# Pro's/Con's of wood and steel framing



## fr8train

I have absolutely NO experience with steel framing, so I thought I would ask you guys what you think.

What are some of the pro's and con's of both wood and steel framing?

Mike


----------



## muddermankc

Screw pops,screw pops,screw pops,screw pops,screw pops,screw pops,screw pops,screw pops, the wood is sh<t these days so it Will pop little circles of joy all up and down your beautiful finished walls.Yes on the screws,not a misprint. Any type of mud,any type of screw,any time of year,little circles of joy:thumbup:


----------



## sdrdrywall

metal is fast easy no crowning studs minimal tools studs are straight or not no bad lumber its light you can cut whole bundles of studs on the chop saw like i said quick and easy


----------



## A1rocker

weve found a lot of work steel framing and the best part is with experience anything can be done.Ive framed all different shapes of store fronts and soffits and the only limiting factor is knowledge and ideas.Radius framing is a breeze ,we use steel to frame arches even in wood framed structures.Needless to say i like metal the best although cost is sometimes prohibitive.


----------



## cazna

http://www.axxis.co.nz/index.php?site=1&pg=benefit


Steel framing has to be better, Our wood is sh!t, Pinus radiata, soft unstable rubbish, then we pump it full of chemicals to stop it rotting and getting eatin out by bugs.

Steel framing is lighter, stronger more stable, faster, wont rot, or move about like wood, much straighter. Its just starting to take off here and i will predict in the next ten years it will becomce more the standard.


----------



## A1rocker

cazna said:


> http://www.axxis.co.nz/index.php?site=1&pg=benefit
> 
> 
> Steel framing has to be better, Our wood is sh!t, Pinus radiata, soft unstable rubbish, then we pump it full of chemicals to stop it rotting and getting eatin out by bugs.
> 
> Steel framing is lighter, stronger more stable, faster, wont rot, or move about like wood, much straighter. Its just starting to take off here and i will predict in the next ten years it will becomce more the standard.


 the only problem with this is that it does rot,when we do remodel jobs we notice a lot of rust.Doesnt seem like a big deal but now a lot of our framing is structural and that should lead to more material testing.


----------



## Workaholic

Thermal bridging is more common with metal framing I believe.


----------



## cazna

A1rocker said:


> the only problem with this is that it does rot,when we do remodel jobs we notice a lot of rust.Doesnt seem like a big deal but now a lot of our framing is structural and that should lead to more material testing.


Thats Interesting, First time anyone has mentioned that, It must have sweated or has had moisture at it somehow for that to happen, What part of the framing was it, the lower framing closer to the floor????


----------



## A1rocker

always close to the floor and mostly when its over concrete.


----------



## sdrdrywall

the best way to prevent this is to lay the 5 inch wide 1/4 inch thick foam under your track so theres no metal to concrete contact


----------



## cazna

A1rocker said:


> always close to the floor and mostly when its over concrete.


Is it on the concrete itself?? We have to put DPC down first then the framing, DPC = Damp Proof Course, Melthoid, A paper tape mixed with tar type product that stops rising damp to prevent wood from rotting and damp getting to the steel, I would think the salts and lime and damp would be perfect for rusting even galved steel without the DPC.


----------



## fr8train

What is the cost comparison between wood and steel framing? I haven't seen steel studs for sale around here.


----------



## cazna

fr8train said:


> What is the cost comparison between wood and steel framing? I haven't seen steel studs for sale around here.


Here in NZ its the same cost, sometimes a little cheaper for steel, How does it compare in other areas???


