RUNNERS and STUDS: Building a Partition Step by Step

A gypsum partition goes up in five steps: mark the wall line on floor and ceiling, fix the RUNNERS (the horizontal tracks that anchor the partition to floor and ceiling), cut the STUDS (the vertical members) and seat them inside the runners at 400 or 600 mm centres, reinforce openings and fixture points and route services, then board both faces with 12.5 mm gypsum and insulate the cavity. Match the stud to its runner size, keep anchor spacing within limits, and leave a small deflection gap at the head. Those three decisions determine whether the wall stays straight and carries its loads for decades.

What runners and studs are, and why they come as a pair

RUNNERS are horizontal sections for installing partitions on the floor and ceiling, and Baghdadi Factory supplies them in three sizes: 5, 7.5 and 10 cm. STUDS are vertical sections that are inserted into RUNNERS and carry the partition covers, meaning the gypsum boards; they come in 4.8, 7.5 and 10 cm.

The runner is a U-shaped track, opening upward on the floor and downward at the ceiling, and the stud nests between its flanges. That is why the stud is marginally narrower than its matching runner: a 4.8 cm stud slides into a 5 cm runner without distortion. Never mix families in one wall. A stud loose inside an oversized runner relies on the board alone for restraint.

Section width sets the finished wall thickness and the service cavity. A 5 cm frame with one 12.5 mm board per face gives roughly 75 mm overall; a 10 cm frame gives about 125 mm, enough for small drainage pipes and deep electrical boxes.

Step 1: Set out the wall and choose the section

Decide three things before cutting metal:

• Clear height from finished floor to the slab or to the suspended ceiling level. Height drives section width: taller walls need wider studs to stay within the lateral deflection limit, and the common criterion in limiting-height tables for ordinary interior partitions is L/240.
• Future loads: kitchen cabinets, wall-hung basins, screens, heavy doors. Each needs backing positioned now, not after boarding.
• Services in the cavity: pipe diameter sets the minimum stud width.

Snap the wall line on the floor, then transfer it to the ceiling with a laser or plumb bob. The two lines should agree to within a few millimetres, because any offset goes straight into the studs. The snapped line is the runner edge, not the wall centreline, so allow for half the finished thickness.

Step 2: Fix the runners

Fix the floor runner, then the ceiling runner. ASTM C754 limits anchor spacing to 610 mm (24 in), with an anchor no more than 50 mm from each runner end and each splice. On concrete, use shot-fired nails or expansion anchors giving at least 25 to 30 mm of real embedment. Under a suspended ceiling, anchor the runner into the ceiling's carrying members, never into the gypsum board alone.

Any acoustic or damp-proof strip specified under the floor runner goes down before the anchors, not after. At abutting walls, fix the first stud directly to the concrete or blockwork at the same spacing; it becomes the end frame of the partition.

Check the floor runner with a spirit level at least 1 m long before driving the remaining anchors; any wave in the screed shows up in the finished board line.

Step 3: Cut, seat and space the studs

Measure between the webs of the floor and ceiling runners and cut each stud 10 to 15 mm short. That gap is deliberate: it lets you tilt the stud in and rotate it upright, and it leaves room for slab deflection. A gypsum partition is non-load-bearing and must never become a prop.

Space studs at 400 or 600 mm centres. A standard 1200 mm board suits both, so board edges always land on a stud. Use 600 mm for typical heights, and 400 mm for tall walls, single-layer boarding needing extra stiffness, or walls receiving ceramic tiles. The Saudi Building Code (SBC) sets the general requirements for non-load-bearing interior partitions; the section's limiting-height table remains the detailed reference by width and spacing.

Orient every stud's open side the same way, towards where boarding starts, so the first board screws into the solid flange. Secure each stud to both runners with 3.5 × 9.5 mm wafer-head screws or a crimping tool.

Step 4: Openings, backing and services

• Door openings: place a stud each side of the opening. For heavy doors or openings wider than 1 m, double the stud or box it with an inverted runner, and fix the door frame into that box. Form the head from a runner offcut with flanges snipped and bent 90° down at each end to screw into the jamb studs, and add a short cripple stud above the head to carry the board joint.
• Hung loads: fit horizontal backing between studs at the exact fixture height, either a runner offcut or 18 to 20 mm treated plywood. Basins, cabinets and screens above 15 kg need it.
• Services: run cables through the service holes in the stud web where provided, with a grommet at the metal edge. Do not enlarge holes by hand; that weakens the section where it is most stressed.
• Corners and junctions: at every L corner and T intersection, add a stud so each board has a flange to screw into.

Step 5: Board and insulate

Complete the first face before starting the second. For a single 12.5 mm board on light-gauge steel, use 3.5 × 25 mm drywall screws at 300 mm in the field and 200 mm along edges, never closer than 10 to 15 mm to a board edge. The screw head should sit just below the paper surface without cutting it; a screw that breaks the paper holds nothing.

Board the first face with vertical joints on stud centrelines, place the cavity insulation, typically 50 mm mineral wool or whatever the acoustic or thermal specification calls for, then board the second face with joints offset from the first by at least one stud. The offset prevents a continuous crack line through both faces.

Hold the bottom board edge about 10 mm off the floor to avoid wicking moisture; the skirting covers it. Wet areas need moisture-resistant boards. In corridors and separating walls, two layers of 12.5 or 15 mm per face may be required to reach the fire rating, and there the SBC governs the separation requirement, not the board alone.

Common site mistakes

• Anchoring runners wider than 600 mm to save time, so the wall line waves under the first push.
• Cutting studs to the full height so they act as columns, pick up slab load and crack the board at the ceiling.
• Pairing a 7.5 cm stud with a 10 cm runner because stock ran out, so the board ends up doing the structural work.
• Skipping backing, then trying to hang a basin on hollow-wall anchors.
• Driving screws closer than 10 mm to the edge so the board crumbles.
• Forgetting to offset the second-face joints.

The practical summary: pick the section family from wall height and the services it must carry, anchor runners at 600 mm maximum, cut studs 10 to 15 mm short and set them at 400 or 600 mm, build backing and reinforce openings before boarding, then screw boards at the spacings above with staggered joints. Follow that sequence and the partition comes out plumb and carries what gets hung on it for years. For the RUNNERS and STUDS sizes available, Baghdadi Factory can be reached on WhatsApp at +966596046900 or by email at contact@baghdadi.sa.