The narrow lots and shared walls common to the Fan also limit access. Material staging and tear off debris removal both take more planning here than on a house with a wide driveway and open yard.
Mature trees over old roofs
The large oaks and sycamores that give the Fan its canopy are decades, sometimes a century, older than most trees in Richmond's newer subdivisions, and their limbs reach well over the rooflines below. A limb that has grown against a roof edge for twenty years does real, gradual damage even without ever falling.
Root systems from these same trees can also affect porch foundations and low roof sections on rowhouses, which is part of why a combined roof and tree look at a Fan property often turns up more than either trade would catch alone.
Working around historic district rules
Roof replacement in parts of the Fan falls under Richmond's Old and Historic Districts review, which can affect shingle color and, in some cases, material choice on street facing slopes. That review adds a step to the permit process that a homeowner should plan for before scheduling a tear off.
Rear facing slopes not visible from the street generally face less scrutiny than the front, which sometimes gives a homeowner more flexibility on cost or material for the back of the house even when the front is constrained by district guidelines.
Access and staging on rowhouse lots
With little to no side yard between houses in much of the Fan, material delivery and debris removal both need to route through the front of the property in most cases. Scheduling a tear off here usually means coordinating around on street parking as much as around the weather.