----------



## sdrdrywall

steel is alittle more expensive and than im hearing a 20% increase on all steel products


----------



## 2buckcanuck

steel is great in basements,wood you half to lay it down to frame it .If there is a ton of junk in the way (furniture etc) you only need enough room to lay the track down with steel .You can can combine the two also,use steel track to replace the bottom and top plates ,but use wood for studs .
and for a safety tip,wood gives slivers,while steel can slice your hands open


----------



## joepro0000

Metal framing is the best. We have framed hundreds of tenant build outs in south Florida. We have done complicated store-fronts with heavy gauge metal, complex radius, exotic drywall ceilings, and much more. There is so many thinks you can do with metal thats so much faster vs wood. The older metal studs they used to yous years back are none for rotting out with rust. I seem some in condo renos. where I can just slap the stud with a hammer and it would crumple. Nowadays, the metal studs are made in galvinized metal to prevent problems like this. 25 gauge studs are cheaper than 2x4's and 20 gauge studs can be the same or little more, depending where and how much quantity you buy. I like to keep atleast 20 bundles of track in my house, because Im always needing more on the jobs.


----------



## fr8train

Other than the different thickness between 20 and 25 ga. Is there any other differences in their use? I.e. 20 ga for load bearing and 25 for non-load bearing walls, etc.

As I said before I have absolutely no experience with them, this is more out of curiosity.


----------



## Bill from Indy

fr8train said:


> Other than the different thickness between 20 and 25 ga. Is there any other differences in their use? I.e. 20 ga for load bearing and 25 for non-load bearing walls, etc.
> 
> As I said before I have absolutely no experience with them, this is more out of curiosity.


Neither will work for load bearing..an architect will have to specify what has to be used for load bearing, but usually it is at least 16ga


----------



## joepro0000

Bill from Indy said:


> Neither will work for load bearing..an architect will have to specify what has to be used for load bearing, but usually it is at least 16ga


sometimes 18 ga too, but most archs play it safe and go for 16 ga. Had some call out 14 ga, overkill IMO for a store-front. We used 14 ga - 12" studs!


----------



## A1rocker

we do a ton of load bearing structural framing and although the architect calls out the gauges it usually comes down to the manufacturers "shop drawings" to specify. If its only in the architectural section and not the structural drawings the shops arte what we go by.


----------



## evolve991

Another benefit of metal framing is the ability to move a stud if you need to as opposed to blasting a wood stud apart and trying to toenail the remains to the plate.


----------



## Mudshark

Seems nobody mentioned one of the more important aspects of metal framing - It doesnt burn like wood! Works great in circumstances where fireproofing would be needed over wood studs. i.e. you can frame a garage in withould sheething and fireproofing on the inside.

What I like the most is it doesnt warp like much of our wood studs.


----------



## gazman

Over the last 5 years (not including this year it has been realy quiet) I have drywalled over 200 steel frames. When we first started doing them we hated them. But now it is the other way around. We hate timber, you have to deal with it moister content, it warps and twists. a stud may be straight in the morning but later in the day when the sun hits it it starts to walk. We dont frame just rock and tape. The houses that we do are all steel including the trusses and these are battened at 450mm centres. Here are some FAQs from the prefab frame manufacturer. I realise that they are pushing there own wheelbarrow but they do make some sense.
http://www.steelframesolutions.com.au/faqs.html


----------



## chris

same feelings. wood sucks.:yes:


----------



## smisner50s

the first building wood framing steel trusses...second buildind all steel 14.16.18.20.ga..third building masony dock plank floors and 20ga framing insidegot lots of steel under my belt..my father and I company built them all.and still building them


----------



## Zendik

Mudshark said:


> Seems nobody mentioned one of the more important aspects of metal framing - It doesnt burn like wood! Works great in circumstances where fireproofing would be needed over wood studs. i.e. you can frame a garage in withould sheething and fireproofing on the inside.
> 
> What I like the most is it doesnt warp like much of our wood studs.


Steel fails at a certain temp. which is why we have fire protection in commercial buildings. A wood beam will burn on the outside while it's structural integrity will remain.


----------



## TonyM

I'd use wood every time. Metal clanks and the walls have less strength. Then again, I wouldn't have plastic or metal windows and doors either.


----------



## moore

TonyM said:


> I'd use wood every time. Metal clanks and the walls have less strength. Then again, I wouldn't have plastic or metal windows and doors either.


