FHB Logo Facebook LinkedIn Email Pinterest Twitter Instagram Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe

In every issue you'll find...

  • Expert insights on techniques and principles
  • Unbiased tool reviews
  • Step-by-step details to master the job
  • Field-tested advice and know-how
Subscribe Now!
Subscribe
  • How-To
  • Design
  • Tools & Materials
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
  • Join
  • Log In
Subscribe

Discussion Forum

Discussion Forum

Sound proofing with Insulation

rdg732000 | Posted in Energy, Heating & Insulation on April 6, 2011 06:49am

I am remodeling the first floor of my 2 family home and have a tenant living  upstairs. I want to sound proof the ceiling of the first floor apartment . I’ve been told that open-cell spray foam insulation is very good for soundproofing. Would using open-cell spray foam be a significant improvement over batt insulation?  Also, what thickness of each kind of insulation would be best if the space to be filled is 8 inches deep?

Reply

Replies

  1. calvin | Apr 06, 2011 08:08pm | #1

    I cannot give you all the answers

    but I'll try for one with this suggestion.  Mass is important.  You can acheive that with what you attach below any insulation you use.  De coupling the joists from what the finish is attached to is also important.  Using resilient channel and two layers of drywall, or channel and one layer of homasote topped by drywall will do much to improve your noise reduction.

  2. sirhc16 | Apr 06, 2011 10:53pm | #2

    How to Soundproof a Wall Separating a Bedroom From a Family Room  This video has some good info on soundproofing: 

     

      

     

  3. Clewless1 | Apr 07, 2011 08:54am | #3

    I agree w/ others ... insulation alone isn't all you should consider.

    A "standard" code option for your case would be hat channels running perp to joists and two layers of drywall. When I did my house w/ a basement apartment, that is what I HAD to do. This technique combines the mass w/ the isolation that someone mentioned. Isolation using the hat channels perp to joists. Mass using extra drywall.

    You might talk w/ the building official. There's a whole list of options for sound separation of e.g. apartments like this. Personally, I wouldn't do the expense of foam insulation ... although I'm not a sound expert. If you are going to spend the money, I'd use sound batts ... I think they are made w/ rockwool insulation as maybe your best choice ... it's the standard in the commercial industry. Or you could use the foam they install in anechoic chambers.

  4. TedWhite | Apr 07, 2011 09:52am | #4

    DanH has some good info there. I would caution everyone regarding the contents of that video. Quite a few classic errors in it:

    • The wall framing is "coupled" and therefore not as effective in stopping the bass frequencies.

    • Given that the wall is coupled, the thing to do would be to frame at 24" OC, not 16"

    • The floor, side walls and ceiling will allow sound to travel around the wall in question. This is callled Flanking: http://www.soundproofingcompany.com/library/articles/flanking/

    • There are huge vents in the gable that will conduct sound easily. Right past the drywall.

    • Spray foam is well known and well documented to be about the worst thing to put in any sound isolated wall. http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/ir/ir693/ir693.pdf

    • The specialty drywall ($80 a sheet) used will yield a relatively low mass solution, and mass is a main part of any isolation slution. Better to have used standard ($8 a sheet) 5/8" drywall.

    • Lastly, this entire treatment would have performed much better if installed on the sound producing side of the wall, thereby reducing the sound from entering the wall framing in the first place.

    1. Clewless1 | Apr 09, 2011 08:56am | #7

      "Lastly, this entire

      "Lastly, this entire treatment would have performed much better if installed on the sound producing side of the wall, thereby reducing the sound from entering the wall framing in the first place."

      That would have been good ... if it had, in fact, been a wall ... the question was about a ceiling.

  5. Tim | Apr 08, 2011 03:44pm | #5

    Rock-Sol and resilient channels

    I am in the process of doing exactly the same thing in my duplex. My wife is the Architect and know the specific numbers better than I, but this is the gist of it.

    No foam. Use batts. Rock wool is best and adds more fire resistence than most other insulating products. Unfaced fiberglass is the next best choice.

    Resilient channels and 5/8" GWB, as Dan correctly pointed out, a very important part of this assembly. All items make a difference, but individually not that much. It is a system, and when installed as such, works best.

    Good luck.

  6. TedWhite | Apr 08, 2011 03:47pm | #6

    I would reconsider the RC channel...

  7. DanH | Apr 09, 2011 09:21am | #8

    It's a common fallacy to believe that what makes good thermal insulation makes good sound insulation -- there's really very little connection between the two.

