Technical guide · Pandaboard

Painted T-Bar Grid: Installation, Spacing and Storage

A painted T-bar grid is the exposed metal frame that carries ceiling tiles. It is built from T24×38 main runners, T24×26 cross tees and an L25×25 wall angle, roll-formed from 0.30–0.45 mm galvanized steel strip with a polyester paint finish (sizes confirmed on order). Hangers go at 1200×1200 mm and no more than 300 mm from a runner end; runners are cambered 1/200–1/300 of the short span; cross tees sit at the tile width, usually 600 mm. Two rules decide how long the grid lasts: every cut end gets anti-rust paint, and a hanger clip is never replaced with wire.

The painted T-bar grid is the load-bearing and forming framework of an exposed-grid ceiling, roll-formed from galvanized steel strip and finished by electrostatic powder coating. It is not a consumable but a structural component that governs the flatness, safety and service life of the ceiling. This document covers its types, connection details, leveling and storage, and serves as the general accessory manual for the ceiling range.

Safety noticeMost ceiling collapses originate in the grid: hanger rods replaced by wire, tabs not pushed home, joints concentrated at one point, and additional loads hung directly on the grid. The control values in this document are mandatory and may not be replaced by site habit.

01Key specifications and suitability

Suitable

• Exposed-grid ceilings in offices, schools and hospitals

• Malls and public corridors where the grid stays visible

• Ceiling refurbishment that keeps existing light positions

• 600 module ceilings in mineral fiber, fiberglass or gypsum tile

• Service corridors where the void is opened often

Not suitable

• Outdoor or semi-outdoor areas exposed to rain

• Spaces held above 70% RH without a corrosion-protected grid

• Workshops with acid or alkaline mist — use aluminum or stainless framing

• Concealed, curved or bespoke ceiling shapes

• Hanging luminaires or ducts directly from the grid

02Before you start

2.1 Site conditions

• Services above ceiling：MEP, sprinkler, ductwork and cable tray installed, pressure-tested and insulated before the grid goes up

• Datum：Site +1.000 m level handed over; finished ceiling line marked on all surrounding walls

• Clearance：At least 250 mm from structural soffit to finished face (hangers and runners take 60–80 mm)

• Wall condition：Correct flatness deviations over 5 mm first, otherwise the wall angle cannot seat and the gap will not close

• Environment：Room temperature ≥5 °C, RH ≤80 %, openings closed, no through draught

2.2 Tools and equipment

2.3 Parts list and reference quantities

Estimated for 600×600 tiles with main runners at 1200 mm; includes normal wastage. Wall angle is counted per perimeter.

2.4 Delivery and site conditioning

• Store runners indoors and flat on bearers at ≤1.5 m centres, stacked no higher than 1.2 m so self-weight cannot bow them

• Never store outdoors or leaning against a wall — long runners take a permanent set

• Keep one manufacturer and one series per ceiling area; flange height and slot dimensions differ between brands

• Touch up damaged paint and seal every cut end, or corrosion starts exactly there

03Component Identification

Figure 1 Main components of the grid system ① main runner ② cross tee ③ wall angle ④ hanger clip ⑤ splice piece ⑥ expansion bolt and hanger rod.

Table 2-1 Function of each component

04Installation Sequence

1. Set out - Snap the finished ceiling level line (closing on all four walls), the main runner lines and the hanger positions. Level deviation ≤3 mm.

2. Fix the wall angle - Keep the lower edge of the L angle flush with the level line, fix with powder-actuated pins or M6 plugs at ≤300, miter corners at 45°. Level uneven walls first.

3. Install hanger rods - M8 expansion bolt plus φ6 rod. Drill 10 mm deeper than the anchor length, clean the hole, drive the anchor and tighten until the washer is flat. Rods plumb, without joints, ≤300 from the end of the main runner.

4. Install main runners - Keep all hanger hooks facing the same way; extend runners with splice pieces inserted symmetrically on both sides, pushed fully home until the dimples pop out. Apply camber of 1/200–1/300 of the short span.

5. Install cross tees - Square to the main runners; insert the end tab vertically into the hole until it locks with a light click; rest the wall end on the wall angle flange without fixing it (a little slip must be allowed).

6. Level - Run lines in both directions and adjust each hanger nut; flatness ≤3 mm/2 m, height difference between adjacent runners ≤1 mm. When finished, retighten all nuts.

7. Touch up - Apply two coats of anti-rust primer or matching paint to every cut, drilled hole and scratch.

8. Concealed works inspection - Check hanger spacing, staggered joints, locked tabs, camber and back-bracing; sign off before the tiles go up.

