Knauf Rocksilk Flexible Slab

Knauf Rocksilk Flexible Slab is a rock mineral wool insulation slab used for acoustic, thermal, and fire-safe building insulation. It is made with Knauf’s ECOSE® binding technology, a low-VOC, bio-based binder that enhances indoor air quality and makes the material comfortable to handle.

What Is Rocksilk Flexible Insulation?

Rocksilk Flexible insulation is a slab consisting of rock mineral wool spun into dense, springy fibres offering thermal conductivity of around 0.035–0.037 W/m·K. Its open-fibre structure absorbs airborne sound to improve acoustic performance in walls and floor build-ups. Rocksilk slab is Euroclass A1 (non-combustible) and reduces fire spread.

What Is Rocksilk Flexible Slab Used For?

Knauf Flexible Slab can be used in various ways:

• In metal or timber stud walls to reduce heat loss and minimise sound transfer.
• Between timber floor joists to improve thermal and acoustic insulation.
• To insulate pitched roofs, lofts, or ceilings as part of a ventilated or warm-roof build-up.
• Acoustic absorber in separating walls and floors – Reduces sound transfer between rooms.

FAQ

Where to buy Rocksilk Flexible Slab?

You can buy Rocksilk Knauf Flexible insulation online from Insulation Wholesale. We offer a wide range of thicknesses and supply to both trade and DIY customers. All our Rocksilk slabs are available at competitive prices with quick delivery options. Our team handles quantities, quotes, and order support, making the process straightforward from checkout to delivery.

How to fix Rocksilk Flexible insulation?

1. Measure the joist or stud spacing.
2. Cut the slab slightly oversize and fit it gently until it touches both sides of the framed space without being compressed. Compressing the wool lowers its performance.
3. Butt the joists tightly so there are no gaps.
4. Install a vapour control layer or lining board if your build-up requires it.

Wear basic PPE when cutting or handling to avoid irritation.

Why choose Rocksilk Flexible insulation?

Knauf Rocksilk offers multiple benefits:

• It is Euroclass A1 non-combustible, giving strong fire safety performance.
• The low thermal conductivity helps meet Part L energy-efficiency requirements.
• Its flexible edges self-adjust within the cavity, eliminating gaps.
• Its durable fibre structure keeps its shape and performance over time.
• ECOSE® binding technology makes it friendlier to work with than older binders.