• Insulation Rolls vs Insulation Slabs: Which Type is Better in a Partition Wall

    | by Dave Ashbolt

    When it comes to insulating partition walls, the choice between insulation rolls and insulation slabs can be pivotal. Each option brings its own set of advantages and considerations to the table, impacting everything from thermal performance to installation ease. In this comprehensive guide, we delve into the nuances of this debate, shedding light on the pros and cons of insulation rolls vs insulation slabs as a form of partition wall insulation.

    Whether you’re embarking on a residential renovation or a commercial construction project, understanding the differences between these two insulation solutions is crucial for making an informed decision that aligns with your goals for energy efficiency, comfort, and cost-effectiveness.

    Let’s dive in and explore the intricacies of insulation rolls vs insulation slabs for partition walls.

    Insulation Slabs Explained

    Insulation slabs, crafted from materials like glass wool, rock mineral wool, or sheep’s wool, offer a rigid solution for insulation needs.

    Commonly referred to as insulation batts, these slabs boast impressive thermal and acoustic insulation properties, along with fire resistance, ensuring they won’t ignite or exacerbate fire spread.

    Thanks to their sturdy build, insulation slabs are notably simpler to install compared to loft rolls, especially for pitched roofs or upright walls. Their rigid structure prevents sagging or compression during installation.

    They are typically used in colder climates, as they provide more thermal value than rolls. They are also more dense, which makes them effective as acoustic insulation. However, they can be quite expensive and can take up a lot of space since they don’t compress very well. 

    Insulation Rolls Explained

    Insulation rolls, also known as blanket insulation or batt insulation, are flexible sheets of insulation typically made from fibreglass, mineral wool, or natural fibres such as cotton or sheep’s wool. These rolls come in various thicknesses and widths to accommodate different spaces and are designed for easy installation between framing members in walls, floors, and ceilings.

    They are less expensive than slabs and can be easier to install. However, they don’t provide as much acoustic insulation value as slabs as they are less dense.

    Now that you know the basics of each type of insulation, let’s compare.

    Why Use Insulation Rolls?

    Insulation rolls are a good choice for warmer climates or for homes that already have insulation in the walls. Insulation rolls are more flexible than slabs, so they can be adapted to fit different spaces and shapes. and are less expensive compared to insulation slabs. 

    However, they aren’t as effective in terms of acoustic insulation when pitted against slabs. Knauf provides a range of acoustic insulation rolls, again in thicknesses of 25mm, 50mm, 75mm and 100mm.


    • Flexibility: Highly flexible, allowing for easy handling and installation in tight or irregularly shaped spaces.
    • Customisation: They can be easily cut to size with a utility knife or scissors, enabling precise fitting around obstacles like electrical wiring and plumbing pipes.
    • Cost-Effectiveness: Often more affordable than other types of insulation, making them a budget-friendly option for large-scale projects.
    • DIY-Friendly: With their straightforward installation process, they are suitable for DIY enthusiasts, potentially reducing labour costs.


    • Compression: Improper handling or compression during installation can reduce their effectiveness by diminishing their thermal resistance.
    • Moisture Susceptibility: Certain types of insulation rolls, particularly fibreglass, may absorb moisture if exposed, leading to mould growth and compromised performance.
    • Air Sealing: Unlike thermal alternatives such as rigid insulation boards, they may not provide effective air sealing, potentially allowing for air leakage and energy loss.

    Why Use Insulation Slabs?

    Insulation slabs are denser than rolls which makes them perfect material to stop sound transfer.

    They are also easy to install and available in a variety of thicknesses to suit your needs. Rockwool RWA45 is the most popular slab, and comes in 25mm, 50mm, 75mm, and 100mm thicknesses.


    • High Thermal Performance: Typically provide superior thermal performance compared to insulation rolls. 
    • Structural Support: Their rigidity makes them ideal for insulating exterior walls and roofs where additional strength is required.
    • Moisture Resistance: Many types of insulation slabs exhibit excellent resistance to moisture. This reduces the risk of mould growth, maintaining insulation performance over time.
    • Fire Resistance: Certain insulation slab materials, such as mineral wool and polyisocyanurate (PIR), have inherent fire-resistant properties, enhancing building safety.


    • Limited Flexibility: Unlike insulation rolls, insulation slabs are less flexible. This means they may require more effort to fit into irregularly shaped spaces or around obstacles.
    • Professional Installation: Due to their rigid nature, installation of insulation slabs often requires precision cutting and fitting.
    • Cost: Generally have a higher upfront cost compared to insulation rolls, which could impact the overall project budget.


    Ultimately, the choice between insulation rolls and insulation slabs hinges on several factors, including the project’s requirements, available space, ease of installation, and budget considerations.

    For partition walls that prioritise flexibility, ease of installation, and cost-effectiveness, insulation rolls emerge as the preferred option. On the other hand, if structural support, soundproofing, or fire resistance is paramount, insulation slabs may be more suitable.

    Before making a decision, it’s advisable to carefully assess your project’s needs and consult with professionals if necessary.

    Choosing the appropriate insulation for your partition wall enhances its thermal performance, soundproofing, and durability, ensuring a comfortable environment.

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