SoundPro solutions for separating floors
(New build) E1 & Robust details
A separating floor is defined as a floor that separates adjoining dwelling houses, flats or rooms used for residential purposes.
Section E1 of the Approved Document E (ADE Section 3) introduces performance criteria for separating walls. The minimum value for airborne sound insulation is:
Airborne Sound DnTw + Ctr +45 dB (or greater)
Impact Sound LnTw =62 dB (or less)
Section E1 of Part E document deals with the protection against sound from other parts of the building and adjoining buildings; Dwelling houses, flats and rooms for residential purposes shall be designed and constructed in such a way that they provide reasonable resistance to sound from other parts of the building and from adjoining buildings.
The Part E requirement for separating floors is subject to both airborne and impact sound regulations. Pre-completion site testing is also required.
Robust details
Compliance with Robust Details will negate the requirement for pre-completion site testing of new build separating structures for dwelling houses and flats.
Robust Details are based upon meeting sound test values which are in excess of those required by Approved Document E.
Each robust detail has its own site work checklist. They are designed to help builders ensure that the building work is carried out to robust detail specifications, they can also be used by Building Control Bodies, new home warranty providers and others.
Rockwool Limited has been actively involved with the robust detail process, both with the House Builders Federation, house builders and Robust Details Ltd. Full details on how the scheme works is available on the website www.robustdetails.com/
All robust details have a significant safety margin built into the constructions so that they would be highly unlikely to fail to meet ADE requirements. All robust details must have achieved a minimum requirement (by site testing at least 30 times) a mean airborne of DnTw + Ctr of 50dB (5dB higher than ADE), with no individual value lower than 47dB, and an impact requirement which has achieved a maximum value of L’nTw of 57dB (5dB lower than ADE) with no individual value higher than 60dB.
Flanking sound
A major cause of reduced acoustic performance in separating floors is due to flanking paths via the surrounding structure rather than a direct path through the floor. Good practice detailing at the design stage, especially at key junctions, together with good workmanship will minimise this effect and optimise performance levels. Guidelines of good practice detailing at key junctions are provided throughout the new Approved document E.
Junctions with floor penetrations
Pipes and ducts that penetrate a floor separating habitable rooms in different flats should be enclosed for their full height in each flat.
The enclosure should be constructed of material having a mass per unit area of at least 15Kg/m2 (eg 2 x 12.5mm standard plasterboard)
- Either line the enclosure with 50mm Rockwool Flexi, or wrap the duct or pipe within the enclosure with 25mm Rockwool Techtube.
- The enclosure may go down to the floor base if isolated from the floating layer.
- Penetrations through a separating floor by ducts and pipes should have fire protection to satisfy Building Regulation Part B – Fire Safety. Fire stopping should be flexible and also prevent rigid contact between the pipe and floor. Rockwool Insulated Fire Sleeve meets these requirements.