With all the rain and moister you lads have over there you don't like metal or plastic?? ....go figure:blink: If I had my way wood framing would be outlawed ..:whistling2:


----------



## Mudshark

*Steel stud*

Steel stud keeps drywallers working. Out here at least, many of the boarders also do steel stud. Carpenters are not brought in for steel stud work. Once you have worked with it you realize how nice it is to assemble.


----------



## SlimPickins

joepro0000 said:


> I like to keep atleast 20 bundles of track in my house, because Im always needing more on the jobs.


You must have a lot of extra space


----------



## Bill from Indy

SlimPickins said:


> You must have a lot of extra space


probably why the work limo gets parked outside:yes:

just messin with ya joe


----------



## joepro0000

lol...

I keep a stack of all types of metal, so when I need a few more, I'd rather grab them in the backyard and be at work at 7 than drive to the supplier and waste 2-3 hours. Remember, there is alot of traffic here in Miami, espeically driving into Miami!


----------



## joepro0000

BTW - Metal stud walls are not flemsy. If you know how to braced them you can stiff up a wall real strong!


----------



## Ted White

All things being equal, a 25 ga steel stud wall will be more soundproof than the same wall with wood studs


----------



## SlimPickins

Ted White said:


> All things being equal, a 25 ga steel stud wall will be more soundproof than the same wall with wood studs


I can start to guess at why, but I would be pleased to hear an explanation from an expert


----------



## Ted White

It's all about flex. The 25 ga steel flexes more than 2x4 wood, and therefore stops sound better. Similarly, a wall framed 24" OC will isolate more than a wall framed 16" OC.


----------



## SlimPickins

Ted White said:


> It's all about flex. The 25 ga steel flexes more than 2x4 wood, and therefore stops sound better. Similarly, a wall framed 24" OC will isolate more than a wall framed 16" OC.


I thought it had something to do with thinner material transmitting less vibrational frequencies. 

I just this moment started thinking about the two...steel is associated with higher pitched sounds (when you cut it, when you bang it, etc.) and wood transmits lower frequencies (dull thunks). It's those lower sounds that really travel through walls, right? Or am I being a ding-dong knuckle chomper?


----------



## gazman

If you want less noise transfer you can always stager your steel studs. NO TRANSFER.


----------



## Ted White

Slim. No worries with the frequencies. Guzman staggered studs still conduct through the top and bottom plate


----------



## SlimPickins

Ted White said:


> Gazman staggered studs still conduct through the top and bottom plate


How about a double steel wall, separated by a 2" gap with batt insulation on one inside and spray foam insulation on the other, then 5/8" sheetrock on one face, and double 5/8" on the other with a layer of Green Glue sandwiched in between?:jester:


Seriously though, a neighbor wants a sound reduction assembly in his basement. Are 2 layers of 5/8" (on the lid) with the specified amount of Green Glue going to make a very noticeable difference without added insulation? (He doesn't want to insulate because the joist bays are absolutely loaded with wires, etc.)


----------



## Ted White

Slim, that double wall you proposed would rock if you removed the foam. Stick with cheap fiberglass only for soundproofing.

For that ceiling, I assume he's hearing people above walking around? Footfall noise? http://www.soundproofingcompany.com/sp-solutions/soundproofing-ceilings/

Leaving out the insulation isn't the end of the world, certainly. To really arrest footfall noise (as compared to simple airborne nose) you have to take a multi-disciplinary approach. See Solution #5 in that article, for example. Simply adding another layer of drywall will help, but may not satisfy.


----------



## chris

SlimPickins said:


> How about a double steel wall, separated by a 2" gap with batt insulation on one inside and spray foam insulation on the other, then 5/8" sheetrock on one face, and double 5/8" on the other with a layer of Green Glue sandwiched in between?:jester:
> 
> 
> Seriously though, a neighbor wants a sound reduction assembly in his basement. Are 2 layers of 5/8" (on the lid) with the specified amount of Green Glue going to make a very noticeable difference without added insulation? (He doesn't want to insulate because the joist bays are absolutely loaded with wires, etc.)


