Acoustic Floor Upgrades: Mineral Wool Insulation Between Joists

Floor insulation and soundproofing installation in progress, featuring mineral wool between joists and acoustic strip..

Exposed wooden floor joists fitted with mineral wool insulation and dark acoustic strip before the deck is laid.

The original floorboards have been stripped back to expose the timber joists. Thick mineral wool insulation has been friction-fitted between the joists to provide thermal and acoustic benefits. Dark resilient acoustic strips are visible running along the top of the joists to decouple the upcoming floor deck from the main structure.

Technical insight

Upgrading a suspended timber floor provides an excellent opportunity to improve both thermal and acoustic performance. Installing dense mineral wool between the joists significantly reduces airborne noise transmission and helps minimise heat loss. However, sound also travels through the solid timber structure itself (known as impact noise). To address this, resilient acoustic bars or isolation tapes are applied directly to the top of the joists before the new floor deck is laid. This vital decoupling layer physically separates the floor surface from the structural joists, dampening vibrations and dramatically reducing impact noise from footsteps.

floor insulationsoundproofingacoustic insulationmineral woolsuspended timber floorresilient barsfloor joistsretrofitacoustic decouplingnoise reduction

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