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wwkayaker 09-13-2012 05:10 PM

I have read a lot of posts on this site about attempts to soundproof a basement and many seem contradictory and it is confusing. Can anybody who has been successful/unsuccessful in their attempts to deaden the sounds between the basement and mainfloor of their house share what they have learned.

I have a drop ceiling in my basement. The basement is a self contained apartment. A lot of noise travels between the upstairs and downstairs. I would like to reduce the noise as much as possible.

I have read about roxul, greenglue, doubling up on 5/8 drywall, regular insulation, and noise dampening ceiling tiles. I can't go to hanging drywall with clips due to time and money. i was thinking about new acoustic ceiling tiles if they will say what they company claims with roxul between the joists. I even might pull off double 5/8 drywall sandwiched with a dampening material between the joists but green glue is not cheap.

weekendwarrior9 09-13-2012 05:56 PM

do you have access to the floor joists? can you remove the drop ceiling? Is the drop ceiling a metal hanging frame, or is it built-in with 2x material?

If it's a metal hanging ceiling, I'd remove it, make sure the floor joists are insulated (as much for the sound as for heat), and cover in drywall. Then I'd add strips of 1x material along the joists and install another layer of drywall leaving an air pocket between the layers. I find that works better than straight doubling of drywall.

Sound will still come through, and if it's hardwood floors above, significant amounts of certain types of sound will still come though (like sharp noises like heels walking on floor).

FWIW I've not done this between basement and floors before, but I've used it between walls. There I had the luxury of adding the second stripped layer of dry on both sides of the wall, here you can't do that so I can't say for certain how well it's going to work.

allthumbsdiy 09-13-2012 08:16 PM

The very first thing I would do is to use expansion foam (probably should use fire blocking foams) on all those vertical pipes (water, dwv, etc.)

notmrjohn 09-13-2012 09:58 PM

A suspended soft back fiber panel ceiling without any solid connection to floor or framing above, (metal wall frame, wire suspended interior frame [wires hung thru rubber grommeted standoffs, to go extreme]) with sound dampening insulation supported above and not touching ceiling. Glass fiber insulation not a good sound barrier, recycled treated cotton batts pretty good. Minimum of sound reflecting hard surfaces in basement, carpets, upholstered furniture, fabric wall hangings etc instead.
Back when I was with world famous band, The Bensley Trio Two, we covered interior walls of uninsulated garage recording studio with glued on oddly shaped styrofoam packing inserts. More we glued up, less neighbors complained. You could do a whole lot of online shopping and glue packing up between joists. Well, you could. but odd shapes, irregular surfaces block more sound, Batts thinner than joist could be allowed to sag and rise between joists, using strong string or cord to suspend.
Real life actual experience, not basement but 1st floor room, with suspended ceiling under cotton batts under wood board floor under foam underlayment under laminate floor( which really clicks and clacks from heels), covered first floor vinyl tile with carpet tiles. Noticable lowering of sounds from above.

oodssoo 09-14-2012 10:08 AM


You should look at how much money you have to spend first.

Acoustic ceiling tiles will certainly work to a certain degree. And I think having that and studio sound-deafening materials would be a great combo.

Doubling on the drywall is too much work and the associated cost does not justify to me for this project.

Batt insulation is designed to insulate against "temperature transfer" rather than noise. So, for me, I'd skip that idea altogether.

Hope this helps some and keep us updated about your progress!

Ps. Curious to see some photos.

notmrjohn 09-14-2012 01:12 PM

oods, you're right about batt insulation not being designed as sound insulation. Glass fiber especially bad at it. Cotton batts are big step up, they may not have been designed for it, is just an added benefit, and way less expensive than most sound designed insulation of similar capabilities. ( 'cept maybe those styro packing pieces) whoopin out my handy Sound Transmission Classification chart, which is part of a very unhandy thick volume of construction charts and specs, and without going into STC numbers and what they relate to,we find; Uninsulated 1/2 drywall-Loud speech can be understood fairly well. Add 3 1/2 " glass fiber-Loud speech audible, right on the brink of what STC considers privacy. Doubling drywall just barely pushes it over brink. Replace glass with cotton and we jump way up to- Very loud sounds, musical instruments, stereos, faintly heard. Loose fill cotton even higher, but my chart is for walls, and loose fill under a floor not so easy to fill. And walls don't get walked on much. Besides i don't know if i trust this chart all that much, nothing at all about molded styrofoam packing pieces glued on a wall.