 QuietRock:yesr RC


----------



## Ted White

Chris, RC is a very problematic product. For many reasons.

Why would anyone want to spend all that money on an exotic boutique drywall?


----------



## chris

Ted White said:


> Chris, RC is a very problematic product. For many reasons.
> 
> Why would anyone want to spend all that money on an exotic boutique drywall?


 QuietRock or RC IMO best solution for sound traveling thru floor to basement. Problems only occur with a halfass install


----------



## Ted White

The data doesn't support your opinion Chris. That's the value of independent data. You can filter through opinion and guesstimates and drill down to the answer. 

Pre-damped drywall is rediculously overpriced and underweight. You can create a field installed system that performs better for much less.

Resilient channel is the #1 soundproofing product involved in ongoing lawsuits. Google it if you're curious. If you're going to decouple (what RC is attempting to do) clips and channels are far superior. Virtually impossible to short circuit and provide much higher isolation.


----------



## SlimPickins

Ted White said:


> The data doesn't support your opinion Chris. That's the value of independent data. You can filter through opinion and guesstimates and drill down to the answer.
> 
> Pre-damped drywall is rediculously overpriced and underweight. You can create a field installed system that performs better for much less.
> 
> Resilient channel is the #1 soundproofing product involved in ongoing lawsuits. Google it if you're curious. If you're going to decouple (what RC is attempting to do) clips and channels are far superior. Virtually impossible to short circuit and provide much higher isolation.


When working for a designer I spec'd out a clip system that turned out to be the first application of its kind in Montana....it was amazingly effective.


----------



## Ted White

That's interesting Slim. Wouldn't mind hearing more details on that. Also, for ceiling noise, I'd recommend using the much less expensive one-piece clips (no rubber) and locally purchased 7/8" Drywall Furring Channel. No need to spend the $ on the more expensive 2-piece clips with rubber.

Using standard 5/8" drywall with a field-application of damping material is formidable.


----------



## chris

Ted White said:


> The data doesn't support your opinion Chris. That's the value of independent data. You can filter through opinion and guesstimates and drill down to the answer.
> 
> Pre-damped drywall is rediculously overpriced and underweight. You can create a field installed system that performs better for much less.
> 
> Resilient channel is the #1 soundproofing product involved in ongoing lawsuits. Google it if you're curious. If you're going to decouple (what RC is attempting to do) clips and channels are far superior. Virtually impossible to short circuit and provide much higher isolation.


 Just given my input on things I have done in past that work,just a drywaller. QuietRock is overpriced but is definitly not underweight. RC is a bit cheesy but works very well in sound isolation. Havnt used clips so dont know how they work. Just giving opinion on things that I have done and work. What data are you talkin about?


----------



## Ted White

I appreciate and respect your field perspective, Chris. 

The boutique drywall solution is most certainly underweight. You would field assemble a much heavier partition with standard 5/8” drywall, and field damping. Higher performance at a much lower cost. Keep in mind that we’re desperate to increase the mass of any partition if we want to soundproof it.

Resilient channel has no spec. When a steel stud is built, there are guidelines for all aspects of the stud. The thickness, rolled edge radius, galvanized coating thickness, etc. All specified by the Steel Stud Manufacturer’s Association (SSMA). They have tested steel materials for load and fatigue. There is no spec whatsoever for Resilient Channel, and anyone that bends steel is free to make up whatever untested RC design they’d like. Not many people would be comfortable with RC holding up much more than a sheet of ½” drywall overhead. The fact is that Resilient Channel does not work well, even in perfect installations.

In contrast, the 7/8” Drywall Furring Channel is indeed spec’d by the SSMA. We know what weight it will hold.

The tests I’m referring to are conducted by various NVLAP certified acoustic labs. Independent and objective.


