Floating floor over basement concrete. (Artifact Recording)

Edited 6/15/2007 to include quick links to each individual page: 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20, 21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, 41,42,43,44,45,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78 Hello, After sifting through all the topics on floating floors, I've got just a few more questions if someone has some answers. 1. Suggestion/recommendation on thickness of neoprene pads to use. 1/4", 1/8", 1/2"? 2. What density, or Durometer, or Shore is (which ever term is used) would you recommend? 3. I'm using 2x4 studs, (due to ceiling height), but I have concerns about moisture in the basement in general. Should I use normal studs, or pressure treated studs? 4. The subfloor I intend to use 3/4" material. Once again, if there is moisture, I don't want the floor to bubble or swell from using particle board. Will one layer work, or is 2 better? 5. Vapor barrier. Should I lay plastic directly on concrete, or use another material? Someone suggested using roofing felt. This would allow the floor to "breath"? 6. Over the years, I have often seen where they used sand in the floor. I've originally been planning to do this, unless the mineral wool is a better option. Thanks, Aaron :)

bump for me too!

here yah go... 1 - 1/2" neoprene 2 - Durometer of 60 3 - There is a thread in this forum with a link Steve posted regarding basement insulation techniques. I'd Read that for greater clarification n what you should do. I think it had it do with building your wall out from the basement and using the pink formular type insulation on the basement wall,etc... I am trying to recall from memory but search here for that info it is very good and enlightening. 4 - Two Layers is the way to go for stiffness and deadening of sound. 5. - Look at Number 3. Keeping that floor and those walls dry is the main thing. So study what this information can provide with regards to techniques to keep the basement aerated 6 - Mineral wool is a better option plus it is water resistent, mold and fungi resistant, etc.... Bryan Giles

Here's the basement article, I would save it to your hard drive and study it - it will take a few readings to catch all the points for your particular situation. http://www.buildingscience.com/resource ... ystems.pdf Read the article for your answers to vapor barriers, I don't recall the entire thing and refer to it myself regularly. Durometer - 60 seems to be about the only thing available, 1/2" is deep enough to compensate for floor irregularities - if not, fix the sub floor before you float. One thing few cover on floating floors - rubber is a spring. Springs ONLY act like springs when they are NOT at the ends of their travel. When they ARE at the ends of their travel, they are NOT resilient at all, and could just as easily be THROWN AWAY. The only way I know of to be sure of the total amount of cross-sectional area of rubber you will need for your particular project (unless you're more of a mathmatician than I am) is to experiment - you want the total weight of ALL the floated stuff to cause the rubber to compress by at LEAST 15%, possibly 20 - Edit, 3/26/05 - I've been meaning to update this part for some time, to reflect newer data - actual range of compression can be from 5-25% - the trade-off is between longevity and isolation. You get better isolation with higher compression, but lose serious lifespan of the material. For this reason, 10% is a good compromise to calculate for. this includes EVERYTHING that will be supported by the rubber - floor, walls if they're floated on the floor, ceiling if it's supported by the floated walls, console, drums, EVERYTHING that is pressing down on that rubber must be figured in. Find weight figures for all your building supplies, do a material list to find out how many of each product, do the math, and get a close estimate of what everything weighs. Include musical instruments like pianos, organs, mainly heavy items - and anything that's permanent, like console, speakers, glass, doors, framing, etc - Once you find out what your total "sprung weight" will be, it's time to experiment. The way I would (will) go about this is to start with a very solid work bench - take a piece of your floor framing, oriented the way it will be installed (flat or on edge) and fasten a couple of pieces of lighter wood to the ends so that the framing piece is the center of a "U" - this will stabilize the piece so it won't fall over. If you're laying framing flat, don't bother with this step. cut a small sample of your rubber, no more than 1" wide, and at least 1/2" longer on each end than your frame width. Lay the frame sample on the rubber, all resting at the edge of your sturdy workbench. You will need access to measure some things later. Get a full set of encyclopedias, or some workout weights, something with a lot of mass - First, firmly push down on the framing sample so that you take any "slop" out of the interface between workbench, rubber and frame. Measure VERY accurately the distance between the framing sample and the top of the workbench, as close to the rubber as you can get. This is your "zero reference" - this is the thickness of the rubber WITHOUT compression. Next, start stacking weights on top of the framing member, directly over the rubber, til you compress by about 20% - make sure the rubber is not constrained horizontally in any way, or the measurement isn't valid. In the case of 1/2" rubber, you would need to add weight til it was only .4 inches thick (measured between your framing sample and the top of the workbench) - Weigh the total material you stacked up to accomplish this, divide by the total area (in sq. in.) of contact BETWEEN RUBBER AND FRAME ONLY, and you have the weight per square inch that's necessary to accomplish 20% compression. Divide your total estimated "sprung weight" by your "weight per square inch" figure above, and you have the total area of rubber to be distributed beneath your frame. Allow for a few extra pucks under areas where heavy things will be - if you're using a serious console, put a few extras under where the legs will sit - same in areas where a piano will be. Allow for twice as many pucks around the perimeter and under any other walls. Don't add extra pucks, steal them from less rigorous areas and re-adjust the spacing. You will probably find that laying frames flat will require too long a space between pucks for proper compression - If you need less floor height you can narrow the rubber pieces some, but watch getting too long a span between supports especially for flat laid frames. I know this sounds like a hell of a lot of work, and it is - still, NOT doing this is kind of a Crap Shoot; you may get lucky, or more likely you'll be back wanting an easy fix for having taken the easy way out. There isn't one. Just because you're not a physics major (neither am I) doesn't mean you can ignore the laws of physics and get away with it - if you don't believe that, jump off a 10-story building while swearing you don't believe in Gravity... Steve[/b]

