Mineral Wool Insulation

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Mineral wool insulation, also known as known as mineral fiber or mineral cotton, is the dependable choice for those wanting to reduce sound and heat transmission in their homes. Not only does it absorb sound energy, but it also saves energy whilst improving the acoustic and thermal performance of walls, floors and roofs. Aside from its insulating properties it also provides excellent in-built fire protection. We offer the best mineral wool insulation slabs on the market from leading brands like Knauf and Rockwool.

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What Is Mineral Wool Insulation? 

With thermal, acoustic and fire preventative properties, Mineral Wool insulation stands as a robust insulation solution promising high performance over the lifetime of a build.

Derived from natural and recycled materials, mineral wool insulation is a product born from molten basalt rocks and slag, a byproduct from steel mills, which are spun into a fibre-like structure similar to wool, hence the name.

Highly versatile, mineral wool insulation can be used in various parts of a building, including walls, roofs, floors, and industrial applications. Its flexibility allows it to fit into irregular spaces, enhancing its insulation capabilities.

Rockwool Mineral Wool Insulation

Composed of renewable volcanic rock (a naturally poor sound conductor), Rockwool Mineral Wool Insulation slabs are especially effective at sound-dampening. Particularly Rockwool's RWA45 Slab.

Composed of very little solid material, with its primary structure being a complex network of porous fibers, this unique construction allows it to serve as an excellent choice for soundproofing. 

This acoustic performance is highlighted in the range's product code. The RW stands for “Rockwool”, A stands for “Acoustic” and the 45 refers to the fact that these slabs have a density of 45kg/m3 and 0.035 W/mK thermal conductivity. You can install these thermal and acoustic insulation slabs in partition walls or under floorboards.

The Rockwool Flexi Slab is another popular option for people after excellent acoustic sound insulation. Each mineral wool insulation slab is fitted with a flexible edge, meaning they can be friction fitted to almost any framework. 

All in all, Rockwool RW slab products offer outstanding fire, acoustic and thermal insulation properties. 

Knauf Mineral Wool Insulation

Like Rockwool, the Knauf Earthwool RS range contains premium quality rock mineral slabs to suit every insulation need. 

They are manufactured using Knauf’s unique ECOSE technology; a bio-based binder that contains no added formaldehyde or phenol, meaning the resulting slabs create much lower levels of dust than other slabs and are beautifully soft and easier to handle.

The bio-binder creates a natural brown colour that is distinct from the usual yellow colour of insulation. 

We recommend Knauf Earthwool RS products for people who need to insulate internal partitions, timber and metal studs, with the added comfort that ECOSE technology provides.

Mineral Wool Insulation Key Benefits 

  • Fire resilience - Euroclass A1 non-combustible
  • Temperature maintenance
  • Noise reduction properties
  • Robustness 
  • Sustainability
  • Water repellent and vapour permeable


How Mineral Wool Works As Acoustic Insulation

Porous materials, like mineral wool, help manage and diminish sound by permitting air to flow through their structure.

Its fibres are intricately interwoven, forming a dense network that contains numerous tiny pockets of air.

These air pockets within the material effectively trap sound waves, causing them to bounce, deflect, and ultimately dissipate within the wool's mineral fibre. 

By slowing down the passage of these waves, mineral wool helps to reduce the amount of sound that can pass through a wall, floor, or ceiling where it's installed.

Mineral Wool Insulation Thermal Conductivity

Mineral wool, also known as rock wool or stone wool, is made from a selection of raw materials, such as stone and glass. Mineral wool insulation thermal conductivity varies from product to product. Rockwool RWA45 Acoustic Slabs have a low thermal conductivity value of 0.035 W/mK, whereas Rockwool Flexi Acoustic Slabs have a thermal conductivity of 0.038 W/mK.

Frequently Asked Mineral Wool Insulation Questions

Mineral Wool Insulation vs Fibreglass

For many decades, fibreglass insulation (also known as glass wool insulation or glass mineral wool) was the standard for home construction. So what are the main drawbacks?

First off, fibreglass is sourced from non-renewable materials, specifically plastic reinforced with glass fibres. Fibreglass Insulation is made from up to 30% of recycled glass, like Knauf DriTherm 37 (which is specifically designed for installation in external masonry cavity walls). Secondly, fibreglass insulation has been linked to adverse health impacts, including irritating the skin, eyes, and respiratory system.

However, mineral wool and fiberglass exhibit a notable similarity in their composition and function. Specifically, glass and stone mineral wool insulates by capturing and retaining air within its intricate structure, thereby offering efficient thermal and acoustic insulation for various applications.

Let's consider the properties and differences between glass and stone mineral wool:
●     Eco-friendly - Mineral wool is made of up to 80% recycled content, whereas fibreglass is only made from up to 30%.
●     Weight - Mineral wool insulation slabs are far heavier than fibreglass slabs. They do not bend or sag as easily as fibreglass insulation slabs.
●     Installation - Firm mineral wool slabs can friction-fit into place between studs and joists. Installing fibreglass can be more complicated because it requires staples and/or wires.
●    Fire resistance - Both fibreglass and mineral wool insulation are classed as A1 non-combustible on the Euroclass scale, which means that they do not burn.


How to Cut Mineral Wool Insulation Material

Mineral wool slabs are soft and easy to manipulate. Despite the slabs being dense and thick, you can handle them with ease. There are a few different ways to cut mineral wool that does not require expensive equipment. One of the most popular ways to cut mineral wool slabs is with a serrated blade or with a woodcutting handsaw.

The first step is to mark the measurements on your slab. Marking measurements can reduce the possibility of mistakes. Once you have marked your measurements, you can begin cutting or sawing. It is important to cut insulation in a clear, open environment. You should also use safety equipment like goggles and aprons.

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