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Rockwool Flexi Insulation

Rockwool Flexi Insulation Slab – 50mm (Pack/12 – 1200mmx600mm)

 Rockwool FLEXI®

Rockwool Flexi Insulation® Rockwool Flexi Insulation has been designed as a multi-use, dual-purpose acoustic and thermal mineral wool insulation with a unique flexible edge along one side. The FLEXI slab is manufactured with the patented flexible edge which ensures a perfect fit is maintained between the insulation and the supporting framework.

The insulation can be fitted between fresh timber. And will expand into the wider space as the timber dries out and shrinks back. Other types of insulation can often become displaced resulting in cold spots or poor acoustics. FLEXI provides excellent thermal. and acoustic performance as well as being A1 classified non-combustible for fire resistance.

ROCKWOOL FLEXI® is easy to install and has optimum effectiveness. It is suitable for use all over the home, in pitched roof rafters, framed external walls, internal partitions, intermediate floors, separating walls and floors, and timber suspended ground floors.

Thickness: 50mm
All Thickness: 50,60,70,90,100,120,140,180mm
Width: 600mm
Length: 1200mm
Pack Quantity: 12
Pack Coverage: 8.64m2
Density: 33kg/m3
Weight: 15.12kg
Thermal Conductivity:  Thermal – 50mm – 120mm, 0.038 W/mK – Acoustic – 140mm – 180mm, 0.035 W/mK
Thermal Resistance: 1.32m2K/W
Fire Rating (Reaction to Fire): A1(Non-combustible)
Acoustical Performance: Achieves Part E (resistance to sound) when installed in accordance to ROCKWOOL guidelines    
Water repellent: Water Repellent    
Water vapor resistance: Negligible     


• Outstanding thermal, acoustic, and fire properties
• FLEXI Edge® ensures tight friction fit
• Will does not slump, even if studs shrink
• Range of thicknesses and widths to suit multiple applications
• Non-combustible – Euroclass A1


ROCKWOOL FLEXI® is a multi-use, thermal, acoustic, and fire insulation product with a unique flexible edge along one side. The patented flexible edge ensures a perfect fit is maintained between the product and its supporting framework for easy installation and optimum effectiveness. FLEXI® is suitable for use between frames in walls, partitions, floors, and roofs, without the need for cutting or waste. Made from renewable volcanic rock, it is extremely fire resistant and significantly reduces the carbon footprint of a building.


ROCKWOOL FLEXI® is suitable for use in a wide range of applications, including acoustic and fire insulation for partitions, separating walls and floors, as well as thermal insulation for suspended floors, walls, and roofs.

ROCKWOOL FLEXI is available in a range of thicknesses and widths, with thermal conductivity of 0.038 W/mK, and 0.035 W/mK at 140mm thicknesses and above
-Fire classification
ROCKWOOL FLEXI® achieves a reaction to fire classification of A1, as defined in EN13501-1.
-Thermal applications – timber frame walls
The additional thermal benefits offered by using high-performance (HP) breather membranes (BM) and vapor control layers (VCL) over standard membranes are shown below.
-Effective thermal resistance (R-values) comparisons used for external cavities are as follows:

a. Standard BM =0.18m2K/W: or
b. Tyvek Reflex BM = 0.540m2K/W
c. Protect TF200 Thermo = 0.77m2K/W
Effective thermal resistance (R-values) comparisons used for service void cavities are as follows:

a. Standard VCL =0.18m2K/W: orb. DuPont AirGuard VCL = 0.680m2K/W
c. Protect VC Foil = 0.78m2K/W

As an environmentally conscious company, ROCKWOOL promotes.

Sustainable production.

and use of insulation and is committed to a continuous process of environmental improvement. All ROCKWOOL products provide outstanding thermal protection as well as four added benefits
-Fire resistance
-Acoustic comfort
-Sustainable materials

Health & Safety
The safety of ROCKWOOL stone wool is confirmed by current UK.

And Republic of Ireland health & safety regulations and EU directive 97/69/EC: ROCKWOOL fibers are not classified as a possible human carcinogen.
A Material Safety Data Sheet is available.

And can be downloaded from www.rockwool.co.uk to assist in the preparation of risk assessments, as required by the Control of Substances Hazardous to Health Regulations (COSHH).

Rockwool Flexi Insulation Slab – 50mm (Pack/12 – 1200mmx600mm)

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