Insulation in combination with Granab Subfloor System

The right insulation combined with Granab subfloor system is important for achieving optimal sound insulation.

Granab subfloor system offers complete flexibility in terms of insulation choice, allowing you to tailor the solution to the specific requirements and budget of your project.

Granab does not sell insulation, which gives you, as a builder or designer, complete freedom to choose the insulation that best suits your project. Regardless of which insulation material you choose, it can be combined with our subfloor systems.

However, we recommend that you inform us of the insulation material you plan to use, as the density of the insulation can affect the acoustic properties of the entire floor structure.

By knowing your insulation choice, we can ensure that the final solution optimally meets the project’s sound requirements.

There are several proven insulation materials that work excellently in combination with the Granab system. Each material has its own unique properties that make it suitable for different projects and requirements.

Cellulose insulation

Cellulose insulation is a recycled insulation material made from newspaper that is ground down into fibres and treated with fire-retardant mineral salts. The material represents a sustainable choice with a very low carbon footprint.

One of the main properties of cellulose insulation is its high density, which provides excellent airtightness and effectively counteracts convection.

Cellulose insulation is hygroscopic and can buffer moisture and then dry out, which helps to protect the frame from moisture-related damage and enables diffusion-open wall and ceiling constructions when these are correctly dimensioned and designed.

Wood fibre insulation

Wood fibre insulation is made from forest industry waste products, usually spruce chips, and is a renewable and recyclable insulation material. Its relatively high density reduces air movement in the insulation, providing good thermal insulation in the structure and effective sound insulation between rooms and floors.

The material is hygroscopic and can absorb and release moisture depending on the relative humidity, which provides a moisture-buffering effect and reduces the risk of condensation in well-designed structures. Wood fibre insulation has low self-convection and thus limited air flow in the insulation layer, which counteracts heat loss through convection.

The insulation is fire-retardant treated so that it chars in the event of fire instead of melting, which results in a more controlled fire and predictable fire-technical properties.

There are two main methods for installing insulation in combination with Granab subfloor system:

Insulation boards are placed between the floor girders/beams, providing a controlled and predictable installation. This method is particularly suitable for renovation and conversion projects where material handling needs to be clear and structured.

Loose-fill insulation is sprayed into the space between the girders/beams, providing effective coverage even in hard-to-reach areas without joints or gaps. This method is particularly suitable for larger projects and new builds where seamless insulation without thermal bridges is a priority.

The need for insulation in the Granab floors varies depending on the type of floor structure. Insulation is primarily relevant for CLT floor structures and is recommended in order to optimise acoustic properties and achieve the desired sound class. Insulation between girders/beams is less often necessary for concrete-based floor structures.

Would you like to know more about how Granab subfloor systems could suit your project? Contact us for technical advice and help with project planning. We will help you choose the right solution based on your specific needs and requirements. With our experience and knowledge of acoustics in floor constructionsg, we ensure that you get a solution that meets all technical and aesthetic requirements.