Giles117...In response to Q#3, the only portion of the studio that will have wood studs, will be the floor. The remainder of the walls, etc, will be done w/ metal studs (for several reasons). As far as the walls, there will be space left between the block wall and the new framing. Probably about 4". I have some moisture problems w/ water trying to come in. I've already spent several hundred dollars in attempting to resolve it, and hope it does the trick. I've rerouted all drainage from gutters away from the house, and have used Drylok masonry sealant on the block in the basement. So far, all appears to be working well, except where there is a small crack that has resulted from some blasting near by (widening the road). I would love to use 1/2" neoprene, but I also have to be conscious of my ceiling height. My lowest point is 7' 3" (where the steel beam is). The rest is 7'10". So every inch is premium. At this rate, the floor alone will be 6 1/2" thick (I wish it could be more). Then I have the ceiling in addition, which will take up more space. Can I use 1/4"? Thanks for the link, I have read this article and found it informative. That was part of the reason why I had so many more questions. I intend on placing a dehumidifier in the basement, which is part of the reason for leaving the air gap around the studio and the concrete block. As far as the double layers on the floor, not a problem, just the $28.00 a sheet price tag w/ 350+ sq. ft of space x2. Knightfly...Yikes! Sounds like my wallet and bottle of aspirin have been sprung. I know it has to be done that way, now it's having the time. I don't suppose anyone has weights of materials handy? Thanks, Aaron

1/2" Neoprene is the way to go. Lay the studs flat instead. And go for a shallower floor depth. Just make sure you have that insulation in there and you have the floor floated with 1/2" neoprene (I am getting repetitive) You Will be fine. As Far as what to use?? Do you have a Lowes Nearby? Try the ChoiceDek laminated wood decking studs. They are water resistant. http://www.lowes.com/lkn?action=pg&p=Ve ... ml&rn=none Bryan Giles

I can't lay them flat, due to having to run conduits for cables, etc. Should I lay some type of material down directly on the concrete prior to the neoprene, insulation and studs?

If you are dealing with water issues I wouldn't lay anything to cover the concrete directly. How thick are these conduits? Try 1-1/2" PVC Pipe. Most 56 or more channel snakes are well under that size. Bryan Giles

I was planning to use 2" pvc. Maybe 3" in some area's (for multiple snakes). I don't think I will have much of a problem w/ moisture. Just concerned w/ the concrete sweating, or condensation. It's humid here in the southern states.

