Technical guide · Pandaboard

Rock Wool Ceiling Tile: Hanger Checks, Installation and Storage

Rock wool ceiling tiles are molded from basalt wool and binder, typically 600×600 mm and 15–25 mm thick at 300–500 kg/m³, giving 5–9 kg/m² — 1.5 to 2 times the weight of mineral fiber tiles of the same thickness. They still use T24×38 main runners at ≤1200 mm, T24×26 cross tees at 600 mm and an L wall angle, but hanger spacing must be checked against tile plus grid weight rather than copied from a mineral fiber layout. They are Class A1 non-combustible and stable to about 90% RH, and cutting generates heavy dust that needs extraction.

Rock wool ceiling tiles are made from natural rock (basalt, diabase) melted and fiberized, then bonded and pressed. They are a Class A1 non-combustible material with a melting point above 1000 ℃, and also offer good sound absorption and moisture resistance. The difficulty is not the workmanship but self-weight and dust: tiles weigh twice as much as mineral fiber and produce heavy cutting dust.

01Key specifications and suitability

Suitable

• Escape routes and lobbies needing Class A1

• Corridors outside plant rooms

• Theaters and music rooms

• Hospital and school corridors

• Damp but not wetted basements

Not suitable

• Pools, showers and wash-down areas

• Outdoor and semi-outdoor canopies

• Chemical plants with acid or alkali mist

• Thin steel decks where hangers cannot be added

• Kitchen lines that are scrubbed down

02Preparation Before Installation

2.1 Load check

Rock wool tiles weigh about twice as much as mineral fiber, so verify the following before installation:

• Hanger spacing: normally still 1200×1200, but hanger rods must be φ6 full-thread with no joints;

• Load per point = tile weight + grid weight; check expansion bolts with a safety factor of 1.5;

• For large areas or high spaces (clear height >6 m), tighten hangers to 1000×1000;

• Provide independent hangers for light fittings and air diffusers; never hang them from the main runner.

2.2 Site conditions

• Services above the ceiling complete and accepted, no leakage;

• Ambient temperature ≥5 ℃, relative humidity ≤80 %;

• Tiles delivered 24 h in advance, stored flat in the original packaging;

• Confirm that the grid load capacity matches the tile weight.

2.3 Tools and protection

Laser level, rotary hammer, fine-tooth saw (with dust extraction), utility knife, leveling wrench, 2 m straightedge; PPE: KN95 mask, goggles, long sleeves, cut-resistant gloves. Rock wool fibers are coarser than glass fiber, but the dust volume is greater.

2.4 Parts list and reference quantities

Estimated for 600×600 tiles with main runners at 1200 mm and cross tees at 600 mm; includes normal wastage.

2.5 Delivery and site conditioning

• Move boards indoors at least 24 h before installation and stack them flat on bearers at ≤600 mm centres so moisture content equalises with the room and shrinkage joints do not open later

• Use one batch and one shade per room or elevation; mixing batches shows as a visible colour difference

• Spot-check 5 % on arrival: flat face, intact edges, no blistering or scratches; reject boards with diagonal deviation over 2 mm

• Cut in a separate area, clear dust immediately and seal cut edges as described in this guide

03Method 1: Exposed Grid

Figure 1 Exposed grid layout Rock wool tiles are heavy: main runner spacing must not exceed 1200 and joints must be staggered.

1. Snap lines - Close the level line loop on all four walls and snap the main runner and hanger positions at the same time.

2. Fix the wall angle - L wall angle at ≤300 spacing, 45° at corners, walls leveled first.

3. Install hanger rods - M8 expansion bolt + φ6 full-thread rod, vertical with no joints, ≤300 from the end of the main runner; tighten to 1000×1000 where the clear height is >6 m.

4. Install main runners - Camber 1/200–1/300, joints staggered by at least one hanger spacing, retighten all hanger clips.

5. Install cross tees - Spacing 600, tabs pushed fully home; rock wool tiles are heavy, and an unlocked tab drops the tile.

