Metal Studs?

Is there any reason why i couldnt use metal studs to build my project? I know they will probably cost more but with my slow ass building skills i wouldnt have to worry about wood rotting before i could get a roof on it.

http://www.buildingscience.com/resource ... ldings.pdf Read carefully the section on Moisture Balance, but read the entire document a few times til you completely understand what Joe is saying; Bottom line is, I don't recommend steel/gypsum construction in a highly insulated, sound proof studio UNLESS you have enough space to dedicate at least a FOOT of open air space between inner and outer wall frames, and a way to ventilate that space to inner, dehumidified and conditioned space when not using the studio. My own planned facility will have at least two FEET between inner and outer wall leaves, with full air circulation between them and dehumidification in addition to the HVAC system. If you use steel framing, you need to spray any cuts with zinc chromate primer before assembly. You also need to make sure all connections between concrete and steel stud frames have a thermal break - 2 layers of 30# building felt works, as do a few specifically intended products. You do NOT want the moisture in concrete (read the linked PDF about that) to be in contact with your steel framing. The more insulation (decent sound isolation) the more this is true. Have you posted plans for your construction anywhere yet, or is it not to that stage yet? Generalities can only take us so far, then it's time for specific details. IF you're planning a free-standing or add-on space, you might want to consider dry-stack block walls - easy for one person, stronger than mortared block, and (filled with sand) VERY good outer mass leaf. \ http://www.thenaturalhome.com/drystackblock.htm http://www.new-technologies.org/ECT/Civil/psk.htm Some things to think about... Steve

Thanks, I was just wondering about other options. I have the thread "studio Layout help" going but i was just looking for options. Metal seemed to be less weight and easier for one man to mess with as well as not having termites and other critters to deal with.

Right, and steel also has the advantage of "no knots" - I'm not saying it shouldn't be used, only pointing out some things to be careful of that could otherwise spoil your fun... Steve

that block thing looks kinda cool too.

Yeah; it's strong, it's masonry, it's massive, it's doable without help (if you know how to build a footing), and it's relatively fast (no mortar except for bedding the bottom course of blocks) - and the surface bonding cement adds to mass for better TL than mortared block, even when both are filled... Steve

my problem is i already have a slab poured.

Might not be a problem - what dimensions are the perimeter footings, rebar, steel, etc? It's possible your existing pour might be strong enough already... Steve

My slab is 18 x 24. i believe the footing is a foot deep and loaded with rebar and mesh. i have no doubt it is strong.

I finally found time to check your other thread; I think that, if you DIY and get help from friends you CAN enclose the space within your budget; but a couple of points - One, if you build NORMAL wall construction (stud frame, some kind of outer siding) it will NOT be easy to upgrade that outer leaf of mass when you get more $$ for the inside construction - so if possible, I would add at least one more layer of heavy plywood on your outer stud frame before hanging siding on it - that way, you'll have a fairly hefty outer mass in place. Two, you need to think in terms of two separate mass envelopes, as isolated from each other as possible, for best sound control. So the outer envelope will need to be one continuous un-broken high mass surface, including the roof or ceiling; if you do a vented roof, then you need to make the "box" tall enough so you will have room for an inner frame and ceiling material IN ADDITION TO the outer leaf - see the illustration below for what I mean. As to what to use to get this "mass envelope", your timing sucks nearly as much as mine :cry: - Thanks to the lovely "KATRINA", heavy plywood (like the 3/4" you'd need under your outer siding) will probably double in price in the next couple weeks (again) - for that reason, I'd not dismiss the (DRY sand filled) concrete block outer mass without first comparing material costs. One problem with the dry-stack method though - standard blocks are NOT 16" long, they're 15 5/8" long to allow for a 3/8" mortar joint - so dry stacking makes them come out uneven compared to standard building sizes, except in wall lengths of 13 feet (13.02 feet actual) 26 feet (26.04 feet actual) and 30 feet (29.95 feet actual) - in the case of your 18 x 24 foot slab, you would need to use partial blocks somewhere in each wall in order for your footings to be directly under the mass of the wall (assuming your footings are even strong enough for the weight - this type wall would weigh about 940 pounds per lineal foot (assuming 10 foot tall and sand-filled) Considering your (very) tight budget I think I'd go for a single stud frame with 2x6 studs on 24" centers, and sheath the outside first with 3/4" OSB, Tyvek and siding - this would give decent outer mass.If you go with 12' tall walls and a gable roof, you can vent the roof thoroughly and use double 5/8 gypsum on the bottoms of your roof trusses for a continuation of your walls' outer mass - then there would be room for an inner frame later for the inner ceiling and inner wall mass. Doing it this way would allow for a "pay as you go" approach that won't be "half-fast" when done, and still let you get the place weatherproof NOW... Steve

knightfly wrote:

Considering your (very) tight budget I think I'd go for a single stud frame with 2x6 studs on 24" centers, and sheath the outside first with 3/4" OSB, Tyvek and siding - this would give decent outer mass.

