How-To: Styrofoam Concrete

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How-To: Styrofoam Concrete

[The images for this post were removed at the request of the blogger whose work we linked to]

Concrete that uses chunks or beads of expanded polystyrene (EPS) foam as aggregate has lots of interesting applications. It’s lighter, for one, so if you’re casting something intended to be portable (like Halloween yard tombstones) “EPScrete” can save you some lifting and groaning. It would also be expected to have better thermal insulation properties than plain-Jane concrete, and of course there’s the green angle: EPS is tough to recycle, and any that gets cast into concrete objects doesn’t end up in landfills (at least not immediately).

And while there is rather a lot of general discussion about EPScrete, online, there doesn’t seem to be much by way of hands-on instruction. That’s why I was pleased to discover this series of short posts from Nori Lamphere at her personal blog Our House, who did a great job, around this time last year, of keeping an online notebook describing her construction of an EPScrete wall using shredded foam slabs recycled from packing inserts. There are eleven posts in the series, which starts here.

Though you can make EPScrete using new polystyrene beads, Nori wanted to use directly recycled material, so she needed a way to grind up the foam slabs quickly. She started out using a wood chipper (which she does not recommend), but eventually switched to a homemade electric foam shredding machine, and developed a specific volumetric mix which includes recycled latex paint added to improve workability and flexural strength. Besides the recipe, she gives a detailed mixing protocol, and goes on to describe the construction of the wall itself.

EPS-crete wall

53 thoughts on “How-To: Styrofoam Concrete

  1. Nori Lamphere says:

    Sean, you’ve used this information without my permission. That’s bad enough, but the information is wrong at least by implication. The wood chipper makes a horrible tool for shredding foam. I’ve requested the post be removed.

  2. Sean Ragan says:

    Sorry you’re displeased! I’m sure my editors will accommodate you. A shame, though, since you’re one of the few folks who’s bothered to publish detailed instructions on this process.

  3. C. Visnesky says:

    Sorry she is Displeased?? Geeze, Sean maybe she has a right to her own work and inventions? You are WRONG on this one. If you thought the info was so great you know you should have asked And thanking her when you didn’t even ASK for permission in your online rag is reprehensible. She doesn’t owe you or anyone free access to reproduce without permission. There is too much infringement going on on the web, with poor excuses for the theft. Take the high road if you want to keep your good name.

    1. Sean Ragan says:

      Yes! I am sorry she’s displeased! I’m sorry you’re displeased, too! I wrote this post, like all my posts, because I think Nori’s work is awesome and wanted to share it with our readership. I do not question her right to her own work or inventions, and did not in any way intend to impinge on those rights in posting about how cool I think they are.

    2. bonkers says:

      C. Visnesky, what alternate universe do you live in? Sean stole nothing and clearly attributed all the links and processes in a positive way. Your outrage is unfounded and accusations of theft are ridiculous slander. Sean thanks for all the great work you do I and numerous others have benefited from it. As for the author why do you have your site online? If you want to keep this private then do so. Posting it online without a firewall and complaining of links to it is akin to streaking and being offended that people notice.

    3. Travis says:

      I don’t see Sean being wrong at all. He saw an article he liked, he shared it with others. He did not claim her article as his own, in fact, gave her full mention. I would have followed the link to her site and read the info, but not now. It appears she does not want the readership.

      I did some crushing of EPS to use in a foundry furnace, and found the easiest way was to break a block in half and rub the raw edges together. It just tears itself apart. Misting with water will cancel the static charges keeping the balls from sticking to everything. I’m sure that someone could build a simple machine that rubs two pieces together to automate the procss.

    4. emc2 says:

      OK, First the original author is not the inventor. This concrete composite material has been used for more than 30 years. Look up Rastra. She simply reversed engineered (through trial and error) a solution (formula) that worked for her. The formula is available by the suppliers of raw components that go into concrete products. Experiment and find your own way. Feel like sharing do it directly on a site like make. Fiberglass is treated when used in concrete. Plastic fibers are used to prevent cracks. Chemical additives can make it water proof – chemically. Latex is used as a admixture – exterior latex paint works too – makes concrete flexible and adds some water resistant properties. Want to try something cool use saw dust, coffee grounds or glass to the mixture. Add metal grindings, copper sulfate, iron oxide, and get cool colors.