    The three critical components of sound "insulation" are mass, damping, and isolation.  Mass is simply that -- weight.  Damping means something that is "gooey" -- something that bends when you apply pressure but only slowly returns to its original shape when you remove the pressure.  Isolation means effectively putting soft springs between the surface facing the noise and the surface on the other side.

    Which combination of these features should be used in a given situation depends on the nature of the noise (eg, high frequency or low frequency) and the practical issues of thickness, weight, and expense.  In a floor/ceiling situation (where you're trying to keep the bottom floor quiet), the main issue is footsteps, and footsteps have a strong low-frequency component.   Low frequencies are easily transmitted through the floor joists, so the main target of your work should be isolating the ceiling from the floor joists.  This is best accomplished with resilient channel (springs) and heavy (eg two layers) drywall (mass).

    [I'll add that in the above triad, things like fiberglass insulation do the damping.  True, fiberglass isn't "gooey", but air, flowing through lots of tiny spaces, is (it has viscosity).  The sound waves (waves of air movement) flowing through the fiberglass result in turbulence which dissipates energy.  This is why foam isn't such a great sound insulating material -- no air movement.

    The other relatively easy way to add damping is with layers of relatively stiff sheet material (metal, plastic, drywall) joined by a viscous adhesive.  In aircraft, for example, layers of metal foil joined by an adhesive much like rubber cement are used for vibration and sound control.  Such a solution requires some degree of "tuning" to get the right combination of sheet stiffness and adhesive viscosity, so they're not generally usable in non-engineered situations.  However, there are simple cases (such as vibrating ductwork) where, eg, a piece of vinyl flooring glued to the duct can be effective.

    There probably also are resilient channels made with an included damping material (ie, a sort of rubber).  Whether these can add enough damping to have any real effect is questionable, however.]

  8. TedWhite | Apr 09, 2011 09:35am | #9

    Certainly a reasonable expectation. My apologies.

    I wouldn't and don't spec resilient channel. The fact is there is no single standard for its construction. Some is 20 gauge, some 25, some in between. Some are slotted for flex, some are solid, some have holes. The design of the channel is not standardized and likely not acoustically tested. Not something we can count on acoustically. Also according to the industry that manufactures it, resilient channel is likely (statistically) to have some of it will be installed incorrectly (short circuited).

    Again, there isn't a standard for strength, flexibility and consequently performance. Drywall Furring Channel, on the other hand, is specified by the Steel Stud Manufacturers Association, along with all other steel framing components. These channels are much more successfully deployed with resilient clips.

    This method of decoupling is effective if the steel can act like a spring. Since there's no manufacturing standard, the net result is that you have no idea if the resilient channel is too stiff (no spring) or too loose (no spring). 

    As mentioned, the Steel Stud Manufacturer's Asociation has a detailed spec requirement for Drywall Furring Channel, complete with load capacity, thickness, and dimensions. Resilient Channel can be made any way a local place cares to, with no performance or safety guidelines from the SSMA.

    Much better to use resilient sound clips and Drywall Furring Channel.

    1. DanH | Apr 09, 2011 09:46am | #10

      But isn't your DFC+clips just a special case of the RC, from a sound isolation point of view?  Essentially a "brand" of a generic category?

  9. TedWhite | Apr 09, 2011 09:53am | #11

    Hi Dan. It might initially appear that way, but they are, in fact, quite different.

    A clip and channel system woiuld have been extensively acoustically tested.

    The system incorporates a standardized steel component, the DFC

    The system is not at all likely to be short circuited

    The system provides much higher levels of isolation as dempnstrated by independent lab test

    The system can easily handle the weight of multiple drywall layers, common for high isolation environments.

    1. DanH | Apr 09, 2011 10:42am | #12

      So you'd tell a guy that he shouldn't use (or should "reconsider using") siding on his house?

  10. TedWhite | Apr 11, 2011 04:40pm | #13

    Just talking about soundproofing and the reliability / performance of products used.

    1. DanH | Apr 11, 2011 07:51pm | #14

      the reliability / performance of products used.

      And those aren't issues for siding, or plumbing products, or roofing???

  11. TedWhite | Apr 12, 2011 11:37am | #15

    Thanks Dan!

  12. Bowlinguy | Apr 20, 2011 12:41pm | #16

    Sound Proofing

    Your best bet in stopping the sound transfer is by using spray foam. The study that states otherwise was paid for by manufacturers of competing insulation products. It actually says it right on the first page. To me, that seems a little biased and I view it more as a commercial than a "study". The tight air seal of spray foam is what stops airflow, which is why it's used in sound studios, home theaters, and in industrial buildings to separate offices from louder machining areas. Look online for spray foam kits you can use yourself to keep costs down, and I am sure you will find testimonials from real people that have had great success in stopping sound transfer with foam.

