A module leaves the factory on a truck, gets craned onto a foundation, and is weathertight the same afternoon. That schedule is the whole point of offsite construction. It also breaks most of the assumptions baked into a traditional cladding spec.
Natural stone is too heavy to travel on a finished wall. Rigid tile cracks when the frame twists on the road. Render needs days on site, in weather nobody controls. MCM flexible stone sits in the gap: real mineral texture, 2–9 mm thick, 3.0–10.5 kg/m². Heavy enough to read as stone. Light enough to survive the journey.
Offsite Changes What “Cladding” Has To Do
A site-applied facade only has to stay put. A factory-finished module has to stay put while moving. Different problem.
Three things shift. Weight, because transport limits are measured per module and per axle, not per square metre of wall. Bond behaviour, because the panel is bonded horizontally in a shop and then stood upright, flexed, and vibrated. And repair access — a panel fitted in the factory can be inspected under good light, which is worth more than it sounds.
We have seen modules arrive with a stone-look finish that debonded along one edge. The cause was never the material. It was a substrate that had not been sealed, or a bond applied at 8 °C in an unheated shed in February.
Where The Panel Sits In A Modular Wall Build-Up
MCM is a finish layer, not a structural one. It goes onto a board, not onto studs. Get the board right and everything downstream is straightforward; get it wrong and no adhesive will save you. See our technical specifications sheet for the full property table.
| Substrate | Works? | What to do first |
|---|---|---|
| Fibre cement board | Yes — the default | Dust off, prime if porous |
| MgO board | Yes | Check for surface chalking; seal it |
| Exterior-grade plywood | Yes, indoors or protected | Fill the face veneer checks |
| OSB | Yes, with a skim | Skim or it telegraphs through thin sheets |
| Galvanised steel sheet | Yes | Abrade and degrease; no mechanical key otherwise |
| Existing ceramic tile | Yes — the retrofit case | Fill deep grout lines before bonding |
| Bare insulation board | No | Needs a structural skin over it |
That last row matters. Insulation is not a substrate. Neither is foil facing. If a module design hands you EPS or mineral wool as the outer face, something upstream is missing.
Bond It In The Factory, Not On Site
This is the single biggest advantage, and the least appreciated.
In a shop you control temperature, dust and handling time. You can lay sheets flat and roll them rather than fighting gravity on a scaffold. Cure happens at 10–32 °C instead of whatever the site offers. Our step-by-step installation guide walks through the sequence; in factory conditions you can compress the waiting, not skip it.
Use a polymer-modified adhesive, C2 class. Not a mastic. Mastics stay soft, and a soft bond line plus road vibration plus thermal cycling is how you get creep on a vertical surface. Details in the adhesive guide.
One thing to plan for: modules are usually finished lying down and shipped standing up. Bond the panel in the orientation it will live in, or accept a full cure before the module is rotated.
The Weight Arithmetic
Weight is not a spec-sheet curiosity here. It decides how many modules fit per load, whether you need a bigger crane, and whether the frame needs redesigning.
| Cladding | Typical weight | Consequence for a module |
|---|---|---|
| MCM flexible stone | 3.0–10.5 kg/m² | No frame change; no crane upgrade |
| Ceramic or porcelain tile | 15–25 kg/m² | Heavier frame, more fixings |
| Thin natural stone veneer | 25–40 kg/m² | Structural review in most cases |
| Full stone cladding | 40–80 kg/m² | Offsite becomes uneconomic |
Subtract 20 kg/m² from a 40 m² wall and you have removed roughly 800 kg. That is the difference between two modules per truck and three. Freight maths, not aesthetics — though it usually lands on the same answer.
Fire Behaviour In A Finished Module
TooFlexi MCM flexible stone is A2 class (GB 8624, factory tested). Limited combustibility, not non-combustible — the distinction gets specified wrong often enough that it is worth stating plainly.
Why it matters for modular: a factory-finished module arrives with its finishes already enclosed. Inspectors cannot open up the wall to check what is behind the cladding. So the declared classification of the finish layer carries more weight than it would on a site-built facade. More background in our A2 class (GB 8624) and compliance guide and the broader fire safety guide.