I am a little lost on the 2x6 studs. I was thinking of 2x6 top and bottom plate and then staggered 2x4 studs, thus allowing some separation between the inner and outer walls. I was also thinking of using 8x4 hardiboard as siding. that stuff is just super tough and paintable as well. I think the Katrina thing will probably slow my building down till the first of the year. Most of there evacuees are here and i expect since we sent just about every utility worker we have in there direction; then more than likely there building materials will come from our local Papermills, steel mills, lumber companies, etc.... I am in no major rush. I wanna do it but i am a tightwad with money so i can wait till the prices come back down. Who knows maybe by the 1st of the year i can save enough money to just do it all . If i stay on this board i may even be smart enough to do it right. :lol: thanks for the help.

I am a little lost on the 2x6 studs. I was thinking of 2x6 top and bottom plate and then staggered 2x4 studs That is one way you can do it; I don't know just how much isolation you will need, so my suggestion was part of a plan to do full 2x6 stud frames for your outer wall, then when "phase 2" happens do a second, isolated frame inside that and use 2 or 3 layers of 5/8 gypsum wallboard - the fully separate inner frame will improve TL by about 4 dB at low end, and about 10 dB at midrange. It's actually cheaper to frame entirely with 2x6 on 24" centers than to frame with staggered 2x4's, since they need to be twice as close together and 2x4's cost more than half what 2x6's cost. The Hardiboard thing - if you're talking about their LAP siding, bad idea. Each joint is a major leak area, as well as a thin spot in the mass envelope... Steve

i was talking about the 8x4 sheets of hardiboard like plywood but concrete.

Steve, a bit of Googling tells me that HardiBoard is a competitive product to WonderBoard (by Custom Building Products) and Durock (by USG Corporation). I'm nnot sure who makes it, or even that the spelling is correct, so I can't find a data sheet for it.

it is basically hardi plank siding but it is in sheets of 8x4 instead of strips. that durock looks very similar

This perhaps? We sell it at the store I work at. It's heavy and usually comes in 3x5 sheets.[/url]

Here's the data sheet for Hardibacker® by James Hardie. It comes in various sizes. "Hardiboard" is probably an unofficial nickname for the product -- perhaps confused by its competitive cousin, WonderBoard. --Keith :mrgreen: Edit 12/21/2005: Changed spec sheet link to USA version and corrected sizing information.

OK, better - the 3x5 sheets of these products (all about the same stuff) is sized for use around tubs as a tile underlayment instead of the "green board" version of gypsum, which isn't quite as moisture resistant as the duroc/hardy board stuff. Most manufacturers also make this in full 4x8 sheets. The mass is nearly double that of gypsum, but this also makes the stuff really painful to apply unless you're Hercules - weighs about 125 pounds per 4x8 sheet. I've not used this as part of a wall yet - I'd be a bit careful, since there would typically be only one layer so filling between sheets and getting a continuous mass might be tricky. Maybe use something like the concrete version of FixAll patch to fill in the cracks, dunno... The other downside - expense. Gypsum is 'way cheaper per square foot. Also, don't remember seeing if the cementitious board (generic term) is rated for direct application to frames, or if it's not strong enough to provide racking resistance. Also, you might have to fill the cracks between boards from the OUTSIDE; there should be a Tyvek liner between siding and studs, which would keep you from being able to fill cracks from the inside... Steve

knightfly wrote:

. . . don't remember seeing if the cementitious board (generic term) is rated for direct application to frames, or if it's not strong enough to provide racking resistance.

Excerpt from "Sheathing Alternatives to OSB and Plywood May Be Worth Considering", published by the National Association of Home Buliders:

Cementitious Board. Consisting of Portland cement reinforced with fiberglass mesh, this is typically used as a backboard for ceramic tile installations and has been used as exterior sheathing under a stucco cladding. Not structural in nature, buildings sheathed with cement board must have corner bracing. Producs include Durock by USG and WonderBoard by Custom Building Products.

Perhaps you'd consider Fiberboard, which according to the same article, which is structural and has "sound attenuation properties":

Fiberboard. Known commonly as blackboard, grayboard or buffaloboard, this is constructed of wood compressed with other materials and is used primarily for wall sheathing and floor underlayment. It can be made of recycled fiber, has a higher R-value than most wood-based sheathings, has sound attenuating properties and is less expensive than other wood-based sheathings. Products include Stedi-R and Stedi-R Structural from Georgia-Pacific, Buildrite Structural Sheathing by International Buildrite, Temple Fiber Brace by Temple Inland and Celotex Premium Insulating Sheathing by Knight-Celotex.

What do you think, Steve?

