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overscreed membrane

Why acoustic insulation is vital in concrete screeded floors

This guide will help you understand what is needed to help sound insulate concrete screed floors.

Do concrete floors need sound insulation?
What are the best products to insulate concrete floors?
What the building regulations demand?

Do concrete floors need sound insulation>

Concrete may be better than timber at reducing airborne sound transmission between the floors of
a building due to their significantly greater mass, but an acoustic membranes can play a key part of the specification to address nuisance impact sounds.

The density of concrete and masonry means it is a relatively effective reducer of airborne sound transmission, but impact sounds can still get through. The solution is to add a resilient layer across the floor surface to absorb the sound waves that transmits through the floor covering, such as tiles and wooden floors, then the concrete.

Hush Acoustics have designed both under screed and over screed rubber-based acoustic membranes that can be used with most floor finishes and work to provide a sound-reducing resilient layer.

These are designed be used within an appropriate floor design, providing additional sound insulation to isolate sound transmission paths, or – for a more effective solution – as part of one of Hush Acoustics’ fully tested acoustic flooring systems.

These expertly configured systems are designed to give architects and contractors peace of mind
that the acoustic insulation specification will meet the client brief, providing every element is
installed as recommended.

What are the best products to insulate concrete floors?

Amongst the acoustic systems available for screed floors is the HD1043 acoustic Over-screed solution, which offers a treatment for screed concrete slab floors. This utilises the Hush Over-screed Acoustic Membrane over the entire floor surface, bonded to the screed using Hush Contact Adhesive, with the added benefit of enhancing airborne sound transmission too via the Hush MF Ceiling system installed to the underside of the concrete structure.

By creating a clear 150mm void between the concrete slab and ceiling board below, Hush-Slab 100
Sound Absorber can be installed within the MF Ceiling System prior to installing a double layer of
12.5mm Soundbloc plasterboard.

Under-screed Insulation

Another solution that works in a similar way is the HD1042 Hush Under-screed 6 System. This is ideal
for floor constructions where there is an opportunity to install the acoustic membrane before the
screed is laid. There is also a version of this system specially for screed beam and block floors with the HD1047 Hush System Under-screed B/B.

The Hush Under Screed Membrane consists of a fine granulate of recycled rubber with a cork and PU
elastomer. Combining minimum build height with permanent resilience, it is suitable for numerous
applications including residential, industrial, educational, healthcare and the leisure sector, with
performance meeting the criteria of all UK Building Regulations, including Approved Document E
Similarly versatile is the Hush Over Screed Membrane which has been designed to isolate a screed
from the structure – also in line with all UK Building Regulations.

It is suitable for new build, conversion and refurbishment projects, and as an alternative solution to Robust Details acoustic membranes, and can be used to isolate a screed from concrete structures, concrete planks, raft structures, combined concrete/metal structures and beam and block.

What the Building Regulations demand

In England and Wales under Approved Document E, the minimum level of airborne sound resistance for dividing floors between homes is 45dB (decibels) in new builds and 43dB in conversion projects. The requirement for impact sound, such as footsteps or dropped objects, stipulates a maximum sound transmittance level of 62dB in new builds and 64dB for conversion projects.
In Northern Ireland the figures are the same, but in Scotland the minimum for airborne sound is 56db and a maximum of 56db for impact sound. Slightly different requirements apply to ‘traditional buildings’ built pre-1919.

There are no directly equivalent standards for non-domestic buildings, but certain applications do require measures to be taken to address sound transmission and acoustic comfort, such as in schools and hospitals. But it is also good practice to ensure separating walls and floors are also acoustically insulated to a high standard in commercial or public sector applications where noise between properties or rooms could be a nuisance – hotels and some offices, for example.

You can read more about what the Building Regulations require using these links:

England & Wales – Approved Document E
Scotland – Building Standards technical handbook 2017 Section 5: Noise
Northern Ireland – Technical Booklet G

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