Insulation for Timber Joist Separating Floors

The primary purpose of a separating floor is to provide acoustic separation for both airborne and impact sound between two adjacent dwellings, thereby improving the acoustic comfort of both dwellings.

The minimum permitted acoustic specifications are defined by Approved Document E (England & Wales) and Section 5 (Scotland), although it is often recommended to improve on this where possible.

One of the methods to demonstrate achieving this is to use Robust Details, alternatively an acoustician can be tasked with verifying the design of a separating floor.

The insulation of choice for timber separating floors is typically a glass mineral wool (GMW) roll or slab. Isover Acoustic Partition Roll (APR 1200) can be installed as part of the separating floor construction between the joists/I-beams and also, depending on the choice of floating floor treatment, between the resilient battens above the sub-deck to provide the level of sound reduction required according to Approved Document E (England & Wales) and Section 5 (Scotland).

Key Considerations

When using Isover products, you need to satisfy yourself that use of the product meets all relevant national Building Regulations and guidance as well as local, national and other applicable standards relevant for your construction or application, including requirements in relation to fire and applicable height restrictions. In addition to the product datasheet, please refer to the following product documents:

• BBA certificates - where applicable to the application
• Declarations of Performance
• Health & safety datasheets

The building detail is for illustrative purposes only. It does not constitute advice and should not be relied upon.

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Insulation products

Product Name	Thickness Range	Sizes	Lambda
Isover Acoustic Partition Roll (APR 1200)	25-100mm	Width 2 x 0.6m, Length 9.17 - 20m	See datasheet
Isover Acoustic Slab	50-100mm	Width 600mm, Length 1200mm	See datasheet