6. Leveling - Flatness ≤3 mm/2 m, joint lippage ≤1 mm.

7. Lay tiles - Support the edges with both hands and tilt the tile into place; never grab one corner — rock wool corners are stronger than mineral fiber, but knocks still break pieces off.

8. Cutting - Cut with a fine-tooth saw and dust extraction; seal the cut with matching edge paint or aluminum foil tape.

04Method 2: Concealed Grid

• Use tongue-and-groove rock wool tiles with the dedicated concealed grid;

• Level the concealed grid to ≤1 mm; tile weight magnifies any unevenness;

• Install with suction cups or a tile lifter, pushing tiles in one by one;

• Leave a 2 mm joint and do not fill it with compound;

• Provide an access panel every 50 m², with independent hangers for the frame.

05Junctions and Details

Figure 2 Tile bearing on the grid Because the tiles are heavy, all four edges must bear fully on the flange; any unsupported edge will sag over time.

• Light fittings and air diffusers: independent hangers, with an aluminum angle frame around the opening;

• Access panels: at least 2 independent hangers for the frame, with a safety chain on the cover;

• Fire stopping: seal around pipes penetrating the slab to fire requirements; never substitute rock wool tile offcuts;

• Wall junction: leave a 5–8 mm gap and close it with a matching trim.

06Quality Acceptance

Table 6-1 Permissible deviations

07Common Problems

Table 7-1 Typical defects

08Product Storage and Handling

Figure 3 Stacking Rock wool tiles are heavy: limit the stack height to ≤1.0 m so the bottom layer is not crushed out of shape.

Table 8-1 Storage conditions

Handling: two people lift by the edges; use a flat trolley for long moves; never drag or throw. Recommended stock age ≤6 months; for older stock, sample-check density and face flatness.

09Transport and Safety

• Load flat, stack height ≤1.0 m, strapped down and covered with a waterproof tarpaulin;

• Do not compress under heavy goods; pass tiles one by one when loading and unloading;

• Cutting requires dust extraction, a KN95 mask and goggles;

• Rock wool dust irritates the airways; no eating or drinking in the work area;

• Wear a harness for work at height; never stand on the tiles.

10Appendix: Checklists

10.1 Goods receiving

• □Size, thickness and density match the order

• □Face flat, no chipped corners, no stains

• □Packaging intact, no damp weight gain

• □Class A1 fire performance report supplied with the goods

• □Same batch number

10.2 Before installation

• □Load check completed, hanger spacing compliant

• □Hanger rods φ6 full-thread, no joints

• □Grid tabs intact

• □Dust extraction and PPE on site

• □Cutting area isolated

11Frequently asked questions

Rock wool or mineral fiber tile — which one?

Choose rock wool where Class A1 non-combustibility, higher absorption or better humidity resistance is required, but check hangers and grid for the extra weight. Mineral fiber is more economical for ordinary office ceilings.

Can rock wool tiles be used in wet areas?

They work to about 90% RH, better than the 70% limit for mineral fiber, but they are still unsuitable for pools and kitchens with free water or wash-down. Use clip-in aluminum or calcium silicate board there.

Why check hangers for tile weight?

At the same 1200×1200 layout a rock wool ceiling carries about twice the load of a mineral fiber ceiling, so anchors in masonry or thin slabs may be inadequate. If the check fails, tighten hangers to 1000×1000 mm.

How do I control cutting dust?

Cut behind a screen or outdoors with a mobile extractor or wet collection, and wear a P2 mask. Do not cut tiles in a finished area; settled dust is difficult to remove from ceilings and furnishings.

Can one person install these tiles?

Not recommended. A 20 mm tile weighs about 2–3 kg but is large and brittle at the edges, so two people should lower it together. Work from a platform rather than receiving tiles on a ladder.

Do rock wool tiles work on a concealed grid?

Yes, with tegular edges and concealed-grid clips. Because the tile is heavier, keep the clip spacing specified by the system supplier and do not omit or widen it.

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.