We have the same issues here in Michigan. Detroit River next door, lots of humidity in the air so I feel yah. The 1-1/2 was to get away with laying the studs flat Bryan Giles

I would prefer to use the studs on edge. It will give me a thicker floor for isolation w/ the insulation, as well as running fewer conduits for cables. I guess my main concern is just keeping the floor off of the concrete. I guess I could just not use anything underneath. I was originally planning to put the sand in the floor, thus using a barrier for moisture, but if it's suggested I use the insulation instead of sand, that's the direction I'll go. Should I use any acoustical caulk or anything around the outside, or leave it so it will breath? What about isolation from the other rooms? Will it travel under the floors cause problems?

The dehumidifier is a must, and it wouldn't hurt to use that basement article to thoroughly check out the rest of your location - see if there's any drainage things that can be incorporated, eave drains run out away from the house, etc - With that much moisture, I would try to solve that problem before building anything more. You definitely want to build so that air drying can happen when things get wet. Pressure treated wood if it's in contact with concrete, don't use sand if there's moisture because it will NEVER dry out as long as the moisture is around. On floor floating, there have been a number of people who've just built floating floors without all the measuring/math - some have LUCK, some don't but lie about it rather than admit a mistake, and some decide floating floors don't work because theirs didn't. The probable reason for the fairly high success rate DESPITE not knowing, is that anywhere from 10 to maybe 85 % compression will help SOME, so there's a big leeway for error and still have some benefit. It takes longer to do the calculations (obviously) but it takes a lot of the "luck" out of it. Your call. I've been gathering info for a table of material weights, but it's nowhere near complete yet. A bathroom scale will help if you have the materials handy, in fact that's one of my next plans when I visit Home Depot with some time... Here's a bit of a start, at least for drywall - Regular Drywall Panels. Panel Size - Weight - Lbs/SqFt 4' x 8' x 3/8" = ///45 lbs. //1.406 4' x 10' x 3/8" = //56 lbs. //1.406 4' x 12' x 3/8" = //67 lbs. //1.406 4' x 8' x 1/2" = //54 lbs. /1.6875 4' x 10' x 1/2" = //68 lbs. //1.6875 4' x 12' x 1/2" = //82 lbs. //1.6875 4' x 8' x 5/8" = //74 lbs. /2.3125 4' x 10' x 5/8" = //92 lbs. //2.3125 4' x 12' x 5/8" =//110 lbs. /2.3125 Firecode Core Panels 4' x 8' x 5/8" = /70 lbs. /2.1875 4' x 10' x 5/8" = /88 lbs. /2.1875 4' x 12' x 5/8" = /105 lbs. /2.1875 To convert lb/cu ft into kG/m^3, multiply by 16.04. To convert the other way, divide by 16.04. Concrete weights approx. 3600 lbs/cu yd when cured, about 3900 pounds wet. 133 lbs/cu ft, or 2133 kG/M^3 - MDF - approx. 68 pounds per ½” 4x8 sheet or 2.125 PSF, 53 PCF. Glass = approx. 3.58 times weight per unit thickness of sheet rock - roughly 161 lbs for 4x8 sheet of 3/8” glass. 161 PCF, or 2576 kG/M^3 - The surface density of ¼” plywood is 0.74 lb/sq ft, or 23.68 pounds per 4’x8’ sheet. The surface density of 3/8” plywood is 1.11 lb/sq ft, or 35.5 pounds per 4’x8’ sheet. The surface density of ½” plywood is 1.48 lb/sq ft, or 47.36 pounds per 4’x8’ sheet. The surface density of 5/8” plywood is 1.85 lb/sq ft, or 59.18 pounds per 4’x8’ sheet. The surface density of ¾” plywood is 2.22 lb/sq ft, or 71.04 pounds per 4’x8’ sheet. A dry 8’ 2x4 weighs about 10 pounds, 2x6 about 15.7 pounds; density about 4.28 PSF for 2x lumber. This puts 2x lumber at roughly the same density as a layer of 5/8 and a layer of ½” drywall. Celotex has an average density of 16.8 PCF, or about 39% as dense as gypsum wallboard. As far as your project, I'd strongly recommend taking this slow and thorough - moisture problems have completely rotted out construction in a couple of years... Steve