  4. Gareth Branwyn says:

    Sean was only following the general practice that we (and most all blogs) follow: We see something we think is great, we post about it, we link to it, and we thank the person for the thing we’re pointing to. We’ve been following this practice since our launch in 2005, have done thousands of posts since, and have had only a couple of complaints. Most people are happy to get the attention, recognition, and the links to their projects.

    Nori: I assume you do NOT want us to use your images? If that’s the case, we will remove them at your word. We will not be removing the post. We’ll just remove the images and make a note that they’ve been removed at the request of the author.

    Sorry to have caused you any consternation.

  5. Zippy the fly says:

    Yes, please remove it all immediately

  6. Kris Lee says:

    I’m confused. I checked the page of question and I did not see any commercial interest behind that (no ads, no book links etc). Then why is there fuss about it? I would never ever found that page even though I have interest about such building materials.

    You get a review, you get more people to know about your doings, maybe even to be a regular reader of your blog and you complain about it. Are you nuts?

    Having no publicity in like writing into drawer. This is what you are after?

  7. Kris Lee says:

    I actually have a question about the EPScrete. You can pour a ceiling from normal concrete but can you do the same with EPScrete? Or can you pour longer blocks from it like lintels over doors and windows.

    Do you know usual isolation properties of EPScrete?

    In my opinion the most reasonable construction would be a EPScrete inside, then layer of stryrofoam and then EPScrete again. That would give the construction a good insulation properties, strongness and fire proofing.

    There is also material that is called “Porenbeton” in German (, most notably Yotong. How does EPScrete compare to this?

    1. skr says:

      As you can see, they only use this for in-fill. The structural qualities are not that great. The strength in concrete comes from the aggregate. You could probably trowel this onto a ceiling, but I wouldn’t try pouring a structural roof slab. The porenbeton is an aerated concrete with superfine sand as aggregate. The evenness of the aeration is probably greater with that and therefore its probably stronger than this eps formulation. It should be good with freeze/thaw though.

    2. Bruce says:

      About your question on panels for the ceiling: I make an EPS/concrete panel from recycled styrofoam, and my own fiber cement mix. I also have large blocks to construct fences, buildings, ect. I’m currently making such panels with a 1/2″ recycled cork panel laminated to it. This will give me added insulation to the panel, as well as sound proofing. Our blocks will give you the most r-value you can get out of any product, once the cells are filled with concrete, and rebar(up to r-60). I’ll have youtube videos, and photos up on my web site soon.

      1. sparkmike77 says:

        Bruce, how does it handle freeze/thaw? We get temperature variation from about -40 Celsius to about +35 Celsius through the year, would your approach be able to handle that?

        1. Bruce says:

          I think it will be fine, as I have a freeze/thaw agent in my polymer. I live in the desert, however it gets to about 20F to 115F. No problems so far. I know it’s not nearly as cold as you get, but we could add a bit more freeze/thaw if necessary for a custom blend. I don’t think its necessary, but doable.

  8. Daniel Morgan says:

    As far as I can tell Sean didn’t attempt to duplicate the information on the site, just give a preview of its contents and point people in its direction. When someone posts something to the web, they are engaging in an act that explicitly shares that information with the public. That doesn’t make the content public domain, but when someone digs hard enough to find it and then directs a large readership to it, that’s generally considered to be a fortunate event and an opportunity for the author to be appreciated.

    From the tone of the first reply one might think Sean either carbon copied the site entirely or stole the material from the owner’s filing cabinet during the night.

  9. Christopher Morse says:

    I was happy to see this post on Make last night. I am glad Ms Lamphere took added step of publishing her efforts. It’s something I struggle with. I am interested in this subject and as a result of this post spent some time reading more of her blog and researching the mechanical properties and creation of EPS concrete. Thank you to Ms Lamphere for the work and to Make for bringing it to my attention.

    Presumably Ms Lamphere objects to the use of her photos on the Make website. The Make staff appear to have made a timely and responsible effort to remedy the situation.

