Concrete perimeter wall

Hi Steve, First I will like to thank you for all these great topics on these site.Very very helpfull! This is the link to my post at studio design! John mention that you could help me how to make a good isolated wall from concrete blocks! http://johnlsayers.com/phpBB2/viewtopic.php?t=1602 The big challenge is that we have......an......airport at 2 km!The spl outside my home is about 90db.Could I make a studio with no airplane sound passes thru the walls? Thank you vey much. Yiannis

Hi, Yiannis, welcome - Wow, 90 dB of garbage to tame - this can be done, it is mainly a matter of what materials are available to you locally and your budget and building abilities. Considering your plan to use concrete blocks, one of the first things you will need to find out is whether your existing construction can support the weight of SOLID concrete outer walls - with that much noise to control, you will need somewhere between STC 65 to 75, and that's not practical with hollow blocks. You will also need to find out whether your floor can handle the extra weight of floating floors - you may need to find a local engineer to help you with this part. In order to isolate your rooms from that much noise, you need to use most of the methods of isolation that are available - these include floated floors, sound-lock doors, double-leaf, high mass walls, double-leaf ceilings, etc - It looks like you have enough room for a nice facility - next, you will need to take a "crash course" in sound proofing - most of what you need to understand can be found in the "sticky's" section at the top of this Construction section - please read through these, and follow the links to further information. The more you understand from these, the easier it will be to NOT make serious mistakes in construction later. Please do NOT make the mistake of following recommendations by local, NON-sound trained construction/engineering people - one of our members did that, and is now trying to find enough more money to fix what should never have been built the way it was done. Sound proofing is not an intuitive thing, and almost nobody working in normal construction understands what works and what does not. Doors, windows and air conditioning are probably the biggest challenges when building a high isolation facility - these will all take extra care if you are to keep isolation to a maximum. Some of the things we need to discuss - your level of building experience (or if you have a friend who is experienced) , whether you have other building materials available, such as gypsum wallboard (for inner wall layers), wood or metal framing materials, what tools are available to you, and most of all what your approximate budget is. Once these things are considered, we can start figuring out the best way for you to go about building your studio quiet enough for airplanes not to bother... Steve

Hi Steve, Now,thats a really fast response!!! Thank you very much for all these infos! Well my budget is about 30.000-45.000 euros and if trully needed I might go for a 60.000 euros.:roll: I can find all the materials needed here in Greece gypsumboards by Knauf. About rockwool I can find 70kg-100kg-30kg and glasswool 30kg-50kg. Wood and metal framing(better wood). Thank you very much and be patience with my English please!:oops: Yiannis

One comment here.......... This is one of those few times where I would reccomend considering the use of hollow concrete block and sand fill in all the cores not required to have reinforcing and structural grout. You get better LF TL values with sand than you do with solid block. Rod

Rod, that means a lot of work and extra weight,right? Is there a measurement about how heavy a studio construction could be,including all the insulation and the outside concrete blocks? Take care. Yiannis

Yiannis, There is no magic formula that answers your question. It takes mass to block LF transmissions. Period. How much mass is required depends on what the source is......... in your case it amounts to a lot........ You are going to (at some point in time) hire a local structural engineer to determine the answers to the questions raised by Steve..... Can your existing structure take the additional loads that will be superimposed on it by the construction you require in your case. If the answer is "yes" then it's easy - if the answer is "no" then the new question becomes - "what has to be done to the existing structure to carry the required loads ?" If the cost of doing this is not within your budget - then you have 2 choices - either increase your budget - or decrease your isolation. There aren't a lot of alternatives. One of the problems that exists here is the fact that we cannot determine (and will never be able to determine) what your structure can carry. In reality - the best thing you could do would be to get the engineer now in order to determine what loads you can add - without knowing this none of our answers really have any meaning. By the way - just for the record - sand filled block really has no greater weight than solid block. Rod

Rod, I am already waiting for an engineer to check my home! The only think i know is that the ground floor is constructed in a way that I can build two more floors above it!Now there is only the 1st floor(where I live) An engineer told me that a new house -above- from cement and blocks weights about 80 tons!Maby more. I think that is gonna be ok,but better wait to see what an engineer will say! Yiannis

Yiannis, Rod is right on this - here is a canadian study of masonry walls - http://irc.nrc-cnrc.gc.ca/practice/noi1_E.html if your engineering study shows that your building can take the weight, I planned on recommending FILLED 200mm block for the outer wall, and an inner, FLOATED wall frame with 3 layers of drywall - these would be separated by about 200mm (from inner face of blocks to the first drywall panel), the inner surface of blocks painted with two coats of concrete sealing paint, and the cavities filled with fiberglass insulation. This wall construction has a theoretical STC of 92, with the Transmission Loss at 50 hZ calculated at around 47 dB - in REAL life, the figures are always WORSE. Just how MUCH worse is determined by things like accuracy of construction, proper sealing, any wall penetrations, coupling to other parts of the structure, etc - typically, anywhere from 6 to 12 dB less than calculations is what you end up with. Your floors will need to be floated also- when asking about load bearing capability, find out if your structure can stand another 160 KG per square meter - that's about what would be added with a 50-60 mm concrete floated floor system, plus additional support for interior walls - The MAIN point I would like to make here - even though we can advise you on GENERAL methods for better sound isolation(we haven't even got to acoustics yet), there is NO WAY we can actually ENGINEER this project for you from a distance - you will DEFINITELY need to find a local engineer (preferably with acoustic background) for all the detail work that will keep you from causing your building to collapse. If you don't remember anything ELSE from my comments, remember this paragraph. If you only can find a local engineer who does NOT have acoustic background, perhaps he can also join this forum and we can help him get "up to speed" on acoustic considerations - as I mentioned earlier, ignoring this common lack of knowledge can be costly and painful, ask Geronimo if you want an example... Steve

Steve, I know that both of you are right dudes! There isn't any acoustitian engineer here because I don't live in Athens. No one is involved on sound here!whatever I do I HAVE to do it on my own. I know that sometimes I am asking stupid questions...but thats the only way to learn. ?s the floating concrete floor essential?I mean isn't a floating floor from wood ,gypsumboards and rockwool enought? The blocks will be filled with sand right? If I plaster and paint both sides of the blocks is it better? Plasterboard,drywall,gypsumboard,all are the same thing right? About filling the cavities with fiberglass,which desity please? Forgive my ignorance. Yiannis

Yiannis - if it's aeroplanes that are your problem then your ceiling is going to be a main consideration as well ;) cheers john

John brings up another point I hadn't gotten to yet - your entire studio will only be as good as the weakest link, and airborne noise definitly calls for a well-designed ceiling. I'm short on time right now, but will get back to you on ceiling/roof considerations. Yes, a wooden floated floor will help more than no floated floor - for lower frequencies, though, the heavier mass of the concrete lowers the resonance (mass-air-mass) of the floor which helps lower frequencies such as rumble from jets. BTW, I don't believe there is a stupid question, other than one that isn't asked - how else do we learn? IF you have an engineer working with you, that's the main thing - we don't need structural failure. The trickier parts we can help with, either through you or directly (if your engineer wants to join the forum) Gotta get to bed now, work starts in about 6 hours... Steve

John Sayers wrote:

Yiannis - if it's aeroplanes that are your problem then your ceiling is going to be a main consideration as well ;) cheers john

John-that is definitely my main problem!Its not eveyday ...but when it happends there is a problem.:x What I am doing now is to stop the session for some seconds and start again.My room now is not isolated. I am thinking about making the most isolation at the recording spaces and less at the CR.Is there going to be a problem if a small about of LF passes in the CR? What is your opinion please?

Definitely, from a cost-control standpoint, your recording spaces should be the first to be as isolated as you can get them - you don't want that "perfect take" to be ruined by an airplane - Also, isolating those spaces from your CR will let you set mics using your CR speakers (better and easier than headphones) - What you put up with by not isolating the CR as well as the rest - if you're tweaking a mix and a plane flies over, you start again to make sure that noise isn't recorded, or that it sounds like you want it WITHOUT that rumble, etc - In short, if you're planning on this being a professional studio, you should isolate EVERYTHING as well as you can - if it's more a hobby or "project" studio, you may want to spend the extra money on gear or acoustic treatment... Steve

Steve, It is going to be a pro recording studio!I have the gear needed for that(Avalons,tubetech,cranesong,lexicon,otari,klarkteknik,ensonic,soundcraft,apple,motu,genelec,yamaha and more) About CR isolation maby ist not as critical as in the studios in my opinion! An extra noise for 15sec is not going to ruin my mix. But if my budget is enought I can do a complete isolation all over the studio! Could you please answer this to me and some of the other questions that I have post? thank you very much for your time.

Yiannis - Were these the questions you need answered? The blocks will be filled with sand right? Yes If I plaster and paint both sides of the blocks is it better? Yes, it adds probably 3-4 dB depending on the porosity of the blocks. Plasterboard,drywall,gypsumboard,all are the same thing right? Right. About filling the cavities with fiberglass,which desity please? Inside wall cavities, you want to stay below 3 PCF (48 kG/m^3) - lower density tends to improve low frequency Transmission Loss, higher density helps higher frequency loss but loses Low Frequency isolation. If I missed some questions, let me know which ones... Steve

Steve, thank you for your reply! About the blocks I tend to use are made from pumice and cement. The ordinary blocks have two cavities,right? These have six cavities and are 11kg each. I don't know if this is important. The seller told me that they have a TL of 68db.I don't know if this TL covers the entire frequency range. What do you think about the 45.000 budget? Thank you.

On the blocks, what are the exact physical dimensions, L x W x H ? And what is the size of the holes, and the web that runs between each hole? As to budget, I would need to know more about costs of materials in your area - for example, the cost per sheet for 15mm gypsum wallboard (and what size sheet that is) the cost of 37mm x 90mm wood boards, OSB, MDF, and plywood in 19mm thickness, cost per block for the blocks you mentioned, and if you intend to hire any/all of this done the typical rate for construction labor - If you were to hire a studio built in the US, you would be lucky to get 30 square meters of space for $45,000 - if you do all the work yourself, you could get 2 to 3 times that much for the same money. In Greece, you may have access to cheaper labor and/or materials - once you find out the costs I asked for, including typical labor for construction and whether you plan to do most of it yourself or hire it done, we can get a better idea... Steve

Hi Steve, these are some infos and photos about the blocks. 1) Lavablock 24. 39x24x19 12,9 kg 2) side view of lavablock 20 3) Lavablock 20 39x19x19 11kg about the other materials I am still looking for good prices. I will let you know. thanks

Steve,what do you think about these?

Never saw anything like them in this part of the world - is that a hole in the middle, presumably for steel re-bar? Looks like if you "buttered" the entire block face when stacking, you'd get the equivalent of solid concrete from an acoustic point of view - I don't see why they wouldn't work for your heavy outer leaf... Steve

Steve, I will call on Monday to get some info about the hole in the middle. Are the spaces on these blocks helpfull for sound isolation? I have count that I will need about 1800 blocks for the outer wall.Thats about 20 tons!!! If you take a look at the plan the bottom is north.The planes are on that direction.Should I consider to build the CR there(north) and the studios at the south?Or its the same no matter I do? would you please take a look at this? http://www.ytong.gr/Network/Network_Frameset.htm I know its Greek to you! These are YTONG blocks,a lot lighter but I dont know about soudproof. Thank you very much.

Yiannis, you're right about that site being "all Greek" - even the pictures confused me... :cry: If those blocks are lighter, they are NOT what you want - the closer you get to solid concrete, the better. If the first blocks you posted pix of are what they look like, they would be the best of what you've shown so far. In order to get good isolation from your walls, you will need this heavy solid outer shell, then a space full of insulation, then an inner, somewhat lighter wall (like 2-3 layers of gypsum wallboard all on one side of the frame) - once this outer double shell is done, you can worry about acoustics (sound proofing and acoustics are almost totally un-related) - the same applies to floors and ceilings - if your existing roof is flat and made of masonry, and is strong enough to support the rest of the studio construction, then all that would need be added is the inner floated floors. This would be mandatory in the tracking rooms, and (sort of) optional in the CR - As to ceilings/roof, the same laws of physics apply - you need two masses separated by air/insulation in order to isolate effectively. Besides that, you also need the roof to keep the weather out, and to still be ventilated enough NOT to cause mold or rot. This generally means that you get things sound proofed (by doing a double leaf as I explained) and THEN cover it all with a ventilated but weather-proof roof. These "rules" are especially true of your situation - the low frequency rumble of air planes will literally shake the ground, which will transfer through your building and into your rooms - this is why having fully isolated "room inside a room" construction, including floated floors, is the only thing that can stop this kind of noise... Steve

Steve, I will make a plan for my roof and post it here but this is what I don't understand so far:oops: Would you please explain it? "Besides that, you also need the roof to keep the weather out, and to still be ventilated enough NOT to cause mold or rot. This generally means that you get things sound proofed (by doing a double leaf as I explained) and THEN cover it all with a ventilated but weather-proof roof. " thank you!

Yiannis, here is a VERY basic drawing with more explanation - there are no construction details, this is just the CONCEPT of what needs to be done... Steve

Steve, this is what I am planning to do for the outer part of the roof. Above the metal frame will be a layer from wood battens, then a layer from cement (whatever thickness is desirable) Afterwards a layer from sheetbutimen will be installed so no water passes thru (I don't know if this word does exist ,but that what it is been called here "sheetbutimen"). Last the ceramic tiles will take place. The outer mass shell is going to be ONLY the perimeter of the building.I mean that inside I will be able to see the metal beams that support the outer roof. So if the roof has to be ventilated how am I going to do it please? NOT to build the perimeter wall to the roof height,right? That way isn't risky for the moisture or dust to get into the construction? Thank you.