As far as your project, I'd strongly recommend taking this slow and thorough - moisture problems have completely rotted out construction in a couple of years... Steve

Hence my resoning for recomending you look into that choice deck. As it is plastic encapsulated wood. So rotting is a dead issue. Bryan Giles

giles117 wrote:

As far as your project, I'd strongly recommend taking this slow and thorough - moisture problems have completely rotted out construction in a couple of years... Steve

Hence my resoning for recomending you look into that choice deck. As it is plastic encapsulated wood. So rotting is a dead issue. Bryan Giles

Bryan, that might cover rotting - but it does not cover the health problems (some of them deadly in fact) associated with mold issues....... and dark damp areas are perfect conditions for this......... The last couple of years there have been some serious studies indicating that this is a much graver health threat than has been previously thought............ so i would not discount this easily.......... Before anyone begins construction in a basement with moisture problems - maKE certain the problem is solved (in one manner or another) prior to closing anything in. Rod

Thanks for the insight Rod. Never considered the severity of the Mold issue. So what can he do to solve this/plan for prevention? This is especially a concern for older construction. Any additional insight on how to build in a basement as well? Especially wall construction to allow the basement to continue to breath. I'd like to know as well. When I am complete with the 1st floor Studio, I plan to gut the basement and build a 5.1 mix room in the basement. Bryan Giles

Bryan, that PDF I posted earlier covers quite a bit of this - it's kind of dry the first 7-8 pages, but then it shows what goes where in several different scenarios... Steve

I've picked up some 1/2" rubber. What size strips should I use? The 2x4's will be on edge. Should I cut the rubber into 2"x2", or 1"x3", etc.?

Aaron, got your PM - hope you understand my answering that way - On your floor situation, so far I'm getting that you've changed from 2x6 to 2x4 construction (ceiling height, I sympathize) - What you've NOT stated anywhere in the thread that I can find, is whether you intend to build your walls BESIDE the floor or on TOP of it - also, whether you intend to suspend your ceiling, either with wires or RC (probably), or if it will be framed on TOP of the walls or INSIDE them (all viable options, some better because of height limitations) All these factors will enter into the size of the interface between your floor joists and the rubber, as this interface area is what, along with durometer, will determine the degree of compression of the rubber. You will still need to approximate what the TOTAL weight you're floating amounts to, and you'll need to try the test I outlined earlier in this thread to find out what it takes to compress your specific rubber by what percentage per given surface area. Once you get some real world figures with YOUR situation, you can figure the TOTAL surface area the interface should occupy - then you can divide the area of rubber you need by your total floor area (converting to square inches makes this easier) - remember, each inch of width (along the length of a framing member) for a rubber puck, when it's supporting a 2x board (1.5" actual) = 1.5 sq. in. of surface area. You need support along each 2x4 at LEAST every 5 feet to meet span requirements, assuming 16" joist spacing - closer is OK too. This gives you a range to choose from when deciding how WIDE to make your rubber strips. (By Width, I'm referring to the dimension that runs parallel to joists - this width will change the area of interface between joist and rubber. The other dimension of your "pucks" should be at least an inch wider on each side than the joists, or 3-1/2" total. The rubber MUST NOT be constrained horizontally, or it stiffens the resilience and changes the effective Durometer. You can, roughly, figure about 60 pounds for each 4x8 panel in your (floated) studio, whether plywood or gypsum; metal studs weigh very little, wood 2x4's weigh about 4-5 pounds each depending on moisture content. Your equipment you'll just have to weigh, or look up in manuals - you need the TOTAL sprung weight for your calculation. This leaves the interesting part, where I explained earlier how to measure deflection. I'm not sure how to make that part any plainer - if you still need help there, post back and I'll attempt a drawing or two when I get time. Oh, yeah, remember you can be anywhere from 15-75% compression and still be good, so it's not real critical. That's why you can just estimate using 60 pounds for wallboard. Again, springs are only springs when they are NOT at the ends of their travel. Hope that helped... Steve

Steve, yes I understood your PM. Thanks. :oops:

On your floor situation, so far I'm getting that you've changed from 2x6 to 2x4 construction (ceiling height, I sympathize).

