Under the screed

// the building envelope

As consumers, built-in obsolescence and disposability are not only concepts we’ve come to accept but, in some instances, they’re something we’ve come to demand. No sooner has the iPhone 6 wowed consumers, dominating tech headlines, than rumours begin to circulate about the iPhone 7. Microsoft have gone one further, with Windows 8 soon to be superseded by Windows 10. Windows 9 didn’t even make it to market before being declared obsolete!


Buildings, on the other hand, are expected to last. That’s why brick, steel, concrete and glass dominate the construction materials marketplace. These are materials we place high demands upon. Take concrete, for example. Other than the odd chip and a bit of wear and tear, we expect it to last many decades without losing any of its physical integrity. When concrete screed is laid down, we expect it to stay down for as long as the building is standing.


But what about what’s under the screed? If, once laid down, the screed must stay down, surely the same longevity must be demanded of the products that sit beneath the screed. Such as acoustic underscreed material. Unlike the materials mentioned above, acoustic underscreed products are, by necessity, soft. A hard material would do nothing to prevent the transmission of sound. But just because a material is soft doesn’t mean it can’t be tough. Consider the fact that a cubic metre of screed weighs approximately 2.3 tonnes and you’ll have some idea just how tough this soft material has to be.


The particular kind of toughness demanded of acoustic underscreed products is compression strength. In a nutshell, this is a construction material’s ability to retain its thickness when subjected to continuous physical force from above; for example, from a great weight, such as 2.3 tonnes of screed. The thickness of an acoustic underscreed material is a significant factor in its performance as a soundproofing layer. If, as a result of being subjected to a significant load over time, it becomes thinner, it will no longer deliver the acoustic performance for which it was doubtless originally specified.


As this compression takes place over time, these products and, by extension, the buildings themselves, will pass even the most rigorous and demanding of Building Control inspections, because, at completion and for some time after, the products work perfectly. It’s later that the problems will emerge; it is later that residents may start to complain of poor soundproofing, sleepless nights and a reduced quality of life. And quality of life is integral to the success of any social housing project.

 

So, when selecting an acoustic underscreed material, data supporting the long-term compression strength of the material should be sought. CMS Danskin’s range of Regupol acoustic underscreed resilient layers all offer good compression strength: Regupol Quietlay, Regupol E48, Regupol 6010BA, Regupol 6010SH and Regupol 7210C. Regupol E48, for example, a recycled rubber crumb product, when subjected to 3 to./m2 for 10,000 minutes registered slightly over 2mm of compression, whereas an acoustic foam product used for similar applications suffered more than 7mm of compression. To put things in perspective, 10,000 minutes is just shy of one week. Imagine how things would be a year down the line, or two years. It won’t be long before increasingly vocal and legislation-savvy tenants start questioning the noises from above.


We expect our buildings to last. We should expect no less of our acoustic materials.

View The Latest Issue