bbo 09-14-2012 01:36 PM

here is what i did so far for one section in my basement 9 home office i work out of)

1) remove drop ceiling with acoustic tile
2) i used the denim batts between my joists
3) then resilient channel to help decouple drywall from joists
4) then a layer of 5/8 drywall
then green glue noise proofing compound
then another layer of 5/8 drywall
then seal edges around perimeter with green glue sealant.

its really helped with the sounds like TV and talking upstairs and also the sounds of the kids running above.

i know there's more i can do, but budget really dictates cost. and FWIW, the green glue costs more than the drywall did for the same area. example, i could seal the can lights ( they themselves were already ic and airtight) to the ceiling, i could also drywall the exterior walls and decouple them with resilient channel. i could rework the ducting as well since part of this room has the ducting overhead which allows sound leaks. but it always back to cost vs. benefit.

there are many sites out there with specs for different soundproofing methods. my suggestion is to do a lot of research and don't look for any one product to be a cure all. you really need both mass and dead airspace with something to absorb sound to be successful. and also be realistic with your expectations based on what you decide to do.

wwkayaker 09-15-2012 11:53 PM

The advice is all very helpful. Thanks.

I have been looking at options and there certainly is a wide range in cost. I have noticed to that a lot of sound seems to come through the duct work and one of the telescopic posts in the basement seems to be a favorite drum for the tenant in the basement. I heard about a soundproofing silicone for ducts but I can't find info on it. The telescopic post likely needs to be framed in to get rid of the noise is transfers.

wwkayaker 09-15-2012 11:59 PM

bbo, I looked at green glue and I was going to do a cost estimation. Just from the price of around 12$ per tube and the requirement of 3 tubes per 4x8 sheet of drywall, it would be worth more than the drywall for sure. For a double ply of drywall and glue, it is about $50-55 for 32 square feet. Then the work involved is not going to be quick and easy.

I am trying to be realistic and from what I have read, some noise is going to come through almost regardless of what is done by the average homeowner.

FWIW, I have been reading about white noise machines and there potential to alleviate some noise pollution.

Ted White 09-16-2012 07:39 AM

To clarify a few points:

Cotton fiber insulation is ecological, however lab data shows us that in fact simple fiberglass works best. The notion the cotton works better comes from those that sell it. This is NOT an area to spend a lt of time and consideration on.

Damping compounds should be used at the rate of two tubes per sheet, not three. Additionally, if the soundproofing needs are low (not a home theater), then you could look at 1 tube per sheet. Three tubes = a dealer looking to simply make more $.

Ceiling tiles are designed to reduce the echo for those working below. They do not sound isolate as they lack bass and are not sealed. Some guys have cur squares of drywall and laid on top of the existing tiles after reinforcing the grid support wires. This isnít great but sometimes all that can be done.

notmrjohn 09-16-2012 01:48 PM

Ted, I'm not gonna argue with you, i am not a soundproofing guy. But every bit of data I've seen and personal experience, using my highly accurate and meticulously calibrated ear drum, states that cellulose (cotton) and even rock wool are better sound absorbers than glass fiber. Granted, one should always consider the source of data and results. Data provided and research funded by those who have a financial stake are always suspect, from manufacturers spinning glass, clerks selling tubes, to people ripping up old jeans. Hard solid glass fibers actually transmit sound, probably not enuff for the average ear to detect but the cumulative effect is there. I would be interested in seeing the independant lab data that "shows us that in fact simple fiberglass works best" or at least the source. I/m familiar with the Pink Panther funded thermal study at Baylor University, just down the road from OC's glass fiber factory, and where an OC VP is on advisory board. You'd never guess what kind of thermal insulation the research showed is best and who has a remarkable propritory process that makes it even better.
"This is NOT an area to spend a lt of time and consideration on." Agreed, with an emphasis on a lot of time or money. But if one is going to insulate any way, considering possible price difference, a "soft, fluffy" material such as cellulose, is going to do a better job at absorbing sound than a hard stiff material such as glass.

What ever insulation is used should be as isolated from direct contact floor above, and ceiling below. A suspended ceiling is an easy way to do that. Doubled , sealed, isolated, dampened drywall is much better but more expensive and time consuming to install for DIYer. Gotta have a ceiling anyway, suspended acoustic, as the fellow said, "Couldn't hoit." If your trying to cut down on noise from above, why not cut down on echo from below, some of which may have been transmitted from above.

