Description
Two slabs to a pack and 1.2 m² of wall per pack: the 160 mm ROCKWOOL FRONTROCK SUPER is the deepest of the four dual-density boards Renders World lists in the mineral wool insulation range, and every figure below is quoted from the declaration, product card and datasheets fetched for this revision.
Where 160 mm of Stone Wool Goes on a UK Wall
The Rockwool Super 160mm mineral slab declares a thermal resistance of 4.40 m²K/W and reaction to fire Euroclass A1 under EN 13501-1, which puts it on deep-retrofit elevations where a non-combustible layer has to carry the render.
Depth at this end of the range is bought for the layers it removes as much as the resistance it adds: one board reaches 4.40 m²K/W where the 120 mm slab declares 3.30 m²K/W, a difference of 1.10 m²K/W per board, and the boarding sequence stays single-layer.
- Solid-wall retrofit: uneven pre-1919 brick worked as a whole elevation, in the sequence the Victorian solid-wall retrofit guide sets out.
- Elevations specified as non-combustible: the A1 class is declared for the slab itself, and the 2026 facade fire requirements briefing covers where that becomes the specification driver.
- 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.
- Deep upgrades on masonry: declared for external thermal insulation composite systems on masonry, monolithic and precast external walls.
What the Extra Depth Buys Over a Thinner Super Slab
The case for the deepest board in the range is part thermal and part mechanical, and separating the two makes the specification easier to defend at handover.
- Declared resistance in one board: 4.40 m²K/W at 160 mm against 3.30 m²K/W at 120 mm, so the deeper target is met without a second layer and its staggered-joint setting out.
- Non-combustible at material level: Euroclass A1 for the product, declared durable against heat, weathering and ageing in the same document.
- A face that takes the base coat: compressive stress of 20 kPa at 10% deformation overall, with the manufacturer's product card putting the top layer at 40 kPa — the firm outer surface ROCKWOOL credits with preventing overdriven fixings.
- Bond strength across the slab: tensile strength perpendicular to the faces of 10 kPa, declared rather than quoted from a brochure.
- 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 stays a manageable condition.
- Stability at the joints: DS(70,-) and DS(70,90) at 1% or less, meaning the slab is not the source of movement where boards meet.
Declared Figures at 160 mm — Resistance, Fire and Strength
Each value below belongs to the slab as manufactured under EN 13162:2012+A1:2015 and declared by ROCKWOOL Polska at Cigacice under RW-CEE-DoP-0237/BCM/23/w1, notified body 1023.
| Property | Declared value | Test standard |
|---|---|---|
| Thermal conductivity (λD) | 0.036 W/mK | EN 12667 |
| Thermal resistance at 160 mm | 4.40 m²K/W | Declaration Table 2 |
| Reaction to fire | Euroclass A1 | EN 13501-1 |
| Compressive stress at 10% deformation | 20 kPa | EN 826 |
| Compressive stress, top layer | 40 kPa (product card) | 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), 1% or less | EN 1604 |
| Thickness tolerance | T5 | EN 823 |
Dividing 0.160 m by λ 0.036 W/mK returns 4.44 m²K/W and that arithmetic figure circulates widely, including in the previous version of this page. The declared row reads 4.40 — quote the declared value in anything a building control officer will read.
Two figures have come off this page for want of a source: the layer densities, which neither the declaration nor the product card states, and a specific heat capacity that had no document behind it. Point load has come off for a better reason — the 2023 declaration records it as no performance determined while the 07/2020 product card shows PL(5) ≥ 250 N, so treat point-load capacity as undeclared and design fixings to the system holder's figures.
A U-value belongs to the whole build-up rather than to a board, which is why none is published here; the U-value calculation guide shows how a declared resistance goes into that sum. The A1 class works the same way: it is declared for the slab and its declaration number, and a wall finished in an organic render is assessed as an assembly on its own evidence.
Pack, Pallet and Price at 160 mm
Ordering the Rockwool Super 160mm mineral slab is a pallet conversation rather than a pack one, because pack coverage steps down at this thickness while slab dimensions stay the same.
| Ordering detail | Figure |
|---|---|
| Slab dimensions | 1000 × 600 mm |
| Slabs per pack / pack coverage | 2 / 1.20 m² |
| Packs per pallet / pallet coverage | 12 / 14.40 m² |
| Pallet footprint and maximum height | 2000 × 1200 × 1330 mm |
| Listed pack weight | 16.5 kg |
| Listed price | £45.40 per pack, August 2026 |
At 1.2 m² per pack that works out at £45.40 ÷ 1.2 m² = £37.83 per m² for the board alone, August 2026, with adhesive, mesh, fixings and render costed separately. The slab was listed as available at the same fetch, and ROCKWOOL supplies this product on pallets only.
Renders World processes orders the same day where stock is available, and pallets ship next working day by courier or in two business days on the economy option, delivered kerbside. Orders over £300 travel free by company van within 15 miles of the Southampton base, then £1.50 per additional mile up to 60 miles.