Nope; fiberboard, celotex, homosote, etc, all too low mass to be a good idea. Plywood would work better, and it's still not as heavy as gypsum. If you cant/don't wanna use corner bracing, for an outside wall structure I'd put up the heaviest plywood/OSB you can afford, put your favorite siding over it, and plan on a second inner frame with several layers of gypboard. If people are building from scratch, it's not practical to re-invent the wheel - if you stick with proven methods, and do them right, you'll get predictable results. When you start wanting to try compressed monkey-doo, fried marshmallow, straw bales, etc, you're pretty much on your own. No one here has (or can afford) the kind of lab environment and man-hours it takes to properly test odd-ball materials. I know we get into some pretty esoteric stuff at times, but the only time I consider that necessary is when someone is trying to "turn a sow's ear into a silk purse", so to speak; it can be very daunting (as most of us know) to convert an already existing space, one that was built with no intent or knowledge of sound isolation) into something that works. That's when it's usually necessary to get creative, NOT when you have the golden opportunity to build from scratch. Anyway, when trying to figure out what to use (new construction) it's really very simple - for outer layers, you need structural strength and moisture resistance. Find the thickest, heaviest material you can afford that meets those requirements, and hang it on your outside frame - follow the recommendations for gap spacing (you'll be sorry if you don't) for that specific material, then caulk those gaps for a flexible, airtight seal. Cover with whatever siding you decide on, preferably one that does NOT leave gaps (like hardi-plank or other "lap" sidings). This will be your outer leaf. For inner surfaces it's easier - in the US at least, gypsum is king. Period. Only exception I can think of is if you are a mason. People who envision wanting to hang stuff on their walls have good results putting a layer of MDF under the last layer of drywall. Put several layers on the inner frame, no seams coincident, either hire a pro drywaller who will LISTEN about decoupling or learn to do it yourself - this will tell you more about drywalling than you ever wanted to know, although even it is pretty light on sound construction; but you can get that here :? Soooo, any-hoo, for the 4704th time, use the heaviest cheap (or cheapest heavy) stuff you can find, seal it, leave an insulated air gap (larger is better, up to 3 feet if you can afford the space) and do it again. Rather than repeat ALL this again, please re-read the REFERENCE section - And when you're shopping for wall panels, try this - rest the panel on your foot, right where your toes curl up when you eat your favorite pizza; if it doesn't hurt, it's not HEAVY enough :lol: Steve

the reason i am talking about the hardiboard or durock is for the exterior of the building mounted straight to the studs. only thing going on top of the board would be paint. I have done this to buildings before and it looks great but will it work for a rock n roll band. Keep it coming though. :D its like online college courses for free :D :D

If hardiboard or durock are continuous (no cracks, or sealed cracks with equal mass) then one layer of that should be approximately equivalent to maybe 1-1/2 thicknesses of 5/8 gypsum. One problem is the joints; this is why two layers of gypsum per leaf is the practical MINIMUM - that way, joints can be overlapped (MUST BE) for a continuous mass. IF you can get this outer layer sealed well enough, then putting at least two layers of 5/8 wallboard (NOT celotex) on a separate frame so that the panels are at LEAST 8" apart, will give you fairly good isolation. Rocktavian, I know you're on a tight budget, but I still think you'll be better off weatherproofing your build using 2x4 stud frames - when you consider that staggered stud walls take twice as many studs ANYWAY, you're only saving about $40 or so by framing with 2x6 caps/plates and staggered 2x4 studs, and you'll be LOSING AT LEAST 8 dB of isolation at every frequency!! This is based on the fact that a 2x6 staggered stud wall gives 5.25" of air gap, while a double stud frame with studs 1" apart gives 8" air gap - using the exact same mass on each side, the diff between staggered 5.25" gap and separate framed 8" gap is 8 dB at 50 hZ, increasing to about 12 dB at 500 hZ and above. All that extra noise blocking for about $40 and a 3" loss of floor space all around - keep in mind that extra space, if NONE of it is usable for music, won't help you much... Steve

I am with ya on the 2x4's. Space is precious but i see your point.The hardi board joints are basically butted end to end. would caulking them really good be sufficient? the separate walls brings me some more questions but i will search first and see what i can find. Mainly concerned about whether the inner shell can be in contact in any way with the outer even if it is just a couple of metal strips to hold it in place. I only have have anchors set for one wall would i just ramset the inner walls? This question has got me stumped. I had planned on using a window unit A/C and building some insulated overlapping doors on hinges to cover this thing up when the red light is on. I have no idea how that would work with 2 walls, and if they cannot be in contact at all that pretty much shoots that plan out the window. Katrina's inflicting some serious impact on my wallet so i have nothing but time to figure out how i wanna do it. I couldnt afford to go pick the material up at $3.00 a gallon if they were giving it away. thanks and i will search to try and find answers to some of these questions on my own. I know you guys hate repeating yourself.

rocktavian wrote:

Mainly concerned about whether the inner shell can be in contact in any way with the outer even if it is just a couple of metal strips to hold it in place. I only have have anchors set for one wall would i just ramset the inner walls?

Metal strips, no. Resilient sway braces, yes. See this thread for more information on that.

This question has got me stumped. I had planned on using a window unit A/C and building some insulated overlapping doors on hinges to cover this thing up when the red light is on. I have no idea how that would work with 2 walls, and if they cannot be in contact at all that pretty much shoots that plan out the window.

See my project plan with regard to my air conditioning, ventilation, and silencers, starting here. It isn't cheap, but I'm confident it will work. --Keith :mrgreen: