Description
This Rockwool 120mm slab is FRONTROCK SUPER from ROCKWOOL, a dual-density stone wool board for insulating external walls under render. At 120 mm it declares 3.30 m²K/W, and a pack of three 1000 × 600 mm slabs covers 1.8 m². It is one of four Super thicknesses in the Renders World mineral wool insulation range.
Where a Rockwool 120mm Slab Fits
Choose 120 mm when the wall calculation needs more than the 100 mm slab gives and the sills, roof edges and boundary still leave room for the extra 20 mm.
- Main elevations of masonry or concrete finished with a thin render system.
- Older solid walls, where the open structure helps the masonry dry outwards; see the solid-wall retrofit guide.
- Facades that take knocks, thanks to the harder top layer.
Why Choose Frontrock Super at 120 mm
- 3.30 m²K/W declared at this thickness, against 2.75 for the 100 mm slab.
- Harder outer layer — ROCKWOOL gives about 40 kPa compressibility for the top layer of the two-density build.
- A1 slab, declared by ROCKWOOL.
- MU1 vapour class and water absorption declared at no more than 1.0 kg/m² short term and 3.0 kg/m² long term.
- CS(10)20 and TR10, the same declared strength classes as every Frontrock slab sold here.
Frontrock Super 120 mm Specification
| Property | Declared value |
|---|---|
| Product | ROCKWOOL FRONTROCK SUPER, 120 mm |
| Slab build | Stone wool, dual density, harder top layer |
| Slab size | 1000 × 600 × 120 mm |
| Declared thermal conductivity λD | 0.036 W/mK |
| Declared thermal resistance RD | 3.30 m²K/W |
| Reaction to fire (the slab) | Euroclass A1 |
| Compressive strength at 10 % deformation | CS(10)20 — 20 kPa |
| Tensile strength perpendicular to faces | TR10 — 10 kPa |
| Short-term water absorption | WS — up to 1.0 kg/m² |
| Long-term water absorption | WL(P) — up to 3.0 kg/m² |
| Water vapour diffusion resistance | MU1 |
| Dimensional stability | DS(70,−) and DS(70,90) |
| Thickness tolerance | T5 |
| Pack | 3 slabs, 1.8 m² |
| Maker's pallet | 12 packs, 21.6 m² |
| Standard and declaration | EN 13162:2012+A1:2015 · DoP RW-CEE-DoP-0237/BCM/23/w1 |
Declared in DoP RW-CEE-DoP-0237/BCM/23/w1 (ROCKWOOL Polska, Cigacice, EN 13162, notified body 1023). Put the declared 3.30 m²K/W into the U-value calculation guide together with the other layers.
Installing the 120 mm Slab
Roker U grey adhesive bonds mineral wool facade slabs up to 30 cm thick and forms the mesh layer. Its data sheet sets the steps:
- Skim the face, then comb on the bonding coat with a 10 × 10 mm notched trowel, at about 4.5–5.5 kg/m².
- Push the slab into place, tap it level and offset the vertical joints.
- Anchor no sooner than the next day, using galvanised metal-pin anchors, four per m² as a minimum or more where the design asks.
- Three days after bonding, embed the mesh between two passes of mortar.
All Frontrock Thicknesses
| Slab | Density | Declared RD | Pack |
|---|---|---|---|
| Frontrock Plus 50 mm | single | 1.40 m²K/W | 6 slabs · 3.6 m² |
| Frontrock Plus 80 mm | single | 2.25 m²K/W | 5 slabs · 3.0 m² |
| Frontrock Super 80 mm | dual | 2.20 m²K/W | 3 slabs · 1.8 m² |
| Frontrock Super 100 mm | dual | 2.75 m²K/W | 3 slabs · 1.8 m² |
| Frontrock Super 120 mm (this slab) | dual | 3.30 m²K/W | 3 slabs · 1.8 m² |
| Frontrock Super 160 mm | dual | 4.40 m²K/W | 2 slabs · 1.2 m² |
The 100 and 120 mm Super slabs come in identical packs, so moving up to 120 mm changes nothing in how the packs are handled on site. Frontrock Plus, the single-density line, covers 50 and 80 mm.
Ordering and Pallets
Divide the wall area by 1.8 m² and round up, allowing for cuts at openings. ROCKWOOL palletises 120 mm at 12 packs, 21.6 m², to a pallet. Order the Roker U adhesive with the slabs.
Is 120 mm Right for Your Wall?
- Yes where the calculation needs about 3.30 m²K/W, which the Rockwool 120mm slab declares.
- Drop to the Super 100 mm if the extra 20 mm will not clear the sills.
- Go to the Super 160 mm when the target asks for 4.40 m²K/W.
FAQ — Frontrock Super 120 mm
How much does one pack cover?
1.8 m² — three slabs of 1000 × 600 mm.
Which adhesive should I order?
Roker U grey, which bonds mineral wool facade slabs and carries the reinforced layer.
What anchors does the slab need?
Roker U’s data sheet asks for anchors with a galvanised metal pin, at least four per m², set the day after bonding at the earliest; the guide to installing insulation fixings covers the work.
Is it A1?
The slab is declared Euroclass A1. The finished rendered wall is classified as a complete system.
What is the R-value at 120 mm?
Declared thermal resistance 3.30 m²K/W; declared conductivity 0.036 W/mK.
Will it cut outside noise?
ROCKWOOL lists acoustic insulation among the slab’s features. For a sound target, rely on a tested result for the whole wall.
Technical Documents — Frontrock Super