nogging

Nogging is the infill material, timber, brick, or other material, packed between the vertical and horizontal timbers of a timber frame to provide structural support and weatherproofing. In its primary carpentry sense, it refers specifically to the horizontal wooden beams that run between vertical posts or studs, creating a grid that prevents racking (the tendency of the frame to distort under lateral stress) and gives the structure rigidity.

In traditional half-timbered construction, nogging serves a dual purpose: it strengthens the wooden skeleton by distributing loads across the frame, and it closes the gaps between timbers to keep out wind and weather. The term encompasses both the structural function and the material used to fill it. Brick nogging, common in Georgian and Victorian building, sits flush with or recessed behind the timber grid. Timber nogging, more typical of medieval and Tudor work, comprises horizontal rails mortised into the uprights or secured with pegs.

Nogging in frame design

The spacing and dimensioning of nogging depends on the load case and span. In heavy timber frames, nogging might be 6 to 12 inches deep (measuring perpendicular to the face of the frame) and spaced every 3 to 4 feet vertically. The horizontal members themselves are typically 4 to 6 inches deep and 3 to 4 inches thick, mortised at both ends into the vertical posts. Inadequate nogging or decay in the timber creates weakness: the frame can rack, and water penetration accelerates rot in the structural timbers above and below the gap.

The name likely derives from the notion of filling or stopping up (related to the verb 'nog', meaning to fill or block). In modern timber-frame carpentry, the principles remain: preventing racking and closing the envelope are essential. Modern timber framers often use diagonal bracing or rigid sheathing instead of nogging, but the horizontal members that tie the frame together are still sometimes called nogging rails.

When inspecting or repairing half-timbered buildings, the condition of nogging is critical. Missing or crumbling brick nogging exposes the frame to water and pest damage. Timber nogging that has dried and separated leaves cracks that lead to drafts and decay. Replacement nogging must match the original material and technique, using modern materials or methods in historic work can trap moisture and cause the structural timbers to deteriorate faster.