----------



## chris

Ted White said:


> I appreciate and respect your field perspective, Chris.
> 
> The boutique drywall solution is most certainly underweight. You would field assemble a much heavier partition with standard 5/8” drywall, and field damping. Higher performance at a much lower cost. Keep in mind that we’re desperate to increase the mass of any partition if we want to soundproof it.
> 
> Resilient channel has no spec. When a steel stud is built, there are guidelines for all aspects of the stud. The thickness, rolled edge radius, galvanized coating thickness, etc. All specified by the Steel Stud Manufacturer’s Association (SSMA). They have tested steel materials for load and fatigue. There is no spec whatsoever for Resilient Channel, and anyone that bends steel is free to make up whatever untested RC design they’d like. Not many people would be comfortable with RC holding up much more than a sheet of ½” drywall overhead. The fact is that Resilient Channel does not work well, even in perfect installations.
> 
> In contrast, the 7/8” Drywall Furring Channel is indeed spec’d by the SSMA. We know what weight it will hold.
> 
> The tests I’m referring to are conducted by various NVLAP certified acoustic labs. Independent and objective.


 yes thickness of wall or ceiling helps with sound transfer but seperation matters most,especially in basement. I just hung QR on a job and that stuff was heavy,it had durock on back, great stuff to cut(not) .


----------



## Ted White

It's not the thickness so much as it is the mass. Mass is much more significant than cavity depth. You will build a more sound isolated partition with the added mass that comes from standard 5/8" drywall sandwiches.


----------



## chris

QuietRock claims there product is equivalent to 6 layers of drywall. Find it hard to believe. I will have to look into the furring strips you refer to. I find problems with RC take place during install, underqualified installers,usually an out of work hanger or framer puttin it up


----------



## Ted White

They used to say 1=8. Now it's 1=6. I'm not aware of anyone ever seeing data that supports such claims. Never even heard of a theory as to how they might substantiate that marketing sound bite. If anyone has such data I would be most interested in seeing it.

You would want a lower cost clip in addition to the Furring Channel. It's a spring system that you're assembling and installing drywall on


----------



## SlimPickins

Ted White said:


> That's interesting Slim. Wouldn't mind hearing more details on that. Also, for ceiling noise, I'd recommend using the much less expensive one-piece clips (no rubber) and locally purchased 7/8" Drywall Furring Channel. No need to spend the $ on the more expensive 2-piece clips with rubber.
> 
> Using standard 5/8" drywall with a field-application of damping material is formidable.


Ted, this was back in '96, and at the time no one in our area had heard of clips with rubber. We had a wealthy client who wanted a caretaker apartment added above their soon to be remodeled residence. While researching specs on RC I came across a clip system, and suggested it to the designer. We were a little disappointed with the amount of space required (there were some walls in a stairwell that gave us clearance issues). I think final buildout was 2-1/8 inches, 1-1/2 for clip mount and channel, and then the layer of 5/8. That's a lot of space. However, with the spray foam between floors (not my spec) and the clip/channel, a person could go upstairs and jump around and you _might_ hear it if you held your breath. It's a shame that the lovely folks remodeling never got to move in, they pased away in a canoeing accident a month before completion.


----------



## Ted White

Slim, interesting, indeed. Keep in mind that while clips with rubber (2-piece clips) have a role in soundproofing, the rubber isn't needed if there are no subwoofers, etc. Plain old neighbor noise, footfall noise, etc is treated with the less expensive "1-piece" clips with no rubber. They're 1/2 the cost.


----------



## SlimPickins

Ted White said:


> Slim, that double wall you proposed would rock if you removed the foam. Stick with cheap fiberglass only for soundproofing.
> 
> For that ceiling, I assume he's hearing people above walking around? Footfall noise? http://www.soundproofingcompany.com/sp-solutions/soundproofing-ceilings/
> 
> Leaving out the insulation isn't the end of the world, certainly. To really arrest footfall noise (as compared to simple airborne nose) you have to take a multi-disciplinary approach. See Solution #5 in that article, for example. Simply adding another layer of drywall will help, but may not satisfy.


