Sill plate
Timber Sills:
– Historic buildings feature large, solid timbers as sills.
– Sills frame corners, carry bents, and rest on stone or brick foundations.
– Sills support wall framing and floor joists.
– Some U.S. historic buildings have floor joists directly on the foundation with a plank or timber sill atop.
– Timber-frame buildings sometimes have posts directly on the foundation with interrupted sills between them.
Stick Framing:
– Modern wood construction uses sills of sizes 2×4, 2×6, 2×8, and 2×10.
– Sills are made of treated lumber and anchored to the foundation with J-bolts.
– Building codes mandate sills be 6 to 8 inches above grade to deter termites and prevent rot.
– Sill plates prevent buildings from shifting during storms or earthquakes.
Automobiles:
– Sill plates in automobiles are located beneath the door.
– Automobile sill plates may display the vehicle’s make or model.
Naval Architecture:
– In naval architecture, the sill refers to the lower horizontal plate height.
– Doors and access openings are fixed above the sill in naval architecture.
References:
– “Framing Basics” by Rick Peters discusses sill plates.
– Simon Tolson’s “Dictionary of Construction Terms” defines sill plates.
– Richard Soule and George Howison’s work mentions ground plates in timber frames.
– Jack A. Sobon’s book provides a graphic guide to historic American timber joinery.
– John Burrows’ “Canadian Wood-Frame House Construction” is a resource on sill plates.
A sill plate or sole plate in construction and architecture is the bottom horizontal member of a wall or building to which vertical members are attached. The word "plate" is typically omitted in America and carpenters speak simply of the "sill". Other names are rat sill, ground plate, ground sill, groundsel, night plate, and midnight sill.
Sill plates are usually composed of lumber but can be any material. The timber at the top of a wall is often called a top plate, pole plate, mudsill, wall plate or simply "the plate".