  10. Jack in Tennessee says:

    If someone doesn’t want to share information, not putting it on their we site is a good start. … The original site is ‘unavailable’ because of this traffic being sent their way.

    It also is not fully on which has walked their site in the past. … The original site authors should probably go there and have all associated information pulled too if they don’t want their ‘personal information’ propagated further.

    Oh well … time to get on with life … I was just interested in the mix they used (foam vs portland cement vs water) that worked well for them. …

  11. sparkmike77 says:

    The problem with the complaints of folks regarding The original Author’s response is simple: you seem to think hosting, badwidth etc are free. They aren’t and now her site has a lovely “Bandwidth exceeded” message, and nobody can read it. By bringing Make’s readership you have essentially knocked her site offline.

    May I suggest contacting the author and offering to host an article or content on your own servers next time? Or at least the images? “I’m a blogger, it’s what we do! Always have!” is hardly appropriate. Isn’t the Maker movement about doing things in innovative and less destructive ways? Or possibly even the spirit of co-operation?

    Poor form Sean, but forgiveable. Gareth, your sense of entitlement is disgusting.

    1. Daniel Morgan says:

      The vitriol from the anti-Sean/anti-Gareth side is strange and incomprehensible to me. Make has been nothing but respectful and accommodating.

      And I rarely see these bandwidth exceeded messages anymore. They’ve become something of an artifact from a bygone era of the web. It used to be common for popular blog sites to knock sites down with their traffic, but not so much anymore. And even then, it was generally seen as an honor to have your site temporarily loved into submission.

      I think this is all a tempest in a tea pot.

      1. sparkmike77 says:

        I’m hardly anti-anyone. I have enjoyed many of these posts in the past, and the central reason I feel compelled to comment is that the staff of Make: have always held themselves to (what to a subscriber appears to be) a very high standard. They are however human and mistakes happen. It is their reactions to the author’s request I find baffling, especially the “We’ve always done it this way, and we will continue to do whatever we please with your hard work” approach.

        I hardly ever see bandwidth exceeded messages anymore either, but the fact remains there is one here and Make’s traffic at least contributed if not caused it. The content author’s site is unavailable because of the actions of this one.

        YOU may consider it an honor, the author obviously does not and has stated as much. It may be a great honor for a pig to be slaughtered for a feast, but I doubt the pig sees it that way. (Please note I am extending to the point of absurdity, I am aware of that and am using it to illustrate a point)

        Ultimately, attribution is NOT permission. It is still not legal to use copied code in a program in whole or in part, regardless of attribution, if the license prohibits it. While there may or may not be legal implications for using the photos (Not a lawyer, don’t care) there is a moral one. The author should at least be asked and respected.

        Is Make: so opposed to using their own resources to drive the traffic that drives their advertising? Is it ok to exploit another person’s resources to better yourself while doing them injury? How many critiques of that precise behaviour has Make: posted? Phillip Torone essentially drives his posts regarding opensource hardware ethics etc. from that platform.

        All of this is without mentioning that the author feels the post misrepresents her content.

        1. Wally SirFatty says:

          You certainly like to hear yourself talk.

  12. Wilson! says:

    So the author has (rightly or wrongly) requested the article be taken down, and here we are 13+ hours later and it’s still here. Not cool, Make:

    1. Sean Ragan says:

      Excuse me, but I am the author of the article you speak of, and I have made no such request. Corrected, your comment reads “So the subject of this article has (rightly or wrongly) requested that the article be taken down and here we are 13+ hours later and it’s still here. Not cool, Make:”

      1. sparkmike77 says:

        No Sean, you’re the author of a blog post reviewing the author’s work.

      2. Sean Ragan says:

        Please read Wilson!’s comment again carefully. “The article” clearly refers to this article, on this page, hosted at That I am the author of that article is beyond dispute. I have not requested that it be taken down.

      3. sparkmike77 says:

        While “The article” may clearly refer to the above posting “the author” equally clearly does not. “Excuse me, but I am the author of the article you speak of” is true, but you are NOT the author referred to. Also, why am I unable to directly respond to your comment?

      4. Sean Ragan says:

        Whether Nori is the “author” or the “subject” of this article, here on, is a critically important distinction, which is why I bothered to correct Wilson! in the first place.

