Tag: tips

Perimeter Isolation Strips: What Are They & How Do You Install Them?

Click Here to Go Straight to the Installation How-To If you’ve ever been in the market for an acoustic underlayment, you’ve probably been reminded to use perimeter isolation strips in conjunction with the mat. And you probably didn’t. It’s okay, you’re not alone.  I’ve come across so many people- from amateur DIY-ers to professional contractors- who don’t think this extra step is necessary or worth the additional cost or effort.  On the contrary, for just a little bit of extra effort and for an additional $0.25 or so per linear foot, you will be safeguarding the effectiveness of your investment in acoustical insulation.  Here’s why you need perimeter isolation strips: Acoustics Question: What’s the speed of sound in air?Answer: 1130 feet per second. That’s fast, right?  But what’s faster is the speed of sound in common building materials!  Once sound gets into the structure of your building, it will be traveling 10-15 times faster than it does through air.  Take a second to consider how fast that is.  When you are having a face-to-face conversation, how would you describe how quickly you hear them?  The word immediately comes to mind for me.  So, if immediate can be used to describe something traveling at 1130 feet per second, what does something traveling at 16,000 feet per second mean?  If you’re in the business of multifamily homes, high turnover, complaints, and even lawsuits might come to mind.  All this is just to show you that structure-borne sound transmission can be incredibly difficult to contain.  So in this case the old adage rings true: (more…)

Sound Advice: Sound vs. Noise

It’s something that I did not understand after earning a master’s degree in mechanical engineering with a concentration in acoustics. Neither did I get it during my time working in the noise group at Boeing Commercial Airlines. Even in my first year as an architectural acoustic consultant, I didn’t really get it for a while, much to the chagrin of my boss. It’s the reason for the quotation marks around the word noise above. It’s not complex or difficult, but it is subtle. It’s the difference between “sound” and “noise.” I first took note of this distinction when my old boss would edit my reports.  Almost every time I wrote “noise” she would change it to “sound” and say, “Noise is subjective.”  Initially I thought she was just being nit-picky, but eventually I got it. Take the timeless example of a classical music-loving parent who doesn’t understand their teenager’s taste for loud rock music.  To some, it may be the most epic guitar solo of all time, and yet to others, simply noise. It isn’t always so easy to make the distinction between sound and noise.  In architectural acoustics, a high background sound level might be considered noisy in some cases, or it may have been intentionally designed that way in others. (more…)

Need to reach a certain IIC rating? Read this before you contact an acoustic consultant.

This is something that comes up every day in my line of work: IIC [and STC] ratings of floor-ceiling assemblies.  I get calls from homeowners, architects, contractors, developers, product distributors- pretty much anyone involved in flooring whether they’re on the design side, sales side, or construction side.  Almost always, it goes the same way: Customer: I need to reach IIC — (usually it’s a 50 to reach code minimum, but sometimes it’s a 60). Which underlayment should I use? This is where I try my hardest not to sound disinterested or condescending, because I really don’t feel that way- it just requires a conscious effort not to sound robotic when you’ve gotten used to asking the same questions.  Chances are, other acoustic consultants may have a similar experience, so here’s some sound advice to prepare yourself with before you contact an acoustic consultant. IIC and STC ratings are dependent on entire assemblies, not any single element. This means that you’ll need to have all of the details of your floor-ceiling assembly before you can expect real advice from an acoustician.  Ideally you’ll have an architectural drawing calling out each element and it’s thickness in the assembly, but if not, I usually email a list like this for them to fill out: – Floor Finish – Underlayment – Subfloor system (concrete slab?  wood joist?  truss?  spacings, thicknesses, gauges, etc.) – Batt insulation in the ceiling cavity? – Resilient channels? – Ceiling details (material, number of layers, thicknesses?) The science of predicting (more…)