How to set the camberCamber is not simply raising the middle: it must form an even curve. Leave the end hangers untouched and raise the hanger nuts progressively from each end toward the center, so that the mid-point lift equals the short span × (1/200 to 1/300). Example: a 6 m span needs 20–30 mm of camber. After raising, check the curve against a taut line; a kink means one hanger has been adjusted too far.

05Connection Details

5.1 Anchoring the Hanger Rod

• Concrete slab: drill with a rotary hammer, clean the hole, fit an M8 expansion bolt and tighten until the washer is flat;

• Never fix into hollow brick, aerated block, render or the ceiling board itself;

• On prestressed slabs or where services are congested, use chemical anchors or add a transfer beam (angle or channel);

• Rods longer than 1.5 m need back-bracing (diagonal angle) to stop sway;

• Chip the slag from welded connections and touch up with anti-rust paint.

5.2 Extending a Main Runner

• Insert the splice symmetrically on both sides, push it fully home and let the locating dimple pop out;

• Joints in adjacent runners must not sit in the same vertical plane; stagger them by at least one hanger spacing;

• Keep the joint at least 300 from a hanger; after extending, push and pull sideways to check for looseness or a step.

5.3 Cross Tees and Wall Angle

• The cross tee tab must go in vertically; entering at an angle damages the hole and will not lock;

• Install each row of cross tees to a taut line; reject bent or twisted pieces;

• Miter wall angle corners at 45° and check internal and external corners for square;

• When fixing the wall angle to a lightweight partition, the fixings must land on the studs or on embedded supports.

06Quality Requirements

Table 5-1 Installation control values

07Common Errors and Consequences

Table 6-1 Wrong practice

08Product Storage and Handling

Figure 2 Grid stacking Store flat, banded into bundles, stack height ≤1.5 m; stored upright or leaning, long runners take a permanent bend and the joints run out of line once installed.

8.1 Environment

Table 7-1 Warehouse conditions

8.2 Handling

• Carry long runners with several people and limit mid-span sag (sag beyond 50 mm causes plastic deformation);

• Never throw, drag or stand on the runners;

• Cut on a flat surface and touch up the cut at once;

• Temporary site storage also needs dunnage; never lean runners against a wall.

8.3 Transport

• Load flat with dunnage at ≤1.5 m spacing and lash the load down;

• Cover with a rain-proof tarpaulin to keep rain from causing white rust;

• Never crush under heavy goods or stack other materials on the runners;

• Use slings for loading; never lift with wire rope directly (it crushes the flange).

09Appendix: Delivery Inspection

• □Size and wall thickness match the order (sample the strip thickness with a caliper)

• □Zinc coating even, no white rust, no exposed steel

• □Paint even, no runs, no flaking

• □Section straight, no twist or kink (bow ≤2 mm per 1 m)

• □Holes and tabs intact, splice pieces matched

• □One batch, with the factory inspection report

10Frequently asked questions

Can I use a painted grid under an outdoor canopy?

No. The paint film is only 20–30 μm and chalks under UV and rain, while cut ends rust first. Use aluminum framing or stainless accessories outdoors.

Can hangers go at 1500 mm to save rods?

No. Deflection of an exposed grid follows hanger spacing; beyond 1200 mm the joints go wavy first and extra camber will not compensate.

Painted grid or plain galvanized — which is better?

Use painted where the grid stays visible, because the film controls appearance. Use plain galvanized in concealed locations with a heavier zinc coating. Never mix both in one visible ceiling.

Can main runners be cut on site?

Yes, but prime both cut ends with two coats and re-plan hangers so each cut end has one within 300 mm. A cut runner cannot be used as a wall angle.

Why do the joints rust first?

A splice shears the coating and the clip rubs zinc off, exposing bare steel. Check that each splice is fully engaged and touch up 50 mm either side.

How soon can tiles be laid?

As soon as the grid is leveled and checked — usually the same day. Finish duct insulation and sprinkler testing first so tiles do not come out and break tabs.

About Pandaboard

Guangzhou Panda Commercial Development Co., Ltd. · Pandaboard / PEIDA

We manufacture and export gypsum board, mineral fiber and fiberglass ceiling tiles, calcium silicate and magnesium oxide boards, fiber cement board, aluminum ceilings, WPC and SPC wall panels, exterior decking, fencing and handrails, together with the matching grid and framing systems. The methods on this page are compiled from product behaviour and standard trade practice; for any project, follow the approved drawings, local codes and the specification confirmed on your order.

Website: www.pandamanufacturer.com Contact sales: contactus

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Guangzhou Panda Commercial Development Co., Ltd. · Pandaboard / PEIDA
This guide is technical information for specifiers and installers; it does not replace project drawings or local codes.