        If you were going to advance the general idea that anyone who was an unwilling “subject” of an article should have the right to have it removed from publication, I think you would have a hard time reconciling such a position with the established traditions and laws protecting the free press in much of the English-speaking world.

        If, on the other hand, you were going to advance the more specific idea that anyone who was an unwilling “subject” of an article here on should have that right, or at least that we should be prepared to extend that goodwill, I might be prepared to listen. But I think even in our particular case, we can’t afford a blanket policy that anyone who is upset with their coverage here can expect to have it removed. Sony, for one, might’ve recently benefited from / abused such a policy.

        The commenting restriction you are concerned about is inherent to the software we’re using, which I think is supplied by WordPress VIP. Replies can only go three levels deep. It has often vexed me before, but it does apply to everyone equally, and I have not “locked” or otherwise restricted your ability to comment as you like, anywhere.

        1. Jake Spurlock says:

          Comment threads, five levels deep!

          1. Sean Ragan says:

            Jake Spurlock, you are a magnificent human being.

        2. sparkmike77 says:

          Your contribution was not nil, but it was certainly secondary to the content linked, even using her images as a page header.

          For the rest, I’m not comfortable with accepting ‘normal practice’ as ‘best practice’. I suggest that it would always be best to err on the side of over-caution, especially where there may be unintended costs to your source author.

          At the very least contacting them may yield additional information and sources for your work and at worst you may need to find alternate sources that may welcome the attention

          1. Sean Ragan says:

            Normal practices are never “best” practices. In fact, no *actual* practice is ever absolutely “best” practice. To quote Emerson, “around every circle another can be drawn.”

            You too, Mike, must make practical decisions every day that have potential moral consequences you simply have to ignore, because you don’t have time to consider them all and carefully maximize utility for all parties involved. When there’s a traffic jam on your preferred route to work, do you carefully consider which is the most ethical alternative before deciding? Which is the most environmentally responsible? Which is the most respectful of the time, energy, rights, values, and mental well-being of your fellow drivers? Which is most respectful of the rights of the residences and the businesses along those various alternative routes?

            You may very well do all of those things, but even so, whatever the limit of your personal capacity to maximize utility for everyone, everywhere, in all your choices, we can draw another circle, around that, which is beyond your capacity to do so. Ultimately, we all have to accept moral compromises. Even you. In my previous comment, I have explained mine, and how I live with it.

            The last word is yours, BTW. Feel free to take it, below.

      5. sparkmike77 says:

        I did not mean to imply that you were responsible for the limitation on commenting, only that I had noticed it when trying to reply. Odd limitation, but I imagine it keeps lateral scrolling down.

        I didn’t/don’t want to discuss a person’s rights (because the vary from country to country, state to state, etc. and the internet is largely an international audience, contrary to the opinions of the US House of Representatives). I am very much interested in the ethical questions posed here.

        I would argue that posting what amounts to a summary or review of another person’s work should involve more than attribution, especially when said content is hosted externally on systems the author is paying to maintain because it may result in increased costs or time loss to the author.

        If the author is in some way compensated (which is often done incidentally by increasing traffic to an add-supported website) in a way they find acceptable, then the arrangement is beneficial to all. The Reviewer is compensated for the time they spent discovering, exploring and summarizing the Author’s work, the company that hosts the review is compensated by increased traffic (possibly expanded readership) and the intended audience is compensated for their time with the information they were interested in.

        This difficulty for me comes when compensation is not in an mutually acceptable format. For example, I would prefer to be paid for consulting work with service-in-kind or useful (to me!) equipment so that it is non-taxable because it changes the way taxation applies to the transaction and I get greater value from it. If you did not know that and offered me a cheque instead I would not be as receptive. If you had asked me upfront, it would have avoided assumptions on both sides (My assumption that you understood my preferred method of payment and your assumption I prefer direct financial compensation) and produced a transaction where both parties walk away with something of value.

        This importance of this principle is reinforced in this case by the fact the original author was unaware that any such transaction took place, and was penalized in a way neither of you expected. Make: and you (assuming you were paid for your work, which is an assumption I am making) and the audience (all of us accessing this content through this page) profited from the transaction, but the content author suffered.