And I just realized I may have been laboring under a misapprehension and jumping to a foregone conclussion. " favorite drum" of tenant below. I thought we were stopping down ward bound sound. Genuine acoustic ceiling tile will help some against rising tide of sound. Won't do much against musical stylings of pole drumming artist. If you box in pole, which would look nicer anyway, don't bulid hollow box, that will just add bass drum. isolate box from pole and ceiling, (isolate, or pad pole from ceiling) put sound absorbing material in box. ( Bound to be some sort of insulation or something that would work, folks sell all sorts of stuff and say they have the data to prove it works. Or stuff box with old rags or bits of broken beer bottles.)

Duct work. Duct work and open floor registers are useful in catching foreign agents and creating sit-com plots. But perhaps you are not living in B movie serial or have Lucy Ricardo as tenant. Metal of duct itself transmits sound, there are dampening connectors that claim to stop that. Fiber duct board transmits less sound but is less durable. Hollow duct of course is sound tube, useful for calling for more speed from engine room, if you live in battle ship under torpedo attack. There are dampers, baffles and baffle chambers, which are claimed to cut down on noise transmission. They also cut down on air transmission and some create ait noise, a sort of white noise if you will.

White noise machine. I use a fan by the bed for that, white noise and cooling in one. Machines and " sounds of nature" recordings mask noise by creating more noise. In a register that is less annoying, and perhaps eventually unnoticable but ears and brain sense it even if you don't. Studies show that constant exposure to white noise can increase tension and anxiety. ( Those studies were not financed by white noise machine dealers.) Distant traffic and even airplane sounds can be white noise, conciously unnoticed but subconciously annoying. They aren't very effective against sudden sharp noises, such as pole drum solos duct work yodeling or laminate floor tap dancing.

Kayaker, I'd suggest you do things in stages as budget and time allow. Insulate under floor, I stand by my cellulose or rock wool batts, isolated suspended ceiling, both of those relativly easy to do and remove if you step up to double dampened ceiling and engineered true acoustical insulation and all kinds of other stuff they got. Boxing, insulating, and isolating Gene Krupa's pole, doing something about ducts, and softening interior surfaces of basement. Away back B4 they had dependable drywall, there was an interior, relativly soft, cellulose fiber wall board called Homasote, brand name that became generic. When sheetrock replaced the fiber board, folks noticed an increase in reflected sound. They bought Homesote, wrapped cloth around it and tacked it to the walls.Deadened sound, easily changable decor. Homasote, faced with plummiting sales, knew a good thing when they heard it. Homasote is now marketed as a sound "proofing" material, you've probably run across it in your research. Homasote has the data to back up their claims.

I've made enuff noise for now, a lot of it too, but mostly unimportant white noise, but I'm bored and don't have a pole to drum on. I'll leave you in peace for now, but warn you that i am easily bored. I'l lprobably be disturbing you again. However, I do pay my rent on time.

Ted White 09-16-2012 02:10 PM

Insulation lab data provided by the National Research Council of Canada. Finest acoustics lab in North America. Their study IR761 has a great deal of helpful data. We just want lower density fiber insulation. Could be cellulose, polyester, cotton, fiberglass, mineral wool. As a general rule, any similar-density insulation will work similarly, however the fiberglass technically has an edge in low frequency isolation performance. I'd say get whatever's cheapest, but know that you won't be buying better performance.

Don't compress the insulation, otherwise your low density insulation becomes high density and will better conduct a vibration.

The higher denser insulations are much better on the surface of a wall acting as absorbers.

Duckweather 09-16-2012 05:12 PM

The best sound deadening I ever used was between a shop that repaired chainsaws, and their office, was a layer of thick shag carpet on a wall, (your floor joists), with another wall not touching it, (your ceiling tiles). You couldn't hear a chainsaw running from the office. I think it absorbs the sound, not insulates it. Whatever it was, it worked, and that's all that counts.

oodssoo 09-16-2012 08:35 PM

One thing I could suggest... It works at our house...

You could have dedicated headsets for the individuals participating in the, say, visual and audio entertainment by way of a HDTV/Theatre-like Projection. The amount of money invested in this set up varies - of course. However, everyone can customize the volume and sound dynamics, all in the while in other adjacent areas of the house, no sound is heard or felt.

Just a thought.

asolutions 09-17-2012 11:13 AM

An easy way to soundproof your ceiling would be to replace/cover the existing drop tiles with sound blocking tiles/barrier.

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