How to Install the 160 mm Slab Under Render
Stone wool takes a cementitious adhesive because the open fibre structure gives polyurethane foam nothing to key into, so the bonding product is chosen before anything reaches the scaffold.
- Bond with the wool-compatible adhesive: Roker U grey adhesive serves as both bonding coat and reinforcement base coat, and it is not interchangeable with the polystyrene-only products.
- Trial the substrate first: ROCKWOOL recommends pre-installation trials to confirm that the unevenness in the wall can be covered without gaps opening between slabs — cheap insurance before 14.40 m² of pallet lands.
- Dense face outward: the top layer is branded "THIS SIDE UP" precisely so the hardened surface, the one that takes the base coat and the fixing plates, is identified in seconds.
- Butt the joints tight: ROCKWOOL's EWI datasheet notes that the fibres of adjacent slabs knit together when tightly butt jointed, which is what closes the gaps a thermal image would otherwise find.
- Take fixings from the specification: plug length, plate diameter and count per m² come from the system holder and a project wind-load calculation rather than from a rule of thumb, and the hardware is then selected from the insulation fixing accessories range. The fixing pattern and spacing guide covers how that layout is set out.
- Reinforce and finish: mesh and base coat follow with the cementitious products in the EPS adhesives basecoats range, then a vapour-open render keeps the build-up consistent with the board beneath it.
One set-out point is worth checking against any ROCKWOOL literature already in the project file: this slab measures 1000 × 600 mm, while the UK External Wall Dual Density Slab datasheet describes a 1200 × 600 mm board. Set out to 1000 mm and the courses land where the drawing says they will. Store packs indoors or under waterproof covering, as that datasheet asks, and dry packs board faster.
How 160 mm Compares With the Thinner Super Boards
| Slab | Declared resistance | Pack |
|---|---|---|
| FRONTROCK SUPER 80 mm | 2.20 m²K/W | 3 slabs, 1.80 m² |
| FRONTROCK SUPER 100 mm | 2.75 m²K/W | 3 slabs, 1.80 m² |
| FRONTROCK SUPER 120 mm | 3.30 m²K/W | 3 slabs, 1.80 m² |
| FRONTROCK SUPER 160 mm | 4.40 m²K/W | 2 slabs, 1.20 m² |
All four share the same declared λ, fire class and strength classes, so thickness and pack format are the whole of the difference. The pack change at 160 mm is the one that surprises buyers: coverage drops by a third per pack, which is a delivery and scaffold-loading question rather than a performance one.
Choosing Between 160 mm and a Thinner Slab
- Specify 160 mm when the calculation asks for it: 4.40 m²K/W in a single board is the deepest resistance on this shelf, and single-layer boarding keeps the sequence simple at that depth.
- Step down where the target allows: the 120 mm Super slab declares 3.30 m²K/W with 1.80 m² per pack, which is lighter on cost, handling and pallet count.
- Check reveals and sills before ordering: a 160 mm build-up changes reveal geometry and base-track depth, so confirm both at survey and order the profiles with the slabs.
- Weigh the material choice openly: the mineral wool against polystyrene comparison sets out where a non-combustible board is worth its cost per millimetre and where it is not.
Where the answer is 160 mm, Renders World holds the slabs by the pallet and the wool-compatible adhesive alongside them, so a full elevation can be ordered in one call.
FAQ — Ordering, Fixing and Fire at 160 mm
How many packs does a 100 m² elevation take?
100 m² ÷ 1.20 m² per pack = 83.4, rounded up to 84 packs; adding 5% for cuts at reveals and returns gives 105 m² ÷ 1.20 = 87.5, so 88 packs. At 12 packs to a pallet that is 7.3 pallets, which is worth staging against scaffold-loading capacity rather than landing in one drop.
What bonds and fixes a 160 mm stone wool slab?
Cementitious adhesive on a full bed to the dense face, then mechanical fixings whose length and count come from the system holder's specification and a project wind-load calculation. No plug-to-thickness table is published here, because that mapping belongs to the fixing manufacturer rather than to arithmetic.
Is 160 mm worth the step up from 120 mm?
The gain is 1.10 m²K/W of declared resistance per board, against a third less coverage per pack and a proportionate rise in pallet count and material cost. Where the wall calculation is satisfied at 3.30 m²K/W, the thinner board is the better buy; where it is not, one deep board beats two stacked layers.
Does the A1 class cover the finished wall?
Euroclass A1 under EN 13501-1 is declared for the slab under RW-CEE-DoP-0237/BCM/23/w1, and it is the material-level fact a designer starts from. The completed external wall, render included, is assessed as an assembly on its own evidence under current Approved Document B guidance.
When does a specification become two layers?
ROCKWOOL's EWI datasheet reserves double layering for insulation thicknesses greater than 250 mm, installed in a brick bond pattern with the thinner board first. Below that, a single slab such as this one keeps the interlayer detailing out of the programme altogether.
Technical Documentation — FRONTROCK SUPER Declaration and Datasheets