Well Ted, after using green glue and a second layer of 5/8 in the basement referred to above, I must say I'm disappointed. The homeowner went ahead and installed batt insulation, but the footfall noise as well as just about everything else is still very audible. If I had to be honest, I'd say that it was definitely not worth the extra $1000. I've been called to do some soundproofing in some condos where the homeowners are complaining of noise...I'm going to refer to this link above when putting together scenarios and pricing.


----------



## Ted White

Hey Slim,

A few suggestions:

Make sure the glue has been able to dry 30 days. Wet glue does nothing.

I suspect the sound is simply sneaking (flanking) around the ceiling in some fashion. Examples:

Through the walls.
Through ceiling can lights.
Through ventilation.

You can install a ceiling from NASA, but if these flanking paths remain, you will never be satisfied. Only some of the sound energy you're hearing is coming through any given wall or ceiling. 

Also, as per the article I linked, adding a single sheet of drywall directly to the old drywall is the least effective method to stop footfall noise, for all of the reasons outlined in the article.


----------



## Mudshark

Ted, I am looking at the sound clips and thinking of applying it to existing home. Could the clips not be applied to the ceiling joists through the existing 5/8 drywall with longer screws instead of removing the drywall?


----------



## Ted White

Mudshark, we want to avoid that small air cavity that would be created if clips and channel were used over the existing drywall. We want to avoid the Triple Leaf Effect. http://www.soundproofingcompany.com...e-of-air-cavity-depth-the-triple-leaf-effect/

In general, we only want one air cavity in a partition. Therefore clips and channels must be installed over bare joists or studs.


----------



## Mudshark

Thanks Ted - I was afraid of that - looking for an easy fix I guess.


----------



## Ted White

Per Slims post above you can see there are a lot of variables. The quick fix is easier with pure airborne sound, however ceiling noise from footfall is an entirely different animal.


----------



## SlimPickins

Which leads us to another question:


What about sound board over existing with a 5/8"/Green Glue lamination?

How much sound transmission could be passing through above ceiling space (insulated truss system with a party wall)?


----------



## Ted White

A reasonable question, however the soundboard has little mass, and we want the mass. And in the customer situation you described, the addition of anything to that ceiling would not address the flanking around the ceiling.


----------



## SlimPickins

Ted White said:


> A reasonable question, however the soundboard has little mass, and we want the mass. And in the customer situation you described, the addition of anything to that ceiling would not address the flanking around the ceiling.


Actually, I'm inquiring for another application. Condos (party wall), with resident complaints of sound transmission. I'd like to go over the existing board, due to the fact that the units are completely finished and carpeted, etc. 

These guys claim this product will work for lamination over existing....thoughts?

http://www.rsic1clips.com/rsic_clips/rsic-1-r.htm


----------



## Ted White

The small air cavity created with an installation in that fashion is a distinct liability. It creates a classic Triple Leaf.

Remove the existing ceiling drywall and now you are getting somewhere


----------



## SlimPickins

Ted White said:


> The small air cavity created with an installation in that fashion is a distinct liability. It creates a classic Triple Leaf.
> 
> Remove the existing ceiling drywall and now you are getting somewhere


That's what I thought, thank you sir.


----------



## Ted White

Looking at that article on ceilings, Solution #4 or #5 is the most definitive because the vibration is being treated at the source, which is the subfloor above. Once that vibration is in the subfloor it will travel everwhere through the very conductive joists and subflooring. If we can start arresting the vibration at the subfloor level, we have a much higher level of isolation. 

Keep in mind that vibration racing through the framing overhead will make it to the side walls holding up this vibrating joist system. So now it's in the walls. If we cannot reduce the vibration at the subfloor level, we're going to live with some amount of noise.


