Start below the surface
Durham's clay-heavy Piedmont soil and rolling terrain toward the Eno River watershed mean base compaction, drainage slope, and joint spacing decide long-term performance more than the finish coat does.
Build a complete scope
- What the existing flatwork is doing, which shows how this lot has moved
- Subgrade handling under clay that holds water instead of draining it
- Whether new hard surface redirects runoff on a sloping lot
- Mix, reinforcement, joint spacing and curing method, stated explicitly
- How new work meets century-old walks and foundations, plus warranty
Durham context
Piedmont red clay is the subgrade under nearly every pour in Durham, and it behaves in the way that gives flatwork the most trouble: it holds water instead of draining, then swells and shrinks through the seasons, so a driveway or patio placed without addressing what is beneath it will move no matter how well the surface was finished. Rolling watersheds make the siting question real, because adding impervious surface on a sloping lot changes where storm runoff goes and can send it toward a neighbor or a stream corridor. The city's age adds a third consideration that new-construction advice misses: in the streetcar neighborhoods and the older tobacco and textile districts, existing walks, drives and foundations were built to earlier practice, and new concrete placed against them has to accommodate that rather than assume a matching detail. Mature roots both lift old slabs and complicate excavation for new ones.