The floor is going to be 2x4 studs. This was the plan all along. Sorry if I didn't notate this earlier.

What you've NOT stated anywhere in the thread that I can find, is whether you intend to build your walls BESIDE the floor or on TOP of it

Double walls all the way around. The inside walls of the control room will be floated on top of the floor. The outside "shell" so to speak will be directly on the concrete and up to the ceiling/floor joists. What I'm trying to decide now is when I frame the outer wall, should I leave it as frame and mineral wool only, or add drywall to it?

also, whether you intend to suspend your ceiling, either with wires or RC (probably), or if it will be framed on TOP of the walls or INSIDE them (all viable options, some better because of height limitations)

The ceiling I'm still trying to figure out. I've already filled all the joists above w/ mineral wool, but I need to float the ceiling somehow. I have that steel beam that is also in the control room, and have to work around this obstacle. I'll try and get these pictures developed and post a couple of the room. The layout that appears will work the best for my situation is the one John drew up on the other thread I have under studio design. http://johnlsayers.com/phpBB2/viewtopic.php?t=809 Back to the ceiling...I'm planning on framing the ceiling. I don't know if this will work out well or not because of height. I'm trying to figure out the angles I should use (remember I have that beam) for the ceiling. Should it be lower in the middle or higher in the middle? I've still got to decide on where AC ducts will go, etc. There is also a question of the walls. Out of all the web sites I've been to, there are several different methods. The main one I see here would be: Stud, RC1, 2 layers of 5/8 drywall. I've seen where the walls were: Stud, 5/8" drywall, soundboard, RC1, 2 more layers 5/8" drywall. (yikes). Then of course you have the ones that say to use something in between like a mass barrier of some sort. Any preferences? Steve, I went through this thread and didn't see anything on deflection. What are you referring to here? Inside walls/angles?

Maybe "compression" would be a better word - check my first post in this thread, on the first page. I described a way to check the amount of weight required for a given amount of compression of any given sample of rubber. Hopefully it's clear without having to draw a diagram - if not, it'll be probably a day or so before I'd have time. "What I'm trying to decide now is when I frame the outer wall, should I leave it as frame and mineral wool only, or add drywall to it? " - In almost any thread where I'm asked about wall construction, I try to explain about the number of "leaves" that should be in a sound wall. Basically, between any area and the area you want to isolate, there should be only ONE airspace - this can be (and should be) insulated with either semi-rigid or regular fiberglas insulation. What you do NOT want to do is to have 3 separate centers of mass (leaves) between any two places you're trying to isolate. So, if one wall has wallboard on its frame on only one side, and the other wall (or other side of the same frame) has wallboard on it too, you're DONE. All you can do from there, without making things WORSE, is to add LAYERS to the same LEAF. Period. Things that help - more mass, wider air gap, insulation slightly touching inner wall panels (damping helps reduce leakage through the wall) , Hermetic sealing of all surfaces, dissimilar weight of opposing wall leaves, all these will help. Multiple air spaces are BAD. Lightweight materials, generally, are BAD. Letting wall surfaces firmly touch ceiling surfaces or floor surfaces is BAD. Leave a 1/4" gap and caulk with acoustic sealant - gives an airtight seal without transferring vibration between surfaces. Ceilings can either be floated on walls using 1/4" neoprene, or suspended on wires with custom isolators on each wire - the trick is figuring out in each situation, how to get those TWO leaves and ONE air space worked into the equation. The goal is two completely independent shells separated by one air space. The closest you get to that, the better your results. One more ceiling method is to build walls up to within a narrow gap from the ceiling framing, then use Resilient Channel and suspend the ceiling wallboard within the walls, keeping a gap and caulking that gap after the wallboard is hung, usually 2-3 layers of it. This method usually gives the least loss of headroom. "Should it be lower in the middle or higher in the middle?" - Definitely higher in the middle if possible. You want the ceiling angle to deflect early reflections AWAY from the mix position. The only sound you want is the direct sound from your speakers, for at least the first 20 feet beyond your ears - otherwise, any reflections should be absorbed if their path is shorter than that. If you can't slope the ceiling up to the rear of your mix position, then it should be absorbed with at least 2" rigid fiberglas, preferably spaced out from the ceiling by an inch or two. Hope this helped... Steve

Steve, I attached some drawings on what I was inquiring about with the double walls. Maybe one of these 3 drawings will show what I was talking about or had questions to. Any one of them better than the other?

The top and bottom ones will give the best isolation, because of the increased air space. The middle one would be the most sensible to build, you could just offset the studs away from the block wall further for better low end isolation if you want. Whichever one you went with, you'd need to install a "perimeter Isolation board" around the floated floor, to make sure it doesn't contact the outer wall. Celotex or Homosote works for this. Caulk around it before adding the inner wall frame. RC isn't necessary on the lightweight 25 gauge steel studs, they are flexible enough not to benefit from it. If you're using the heavier, structural grade studs for load bearing walls, then you need RC on one leaf of the wall for an improvement of about 6-9 dB, roughly. You should "lose" the neoprene under the wall frames, just use a layer of pink "sill seal" from Home depot. Caulk each layer of wallboard as you go. I've posted methods for wallboard in several threads here if you're not sure what to do - search on "leaves" or "layers", those should come up for you... Steve

I'm using 20 guage metal studs. In some of the other research I was seeing on web sites, they were saying to use 20-22 guage studs. Plus I figured w/ all the weight of 2 layers of drywall, etc, it couldn't hurt. (Besides, I've already ordered and picked them up a couple hours ago. Even dumped half the load in the middle of an intersection on the way home...oops!) :shock: What do you mean by a "perimeter isolation board"? Where does this go? :? In the drawings, here's what I've got on the first & last pic... I have the concrete block (foundation), then I'm putting a couple inches of space to keep everything away from the wall (because of moisture), placing a 3 5/8" metal stud wall w/ 4" 4lb Roxul between the studs, then I have whatever space will be in between (due to angles for inner wall), and the inside wall made of 3 5/8" metal studs and also insulated w/ 4" 4lb Roxul between the studs. Studs will be on 24" centers. Then I have the RC-1, and then 2 layers of 5/8" drywall. Does this sound right? Sorry for the pun. LOL. :D Thanks, Aaron

Perimeter isolation board is the board you put around the perimeter of your floated floors to keep them from accidentally contacting the walls. It can be anything "squishy", like Celotex, Homosote, Neoprene, rigid fiberglas board - caulk in place before adding inner studs. If you're concerned with moisture, I'd go with the rigid fiberglas, and maybe only chunks of it spaced out so more air can circulate around the concrete. The 20 gauge are usually rated as "structural", and are stiff enough to get a worthwhile advantage from using RC on one leaf. Probably are better when only one side of a frame gets paneled. My only other concern would be the use of 4 pound insulation. If this is 4 pounds per cubic foot, that's a bit dense for wall insulation. Using that will bias your isolation more towards upper frequencies than lower; lighter weights favor the lower frequencies when used inside wall cavities. 2.5 PCF is what USG recommends for a balanced performance. If you increase your air gap by an inch or two, you should get some of that lower frequency performance back, or if it isn't too late to find the lighter stuff I'd try to do that. Another thing to consider on walls: If you have concrete block outer walls and are not super-concerned with sound proofing, you could stick to a single layer of sheet rock on the inside studs (with insulation still) and lessen the need for as many bass traps in your room (the single panels will act as a panel absorber) - the downside of this is that you lose isolation, so if that's a problem then you'll just need to build traps for all the corners most likely... Steve

I don't think the floor will be close enough to the wall to really be concerned with this. I'm not placing anything within 2 or 4" of the block. I want the dehumdifier to be able to pull all the moisture out of this cavity between the block and the outside wall of the control room. Attached is a rough layout of what is looking like will be the layout (not final). I started to draw this plan more to scale from Johns idea on the studio layout.