----------



## SlimPickins

Ted White said:


> Looking at that article on ceilings, Solution #4 or #5 is the most definitive because the vibration is being treated at the source, which is the subfloor above. Once that vibration is in the subfloor it will travel everwhere through the very conductive joists and subflooring. If we can start arresting the vibration at the subfloor level, we have a much higher level of isolation.
> 
> Keep in mind that vibration racing through the framing overhead will make it to the side walls holding up this vibrating joist system. So now it's in the walls. If we cannot reduce the vibration at the subfloor level, we're going to live with some amount of noise.


I imagined that we were encountering substantial flanking noise, and realized that the available solution would not be perfect.

Side note: I love working with your product (Green Glue). Having recently done an airtight drywall assembly using a Tremco product, I realized just how much I prefer Green Glue. I even like the smell Mostly, water clean-up is the best feature when working with it, although........I'd like to see a foil seal instead of the plastic that needs to be cut before installation.

I'm browsing your website in between reading posts here....interesting information, and I like reading about how you got your start.

Would you recommend using your product in an airtight assembly scenario? Cost compared to Tremco Acoustical sealant is quite comparable.


----------



## Ted White

Thanks for the kind words, Slim.

The Tremco is a sealant, whereas the Green Glue is a damping compound. Green Glue makes a lousy sealant and Sealant makes a lousy damping compound.


----------



## SlimPickins

ted white said:


> thanks for the kind words, slim.
> 
> The tremco is a sealant, whereas the green glue is a damping compound. Green glue makes a lousy sealant and sealant makes a lousy damping compound.


bummer


----------



## guijarrero

Ted White said:


> All things being equal, a 25 ga steel stud wall will be more soundproof than the same wall with wood studs


soundproof depends on mass or quantity of matter (weight) thats why cellulose improves it.



SlimPickins said:


> I can start to guess at why, but I would be pleased to hear an explanation from an expert


asked an arch




SlimPickins said:


> How about a double steel wall, separated by a 2" gap with batt insulation on one inside and spray foam insulation on the other, then 5/8" sheetrock on one face, and double 5/8" on the other with a layer of Green Glue sandwiched in between?:jester:


more expensive?


----------



## Ted White

guijarrero said:


> soundproof depends on mass or quantity of matter (weight) thats why cellulose improves it.


Mass is the # factor in sound isolating design, but not in a partition cavity. Studies done by many, not the least of which is the NRC in Canada, show that a lower density insulation is preferred, especially for low frequency (bass) isolation. 

This is one of those times when the cheapest is also your best option, but only from a soundproofing standpoint. Mineral wool or a low-density cellulose application is fine lso.


----------



## guijarrero

Ted White said:


> Slim, that double wall you proposed would rock if you removed the foam. Stick with cheap fiberglass only for soundproofing.
> 
> For that ceiling, I assume he's hearing people above walking around? Footfall noise? http://www.soundproofingcompany.com/sp-solutions/soundproofing-ceilings/
> 
> Leaving out the insulation isn't the end of the world, certainly. To really arrest footfall noise (as compared to simple airborne nose) you have to take a multi-disciplinary approach. See Solution #5 in that article, for example. Simply adding another layer of drywall will help, but may not satisfy.












It looks expensive, forgive my soundprof not-so-big-experience. However, I heard about putting a fiberglass bed above existing subfloor and then, another wooden big sheet.. and seeing your picture, not being an expert remember, I wonder why hang if you can add above? Please tell me your oppinion.

In the other hand,either talking about RC or 
furring chanell we are talking about stoping vibrations, not adding a weighting barrier.

"Regarding sound generated inside the building, there are two principal types of transmission. Firstly, airborne sound travels through walls or floor and ceiling assemblies (...)The second type of interior sound is called Impact Insulation Class (IIC) transmission. This effect arises not from airborn transmission, but rather from transmission of sound through the building itself." http://en.wikipedia.org/wiki/Noise_mitigation


----------

