Timber partitions: In a common wooden partition, the “sill” refers to which member?

Introduction / Context:
Wooden partitions and frames are defined by specific members: sill, head, studs, rails, and braces. Correct naming is important for drawings, bills of quantities, and onsite instructions.

Given Data / Assumptions:

• A typical stud-and-rail timber partition frame.
• Standard nomenclature applies.
• Focus is on identifying the sill member.

Concept / Approach:
The “sill” is the lower horizontal member that rests on or is fixed to the floor and carries the studs above. The “head” is the upper horizontal member; “studs” are the verticals; “rails” or “noggings” are intermediate horizontals; end verticals are sometimes called posts.

Step-by-Step Solution:
Define the sill: bottom horizontal frame member.Differentiate from head (top), intermediate rails, and vertical posts.Select the correct description.

Verification / Alternative check:
Timber framing guides and carpentry manuals consistently name the bottom member as the sill or sole plate.

Why Other Options Are Wrong:
Vertical end member: that is a post or stud.Upper horizontal: the head, not the sill.Intermediate member: a rail/nogging.Diagonal brace: different function entirely.

Common Pitfalls:
Confusing “sill” with “window sill”; in partitions, sill refers to the lower frame piece along the floor.

Final Answer:
Lower horizontal member of the frame.