  13. TedWhite | Apr 20, 2011 12:54pm | #17

    With all due respect that it

    With all due respect that is incorect. The National Research Council (NRC) is owned and operated by the Canadian government. It is the finest acoustics lab in North America, and possibly the world. The study referenced has been peer-reviewed for many years and is a standard research document cited constantly. The suppliers listed on page one most certainly did not pay to have tests falsified. They simply provided materials.

    Open and closed cell foams are too dense for acoustic purposes, and offer insufficient fiberous surface area to diminish the energy of a sound wave. Additionally foams can conduct a vibration and couple both sides of a wall (or a floor / ceiling).

    We are not looking to seal the stud cavity with foam, as there is no airflow from one side of the wall to the other. That is not the mechanism involved when we add absorption (insulation) to a cavity.

    1. User avater
      xxPaulCPxx | Apr 25, 2011 12:51pm | #18

      Ted, there was a question I had about sound and foam:

      I assume the foams used in the tests were the hard curing polyurathane closed cell foams.  But I wondered about the foams that don't cure hard, but cure flexible - the Window and Door sealing foams.  In addition to stopping air, I would think these would work to dampen sound, unlike the regular hard curing insulation foams.  

      Any tests on flexible foam?

      1. DanH | Apr 25, 2011 07:34pm | #20

        At least a soft foam wouldn't transmit sound as well as a rigid foam.  But it doesn't have enough included mass to effectively dampen the sound.  Actually dampening sound -- absorbing the sound energy and converting it to heat -- is fairly difficult, and most efforts are directed more at reflecting it.

  14. TedWhite | Apr 25, 2011 12:54pm | #19

    Foams in general have been looked at for a long time and are not spec'd by acoustical designers unless there's some thermal need to compromise the acoustic performance. Open and closed cell foams all fall into that do-not-use category for sound isolation.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Code Requirements for Fireplace Clearances

Avoid DIY disasters by following code-required clearances to combustibles, rules for hearth extensions, and trim-projection limits for elements above and beside the firebox opening.

Featured Video

A Modern California Home Wrapped in Rockwool Insulation for Energy Efficiency and Fire Resistance

The designer and builder of the 2018 Fine Homebuilding House detail why they chose mineral-wool batts and high-density boards for all of their insulation needs.

Related Stories

  • Timeless and Modern Bucket Sinks
  • Podcast 533: Missing-Middle Housing, Collateral Damage From Demo, and Midwest BS Symposium
  • Podcast 533: Member’s only Aftershow — Training for Tradework
  • Insulation Project Guide

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

BOOKS, DVDs, & MERCH

Shop the Store
  • Code Check Building 4th Edition
    Buy Now
  • 2022 Fine Homebuilding Archive
    Buy Now
  • Pretty Good House
    Buy Now
  • 2023 Tool Guide
    Buy Now
  • Shop the Store

Fine Homebuilding Magazine

  • Issue 313 - Feb/March 2023
    • Practical System for a Seismic Retrofit
    • Fine Homebuilding Issue #313 Online Highlights
    • Practical System for a Seismic Retrofit
  • Issue 312 - Dec 2022/Jan 2023
    • Tool Test: Cordless Tablesaws
    • Gray-Water System for a Sustainable Home
    • Insulate a Cape Roof to Avoid Ice Dams
  • Issue 311 - November 2022
    • 7 Steps to a Perfect Exterior Paint Job
    • Options for Smarter Home-Energy Tracking
    • The Fine Homebuilding Interview: James Metoyer
  • Issue 310 - October 2022
    • Choosing a Tile-Leveling System
    • Choosing Between HRVs and ERVs
    • Custom Built-in Cabinets Made Easy
  • Issue 309 - Aug/Sept 2022
    • 10 Steps to Install Crown Molding on Cabinets
    • How to Get Sturdy Walls Without OSB
    • Choosing the Right Construction Tape for the Job

Fine Homebuilding

Follow

  • twitter
  • facebook
  • instagram
  • pinterest

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences

Taunton Network

  • Green Building Advisor
  • Fine Woodworking
  • Fine Gardening
  • Threads
  • About
  • Contact
  • Advertise
  • Careers
  • Copyright
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2023 The Taunton Press, Inc. All rights reserved.

X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Account

  • Log In
  • Join

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Shop the Store

  • Books
  • DVDs
  • Taunton Workshops

More

  • FHB Ambassadors
  • Reader Projects
  • Podcast
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • twitter
  • facebook
  • instagram
  • pinterest

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in