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90mm Rockwool Flexi Acoustic Sound Insulation Slab (4.32m2/Pack)
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Flexible stone wool slab with an adaptable edge for friction fitting. Suitable for timber and metal frame walls, roofs, and floors. 90mm is ideal for delivering strong noise control in thicker framed walls.
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Thu 2 Oct
- 0days
- 17hrs
- 23mins
- 40secs
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Product Overview
Flexible stone wool slab with an adaptable edge for friction fitting. Suitable for timber and metal frame walls, roofs, and floors. 90mm is ideal for delivering strong noise control in thicker framed walls.
Delivery & Returns Information
How Our Delivery Works
We work with a nationwide network of trusted suppliers. As a result, items in your basket may be supplied by different suppliers and delivered separately. Where this applies, you'll see multiple delivery charges at checkout. We always aim to group products from the same supplier to keep delivery costs as low as possible.
Delivery Areas & Charges
Delivery charges listed on our website apply to mainland UK, excluding the following postcode areas: AB, CF, DD, DG, FK, KW, IV, LA, LD, LL, NP, PA, PH, SA, SY
If your delivery address falls within one of these postcode areas, we’ll be in touch before processing your order to confirm any additional delivery costs.
Please note: We do not currently offer delivery outside the UK mainland.
Standard (Nationwide) Delivery
| Insulation, Plasterboard and Drylining Products | |
|---|---|
| ORDER VALUE | DELIVERY CHARGE |
| Under £350 | £35 ex. VAT |
| Over £350 ex. VAT | FREE |
| Timber & Sheet, Building Materials, Joinery and Gardens & Landscaping Products | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £100 | £15 ex. VAT |
| Between £100 - £300 ex. VAT | £10 ex. VAT |
| Over £300 ex. VAT | FREE |
| Screws & Fixings and Adhesives & Sealants | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £50 | £5 ex. VAT |
| Over £50 ex. VAT | FREE |
Express Delivery
| Express Delivery - Insulation and Plasterboard & Drylining | |
|---|---|
| ORDER VALUE | DELIVERY CHARGE |
| Under £400 | £50 ex. VAT |
| Over £400 ex. VAT | £35 ex. VAT |
| Express Delivery - Timber & Sheet, Building Materials, Joinery and Gardens & Landscaping Products | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £300 | £50 ex. VAT |
| Over £300 ex. VAT | £35 ex. VAT |
Returns
We offer a 30 day returns policy on any faulty products.
Key Features
- {{home}} Use in ceilings, walls and floors
- {{local_fire_department}} A1 non-combustible
- {{volume_off}} Excellent acoustic and thermal performance
- {{build}} 600mm width to fit between studwork
Technical Specification
| Product: | Flexi |
|---|---|
| Material Type: | Rock Mineral |
| Thickness: | 90mm |
| Width: | 600mm |
| Length: | 1200mm |
| Pieces Per Pack: | 6 |
| Sales Unit: | Pack |
| Sales Unit Coverage: | 4.32m2 |
| Brand: | Rockwool |
| Manufacturer's Reference: | 123324 |
| Thermal Conductivity: | 0.038W/mK |
| Fire Rating: | A1 Non-Combustible |
Technical Downloads
Product Overview
Stone wool insulation slab, measuring 90mm in thickness and cut to 1200 × 600mm, for use in partitions and floors.
With a patented flexible edge, it securely friction fits within framed constructions, reducing the need for excessive cutting and limiting waste on site.
In a single solution, it provides reliable acoustic absorption, effective thermal insulation with a conductivity of 0.038 W/mK, and the highest level of fire safety (A1 non-combustible).
Its semi-rigid form allows straightforward handling and installation, while maintaining a close fit to minimise gaps that could compromise performance.
At 90mm thick, the slab delivers higher levels of both acoustic and thermal performance than slimmer profiles, while still maintaining a practical build-up depth.
This makes it well suited to partitions and floors where stronger sound insulation, greater heat retention, and assured fire protection are required.
Features & Benefits
- FLEXI Edge® along one side: Ensures snug, continuous fit in timber or metal frames, reducing gaps and air leakage.
- Non-combustible stone wool (Euroclass A1): Contributes to fire-safe wall, floor, and roof constructions.
- Effective acoustic absorber: Reduces airborne sound transmission through stud partitions and intermediate floors.
- Thermal conductivity 0.038 W/mK: Supports energy-efficient envelopes within framed build-ups.
- Will not slump, even if studs shrink: Maintains full fill and consistent performance over time.
- Easy to handle and cut: Speeds installation and fitting around services with minimal waste.
- Slab size 1200 x 600mm: Standard board dimensions suit common stud spacings.
- 90mm thickness: Provides effective noise control in thicker stud wall designs.
Applications
- Timber or metal stud partitions: Improves airborne sound reduction and thermal performance.
- Party walls in timber frame: Used within twin-frame/independent stud solutions to address acoustic and thermal bypass.
- Suspended timber floors: Laid between joists; supports sound control and U-value targets when used with appropriate membranes.
- Pitched roofs and warm/hybrid frames: Between rafters or as part of hybrid build-ups to enhance thermal continuity.
Installation Guidance
- Friction-fit installation: Flexible edge holds slabs tightly in place, reducing the need for mechanical fixings.
- Cut to fit with a sharp knife: Ensures minimal waste and precise fitting around services.
- Avoid gaps or voids: Maintains full thermal, acoustic, and fire resistance performance.
Compliance & Performance
- Reaction to fire classification A1 (EN13501-1): Fully non-combustible for high fire safety.
- Thermal conductivity 0.038 W/mK: Provides consistent insulation in framed constructions.
- High acoustic absorption: Tested to provide broadband sound reduction in lightweight partitions.
