1. Nailing Down Wide door casings can hold the end of baseboard back away from the studs. A 2x6 block next to the door provides firm nailing.
2. Packing Out Wall switch plates also can crowd the door trim. Help your electrician and place a double 2x block here for the switch box.
3. Joining Up Where chair rail will dead-end against door casing or cabinetry, place a block for nailing the end of the trim piece.
In production building, it’s called “pick-up framing”—a dedicated crew follows behind the house framers installing blocking in all the right places. Custom builders have to work the same process into their schedules.