Thickness, Sheet Size, Panel Layout
Thickness runs 2–9 mm. Most architectural patterns sit in the lower half of that range; heavier relief textures go thicker. Standard sheets are 600 × 1200 mm and 1200 × 2400 mm, with 1200 × 3000 mm and 1200 × 3200 mm available by series. Mushroom stone textures are the exception — those run 6–15 mm.
Layout discipline pays off. Set out from the module corner, not from the sheet edge, or your joints will creep out of alignment across a run of units. Larger sheets mean fewer joints, but they are harder to handle in a confined shop and less forgiving on a substrate that is not perfectly flat.
Curved corners and column casings are viable — the material bends to a radius of roughly 200 mm at standard thicknesses. See the curved walls and columns guide for the limits.
What Actually Fails In Transit
Not the cladding. Almost never the cladding. The failures we get called about are these:
- Joints closed up tight. Modules flex. Leave 2–3 mm movement joints at panel edges and fill them with a flexible sealant, not rigid grout.
- Adhesive skinned over. If the trowel ridge sits too long before the sheet goes on, the bond is a fraction of what the datasheet promises.
- Notched trowel too shallow. On a substrate with any relief, a 4 mm notch leaves voids. Voids become visible as the sheet settles.
- Edges unprotected. Corners take the knocks in transit. Arris the substrate or use a trim; a sharp 90° corner will crack a wrap.
- Condensation trapped in shrink wrap. Wrap a finished module for weeks and you have built a greenhouse. Vent it.
Outdoor durability after delivery is a separate question, covered in the weather resistance guide.
Specifier Checklist
- Name the substrate explicitly. “Suitable board” is not a substrate.
- Specify C2 polymer-modified adhesive and the trowel notch depth.
- Fix the movement joint width in the drawing, not in a note.
- Declare the fire classification you need and the standard it is tested against.
- Decide in writing whether panels are applied before or after module rotation.
- Set the texture family and sheet size before ordering — both vary by series.
- Plan logistics early; we ship FOB from ports in Guangdong and Guangxi, and minimum order quantity starts at 200 m² per colour. Our shipping and logistics guide covers the paperwork.
Frequently Asked Questions
Can MCM flexible stone be applied to a module before it leaves the factory?
Yes, and it is the better sequence. Factory conditions give you controlled temperature, flat working surfaces and inspection under proper light. Bond the sheets in the orientation the wall will finally sit in, or let the adhesive cure fully before the module is rotated upright.
How much does the cladding add to a module’s weight?
Between 3.0 and 10.5 kg/m² depending on texture, plus the adhesive bed. On a 40 m² wall that is roughly 120–420 kg of finish — far below the 600–1,600 kg you would add with tile or thin stone, and low enough that most module frames need no redesign.
What is the fire classification?
A2 class (GB 8624, factory tested). A2 means limited combustibility, not non-combustible. If your project requires a European classification, say so at enquiry stage so the specification can be written to match.
Will the panels crack when the module flexes during transport?
Not if the joints are there. The material takes far more movement than a rigid tile, but a jointless run across a flexible frame will eventually show it. Leave 2–3 mm movement joints and fill them with flexible sealant.
Which substrates work on a modular wall?
Fibre cement board is the default and the safest choice. MgO board, exterior plywood, OSB with a skim coat, and degreased galvanised steel all work with the right preparation. Insulation board does not — it needs a structural skin over it.
What sheet sizes are available?
600 × 1200 mm and 1200 × 2400 mm as standard, with 1200 × 3000 mm and 1200 × 3200 mm available on selected series. Availability varies by texture, so confirm the size at the same time you confirm the pattern. The full library is in the texture catalog.
Is it suitable for exterior modules in cold climates?
Yes. Water absorption is low, the material handles freeze-thaw cycling, and the mineral pigments are UV-stable. Seal exterior joints and detail the edges so water cannot get behind the sheet.
