Description
Three slabs to a pack covering 1.8 m²: the 80 mm ROCKWOOL FRONTROCK SUPER is the dual-density board in our mineral wool insulation range, and it is bought for what it withstands rather than for what it saves on the U-value. Every figure below is quoted from the FRONTROCK SUPER Declaration of Performance and ROCKWOOL's published parameter table for this product, both fetched for this revision.
Where the Dual-Density Stone Wool Slab Earns Its Place
The Rockwool Super 80mm mineral slab declares a thermal resistance of 2.20 m²K/W under EN 13162 and reaction to fire Euroclass A1, which puts it on elevations where a non-combustible layer has to survive handling and impact as well as insulate. ROCKWOOL describes the board itself as a dual-density non-combustible stone wool slab that protects an ETICS facade against mechanical damage both in service and during installation — that description, not a thermal figure, is the reason it sits above the single-density board in the range.
- Ground-floor and street-facing zones: the lower reaches of an elevation, where the render substrate takes knocks that a softer board would carry through to the finish.
- Solid-wall retrofit: uneven pre-1919 brick, worked as a whole elevation in the Victorian solid-wall retrofit sequence.
- Vapour-open build-ups: a declared water vapour diffusion resistance factor of 1 keeps the insulation layer about as open to outward drying as a solid material gets.
- Projects specifying non-combustible insulation: the A1 classification is declared for the slab, and the 2026 facade fire requirements briefing covers where that becomes a regulatory driver rather than a preference.
Why Specifiers Put the Super Slab on Exposed Walls
The case for this board is mechanical and regulatory rather than thermal, and being clear about that makes the specification easier to defend.
- Non-combustible at material level: Euroclass A1 under EN 13501-1, declared for the slab and confirmed as durable against heat, weathering and ageing in the same declaration.
- Declared strength classes: compressive stress of 20 kPa at 10% deformation and tensile strength perpendicular to the faces of 10 kPa, both from the declaration rather than from a brochure.
- Manufacturer-stated impact protection: the dual-density construction is described by ROCKWOOL as protecting the facade during installation as well as in use, which is where the board differs from the single-density alternative.
- Water behaviour that suits a rendered wall: short-term absorption of 1.0 kg/m² and long-term absorption of 3.0 kg/m², so an exposed run during the boarding window is a manageable condition.
- Dimensional stability: declared DS(70,90) — stable at 70 °C and 90% relative humidity — so the slab is not the source of movement at board junctions.
Declared Performance for the FRONTROCK SUPER Slab
Each value below belongs to the slab as manufactured under EN 13162:2012+A1:2015, declared by ROCKWOOL Polska at Cigacice under RW-CEE-DoP-0237/BCM/23/w1, with notified body 1023.
| Property | Declared value | Test standard |
|---|---|---|
| Thermal conductivity (λD) | 0.036 W/mK | EN 12667 |
| Thermal resistance at 80 mm | 2.20 m²K/W | Declaration Table 2 |
| Reaction to fire | Euroclass A1 | EN 13501-1 |
| Compressive stress at 10% deformation | 20 kPa | EN 826 |
| Tensile strength perpendicular to faces | 10 kPa | EN 1607 |
| Water vapour diffusion resistance factor | 1 | EN 12086 |
| Short-term water absorption | 1.0 kg/m² | EN 1609 |
| Long-term water absorption | 3.0 kg/m² | EN 12087 |
| Dimensional stability | DS(70,-) and DS(70,90) | EN 1604 |
| Thickness tolerance | T5 | EN 823 |
One reading of that table is worth carrying into a specification. Dividing 80 mm by λ 0.036 returns 2.22 m²K/W, and that figure circulates widely, but the declared row reads 2.20 — use the declared value in anything a building control officer will read. Two figures previously shown here have come off the page: the layer densities, which neither the declaration nor the manufacturer's parameter table states, and a specific heat capacity that has no source at all.
The A1 classification is declared for the slab, and it does not transfer to a wall finished in an organic render, which is assessed as an assembly on its own evidence under current Approved Document B guidance. Where the declared class matters to a project, quote it against the slab and its declaration number, which is the form a specifier can check.
Fitting the 80 mm Slab and What Goes With It
Stone wool takes a cementitious adhesive, because the open fibre structure gives polyurethane foam nothing to key into. Roker U grey adhesive is the wool-compatible product in the range and serves as both bonding coat and reinforcement base coat.
- Bond on a full bed: full contact across the back of the slab is what keeps the board solid under the impact loads this specification exists to handle.
- Orient the dense face outward: the hardened side takes the adhesive and base coat, so the branded face goes toward the render — a point of trade practice rather than a printed instruction.
- Butt the joints tight and stagger the courses: ROCKWOOL's EWI datasheet notes that fibres of adjacent slabs knit together when tightly butt jointed, and it calls for a brick bond pattern in its double-layer detailing to keep thermal bridging out.
