Light partition walls and plasterboard cladding

A light partition wall is a non-load-bearing wall that divides a room without bearing the storeys above. It is built as a frame — vertical studs between a base and top rail — clad with boards on both sides and usually filled with insulation in the cavity. It sounds simple, but it is a wall whose properties (sound, fire, hanging of things) depend entirely on how the frame and cladding are assembled.

The frame can be timber (typically 45 × 70 or 45 × 95 mm studs) or light-gauge steel (galvanized profiles). Steel frames are light, square and do not rot, and are increasingly used indoors. The profiles have two roles: a horizontal rail (track) in floor and ceiling, and vertical posts (studs) that snap down into the rails.

• 01Steel channel (Knauf 'UW', Gyproc 'S-profile'): the horizontal bottom and top channel that the studs stand in.
• 02Steel stud (Knauf 'CW', Gyproc 'R-profile'): the vertical post; supplied in widths such as 45, 70, 95 and 120 mm — width is chosen based on wall height and requirements for sound/services.
• 03Timber frame: 45 × 70 or 45 × 95 mm; requires dry, square timber so the wall does not work and crack at the board joints.
• 04Wider profile/batten provides room for more insulation and a larger cavity — and thus better sound.

Column spacing (c/c) is not free: it is tied to the board format, so the long edges of the boards always hit a column. A 900 mm board fits c/c 450 mm, a 1200 mm board fits c/c 600 mm (see the article on centre-to-centre spacing). For ceilings, high walls and tile bases, the tighter c/c 450 mm is often chosen for stiffness.

The number of board layers is the most important factor in wall performance. One layer of plasterboard on each side is the simplest wall. Two layers on each side (double cladding) provide more mass and close the joints because the layers are offset so board joints never lie over each other — this significantly improves both sound and fire performance.

• 01Single lining (1 + 1 layer): simple, not sound or fire-rated walls.
• 02Double cladding (2 + 2 layers): offset joints, better sound and fire — standard for party walls and fire-separating walls.
• 03Staggered/double frame: two separate rows of posts on separate tracks, so the two wall sides do not share a post. Breaks the sound path through the frame (see the sound article) and is used where high sound requirements are set.
• 04Drywall thicknesses: 12.5 mm is standard; 15 mm is used for fire ("fireline") and robust/hard boards. Choose board type according to the requirement, not by what happens to be on site.