Renovation of old wooden floors
Does your building have an uneven, older wooden floor?
This is how Granab subfloor systems solves acoustics and uneven surfaces
Renovating a property with older wooden joists often presents two recurring challenges: inadequate sound insulation and floors that have become uneven over time. Granab Floor Leveling System is designed to solve precisely these problems.
Why are older wooden floor joists problematic?
Wooden joists in older buildings rarely have the impact sound insulation required by modern sound classification standards.
After decades, it is common for old wooden buildings to have settled, causing the floors to become uneven. Wood also moves naturally with moisture and temperature over time. In buildings that are many decades old, this means that the joists are often no longer level. This creates problems both for the installation of new flooring and for the quality of the end result.
Casted subfloors – a heavy solution with major consequences
A common method is to pour concrete directly onto the wooden floor. This does provide a leveled surface and some acoustic performance, but at a high price.
Conventional concrete weighs approximately 100–300 kg per square metre, depending on thickness. For an older wooden floor that is not designed to bear this load, load-bearing walls or columns must often be added to the floor below – an intervention that is both costly and environmentally unfriendly. In the worst case, the floor may not be able to bear the increased load, which can lead to structural damage.
Benefits of the Granab system
The Granab system is easy to install and has many advantages compared to heavy, casted subfloors like concrete and levelling screeds
Documented acoustic performance on wooden joists
To make the installation of Granab as smooth as possible, the girders are designed and delivered pre-cut together with the associated drawing of both the girders and the floor ventilation. We have designed the material taking into account your wishes and your floor plan so that the system is tailored to your project. This means that you can start installing as soon as the material has been delivered and you do not have to deal with wasted material.
lightweight, sound-absorbing and height-adjustable
Granab Subloor System weighs only 5 kg per square metre. This makes it possible to install the system directly on existing wooden joists without having to reinforce the load-bearing structure. This is a decisive advantage in renovation projects where interference with the frame must be minimised.
The system’s variable construction height – from 30 mm up to 470 mm, with special heights up to 1,000 mm – makes it possible to compensate for unevenness and slopes in old joists. The joists are adjusted individually so that the floor is level regardless of how much the original substrate has moved.
Quick feedback and high availability
Our goal is to facilitate and streamline the preparation and installation process for our customers. You can always expect quick feedback and high availability. Our support team is available to help you and answer any questions you may have. We also follow up on the work and ensure that you are satisfied with the installation and that the Granab system lives up to your expectations.
Easy installation with pre-cut girders
To make the installation of Granab as smooth as possible, the girders are designed and delivered pre-cut together with the associated drawing. We have designed the material taking into account your wishes and your floor plan so that the system is tailored to your project. This means that you can start installing as soon as the material has been delivered and you do not have to deal with wasted material.
Dry and quick installation method
Unlike concrete casting, the Granab system does not require any wet processes. It is mounted directly onto the raw floor structure using wood screws – without chemical additives or long drying times. This shortens the project time and reduces the risk of moisture-related problems in a structure that may already be sensitive to moisture.
System 3000N is constructed with galvanised steel floor joists, which means that the system is not affected by moisture or temperature changes – an important feature in older properties where the climate in the joist space can vary.
Summary
Granab Subfloor System is an effective alternative to pouring concrete or other heavy dry screeds when renovating older wooden joist floors. Its low weight protects the existing load-bearing structure, its variable construction height handles unevenness, and its documented acoustic performance ensures that modern requirements for impact sound insulation can be met. Contact Granab for design assistance and technical advice for your renovation project.
FAQs – about Granab on older wooden joists
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Environmental certification
Granab works actively to reduce environmental impact and has certifications that confirm our commitment to sustainability. All our subfloor systems have Environmentally Product Declarations (EPD).
