Older buildings that have not been modified will be using more energy than their modern-day equivalents, which also means they cost more to run. Buildings like these are ideal for refurbishment for both aesthetical and regulatory reasons. Sound improvements are a key enhancement for any refurbishment project and there are acoustic insulation solutions available that can help achieve up-to-date specifications, meet building regulations and enhance the efficiency of that building.
Refurbishment – Reducing Installation Time & Overall Floor Depth
Unwanted noise travelling along direct and flanking paths can cause structural vibrations which in turn, causes the sound to radiate into other rooms within a building. Timber floors are generally problematic in resisting airborne sound transmission due to their lack of mass. By constructing a floating platform floor which isolates the walking surface from the basic floor structure under it, the refurb should achieve a significant reduction in noise travelling between floors.
The last ten to twelve years has seen the emergence and continued increase in usage of single deck, direct to joist acoustically insulating floor boards. This type of product is relatively easy to install and, by performing the normal structural functions as well as tentatively achieving the Approved Document E acoustic requirements for the change of use refurbishment, they present an attractive proposition. These boards normally consist of 22mm flooring grade chipboard bonded to a resilient layer which provides the acoustically separating bearing onto the joists.
When installing this type of flooring insulation solution, it is important that the floor heights are not drastically altered to incorporate the acoustic insulation, the product is quick/easy to fit and the amount of movement is marginal so that any bounce in the flooring is minimised.
Longevity & Resilience: PE/PUR Foam vs Rubber Back Boards
It is worth reflecting that prior to the event of the single-deck systems, the common construction which was deemed to meet the then (lower) acoustic requirements consisted of:
a) 18mm (min) chipboard or planks over the joists
b) Resilient layer
c) Floating 18mm chipboard deck or similar
Which together weighed 20 – 25Kg/m2 and was substantially heavier than 22mm chipboard with a PE or PUR expanded foam backing weighing 16 – 17Kg/m2.
With newer solutions, such as Isosonic Dek 30, the resilient layer consists of 8mm Isorubber with a density of 910Kg/m3, giving a total board weight of 22.3Kg/m2.
The tested versus actual under load and the long term (aged) impact sound absorption performance of light weight PE and PUR foams could also bear some scrutiny. Solid PE and PUR have densities of between 1000 – 1200Kg/m3, which means that the typically employed expanded foam of 35Kg/m3 density must be around 97% air/gas by volume; which, over a period of time and under load will defuse/deflate. This compaction leads to a loss of resilience; the ability to absorb impact sound energy.
Isorubber on the other hand is a very dense material with excellent energy absorption properties but undergoes no effective short term compression. This means that ‘what you test is what you get’ for the designed life span of the building.
Considering then that a domestic floor can be subjected to imposed loads in excess of 200Kg/m2 including partitions, and also that acoustic tests are inevitably carried out in the unloaded state, the question should be asked if the tests are truly representative of the real in use performance. It is always worth scrutinising test data to ensure that it truly represents performance in actual usage and that it will last for the expected duration of the usage.
Acoustic Insulation Solution for Single Deck Timber Floors
The Isosonic Dek 30 board has been designed specifically for this application. Testing against the fairly normal conditions of:
• 200mm deep joists at 400/500mm centres
• Masonry flanking walls
• 19.6Kg/m2 double plasterboard (fire resistant) acoustically decoupled ceiling.
The floor deck itself requires a mass of at least 21 – 22Kg/m2 in order to consistently meet the ADE minimum 43dB (DnTw+ctr) airborne sound transmission requirement.
This solution:
• Is a single fit structural floor and acoustic insulation
• Is free floating, glued T&G joints with no fixings to joints
• Uses a high density Isorubber (900kg/m2) layer to reduce noise transfer
• Is seen to limit the amount of movement in the deck and eliminate the ‘bounce’ that can be associated with soft foam acoustic layer based products
• Has engineered self-adhesive flanking insulation strip
• Has no long term or short term deformation of the acoustic layer
• Is suitable for use with under floor heating
If you would like to speak to one of our Technical Team about our refurbishment solutions, please either contact us directly on 01582 544255 or email us at [email protected]