How to Soundproof around an RSJ

What is an RSJ?

A rolled steel joist (RSJ) is a common type of structural steel beam which is often used in construction, It is also known and typically referred to as a ‘H beam’ or an  'I-beam' due to their cross sectional shape, they can come in a variety of standard sizes and wall thickness’ dependant on their application and strength requirements.

What is the purpose of an RSJ?

When a supporting wall is removed, you will need something in its place. In this instance you may need to put in its place a rolled steel joist (RSJ) beam. This will then be able to support the floor area above. A qualified builder or structural engineer would be able to advise further from the initial design process to installation.

Our Suggested Build Up to Soundproof your RSJ

We would suggest using a boxing-in method to soundproof your RSJ which completely conceals and encases the steel beam in a variety of materials.

If you are soundproofing your ceiling, you will need to minimise the level of sound energy being transferred through the structure, from the initial source of the sound energy which is created on the floor above and therefore causing the steel beam (RSJ) to vibrate.

Step 1 (optional but will boost results): We would recommend covering the RSJ with FlexiSound 5. When bonded or adhered to hard materials the viscos-elastic properties reduce the sound resonance / vibration typical of hard materials, resulting in a higher performance material compared to Mass Loaded Vinyl and Green Glue combined.

Step 2: Boxing around the RSJ using timber stud framework (leaving a minimum of a 5mm gap between the wood profiles and RSJ to minimise flanking noise transferring through the hard materials).

Step 3: Fill the gaps around the RSJ, and in between the studs with very dense Acoustic Mineral Wool. This Mineral Wool is designed to offer the highest level of sound absorption in the cavity partitions between timber and metal studs, and significantly improving acoustic performance and reducing reverberation.

Step 4: fixing 15mm Acoustic Plasterboard to the outside of the studs to box in the area. You are then able soundproof around this area with either an additional layer of acoustic plasterboard or the ReductoClip Ceiling System as you would the rest of the ceiling, dependant on the extent of the soundproofing performance which you are planning to achieve.