- Take the fixing count from the specification: plug length, plate size and density come from the system holder and a project wind-load calculation, which is why no per-square-metre count is printed here — select the hardware from the insulation fixing accessories range once that figure is issued.
- Store under cover: the same datasheet asks for slabs indoors or under waterproof covering, and dry packs board faster.
Mesh and base coat follow with the cementitious products in the EPS adhesives basecoats collection, and a vapour-open finish keeps the diffusion path continuous to the surface. How that behaves across a full build-up is worked through in the condensation risk method for external insulation.
Super 80 mm Against the Thicker Slabs in the Range
All four Super thicknesses share one declaration, so they differ only in the declared resistance and in pack coverage.
| Slab | Declared R | Pack |
|---|---|---|
| Super 80 mm | 2.20 m²K/W | 3 slabs, 1.8 m² |
| Super at 100 mm | 2.75 m²K/W | 3 slabs, 1.8 m² |
| Super at 120 mm | 3.30 m²K/W | 3 slabs, 1.8 m² |
| Super at 160 mm | 4.40 m²K/W | 1.2 m² pack |
The comparison worth making is sideways rather than upward. At the same 80 mm, the Plus slab declares λ 0.035 W/mK and R 2.25 m²K/W against this board's 0.036 and 2.20, and both ranges declare identical 20 kPa compressive and 10 kPa tensile classes — so the Super name buys the dual-density construction and the protection ROCKWOOL attributes to it, not a better declared number. Specify it where the wall takes knocks, and take the thicker slabs where the calculation asks for depth.
Pack Coverage, Cost per Square Metre and Ordering
Each pack of the Rockwool Super 80mm mineral slab holds three slabs and covers 1.8 m², which is 0.6 m² of face area per slab (1.8 m² ÷ 3 = 0.6). The pack price on this page reads £39.00, August 2026, putting the insulation layer at £39.00 ÷ 1.8 m² = £21.67/m² in materials alone.
- Pack count: 100 m² ÷ 1.8 m² per pack = 55.6, rounded to 56 packs, +10% for cuts at reveals and returns = 62 packs.
- Adhesive and base coat: ordered against the same area, with consumption read from the adhesive's own sheet rather than from this page.
- Fixings: length matched to substrate plus 80 mm of board, count set by the specification.
- Finish: a vapour-open render, keeping the build-up consistent with the declared diffusion factor of 1.
Delivery at Renders World runs by courier or pallet, next working day on express and two days on economy, kerbside at the delivery address — a site-wide policy rather than a figure attached to this pack. Pack weight is not published here, because the store's weight field carries no value for this SKU and the previous figure rested on a density no document declares.
Is the Super 80 mm the Right Slab for the Elevation?
- Take this slab where a non-combustible layer at a declared 2.20 m²K/W has to sit on a wall that takes contact — ground-floor zones, access routes and public frontages.
- Go deeper in the same range where the calculation asks for it, starting with the 100 mm Super slab at a declared 2.75 m²K/W.
- Look at the Plus board for sheltered domestic elevations, where the declared thermal figures are marginally better and the pack covers more area; both sit in the same stone wool slab range.
- Weigh stone wool against polystyrene first if the fire strategy leaves the choice open, since the trade-off is classification and vapour openness against resistance per millimetre — the mineral wool and polystyrene comparison sets it out.
FAQ — Quantities, Fire Class and Compatibility at 80 mm
How many packs cover a 100 m² elevation?
Fifty-six packs cover the bare area, from 100 m² ÷ 1.8 m² per pack = 55.6, and 62 packs is the realistic order once 10% is added for cuts at reveals, returns and parapets. Ordering that allowance up front avoids a part-pack top-up mid-programme.
Does the Super slab outperform the Plus slab at 80 mm?
Not on declared thermal figures: this board declares λ 0.036 W/mK and R 2.20 m²K/W, against 0.035 W/mK and 2.25 m²K/W for the Plus slab at the same thickness, and both declare the same 20 kPa and 10 kPa strength classes. The difference ROCKWOOL states is the dual-density construction and the protection it gives the facade against mechanical damage.
Which adhesive suits dual-density stone wool?
A cementitious adhesive formulated for mineral wool fibres is the requirement, Roker U grey being the one stocked here, and it doubles as the reinforcement base coat. Foam adhesives are made for closed-cell boards and are not the route on a fibrous slab.
Can a U-value be quoted from this slab?
A U-value belongs to the whole build-up, so the declared 2.20 m²K/W is this layer's contribution and nothing more. Adding the layers up is covered in the U-value calculation method for wall insulation thickness.
What is worth checking when the pallet arrives?
Match the declaration travelling with the goods against RW-CEE-DoP-0237/BCM/23/w1, since ROCKWOOL declares from more than one plant and a slab produced elsewhere carries its own declaration. Confirming it at goods-in keeps the specification file clean.
Technical Documentation for the FRONTROCK SUPER Slab