        You had no reason to expect the reaction you received because you did not know that the compensation you brought (increased traffic and visibility) was not acceptable to the other party. That situation is avoidable by contacting the content author before posting your commentary/summation.

        1. Sean Ragan says:

          Would it be fair to characterize your argument as a kind of “consensual blogging” ethic? That we should not link out without getting permission from the linked siteowners first?

          1. sparkmike77 says:

            Essentially yes but only insofar as it is a direct summation/aggregation of content. I don’t think it would be a good idea to apply it to events in the world at large or reporting on them. I can’t really imagine a scenario where compromise would be impossible for handling freely accessible content, and I expect there are already similar arrangements for paid content.

            Your reply also demonstrates the value of brevity in debate, as skill I have apparently yet to master.

          2. Sean Ragan says:

            Seems like the views in this thread keep getting narrower and narrower.

            Yes, that was a joke. [Thanks, Jake!] Going back up a couple levels here.

        2. Sean Ragan says:

          Well, I am a touch put out by the suggestion that my own authorial contribution here is essentially nil. Yes, this post is mostly about Nori and the work that she shared, but it also provides background and additional information that her posts do not (or did not, in the unhappy event that they will not be coming back). My “explainer” post gives a general background of what EPScrete is, what some of its advantages are (though I missed mentioning the drawbacks, like decreased strength by most measurements), what EPS stands for, why latex paint would be a useful concrete additive, and the fact that EPScrete can be made from “virgin” styrofoam beads (like beanbag fill). Though my memory may be faulty, I do not recall that any of these points were mentioned on Nori’s pages.

          But, for the sake of argument, let’s allow that this post can be reduced to summation/aggregation. If the main purpose of a post is to briefly explain and direct interested readers to a third party site for further details, are we right to operate under the assumption that our outbound links are always going to be welcome?

          I don’t know.

          For mostly practical reasons, I am comfortable joining most of the rest of the blogosphere in saying “yes.” Getting explicit permission for every outbound explainer link would make the already demanding job of maintaining an interesting blog much more difficult, and our readership would, I think, suffer as a result. Which is a compromise I personally would prefer not to make. In choosing, for what amounts to utilitarian time- and work-saving reasons, to operate under the “you don’t have to ask” principle, I am comforted by a couple of thoughts:

          1) A person who publishes work on the web is, by the very act of publishing, signaling that they want it to be seen.

          2) A person who wants to be asked before receiving links is always free to say so, explicitly, on their pages. In that event, I would either do as requested and ask permission, or simply pass on the post.

          1. sparkmike77 says:

            Sorry that this conversation is now wildly out of order.

            I would actually like to continue this debate on a more appropriate forum (email, etc if you’d be willing).

            I don’t know that there is moral high ground (in this or any other debate), if there is I doubt I can see it from down here. The argument that nothing is ever perfect doesn’t preclude the need to improve anything. No hack, project, theory or society is ever perfect, but that hardly stops people from trying nor condemns us for not achieving perfection.

  13. skr says:

    What a bunch of dicks, asking for a takedown.

  14. miroslava von schlochbaum says:

    heh, i always wondered when this issue would ‘hit’. there’s this issue which is one of linking to unauthorized sources (aggregation); and then there’s the (main) Huffington Post issue of not paying your bloggers (we’ll assume Make™ pays Mr Ragan until we hear otherwise)

    What makes this interesting is that i can see both sides of this issue. It runs the spectrum from “you’re re-publishing my published work without my permission” to “we’re just reporting the news”. Of course, since i’m here, so i appreciate the aggregation service. If i was forced to be an unbiased judge in this case, I’d say this case of aggregation was done more respectfully than the industry’s average. (case dimissed! [wink])

    1. miroslava von schlochbaum says:

      And as an addendum, allow me to congratulate Makeblog/zine for not censoring these comments about this delicate potentially legalistic issue. I know of a closely allied blogsite that would be eliding these comments left and right. We’d never even know this was being discussed. “sunshine is the best disinfectant” etc

      1. sparkmike77 says:

        I completely agree on that point. It is laudable that they would allow these discussions.

        This is a very significant challenge that is not unique the the web, but is certainly more evident. What obligations (ethical, not legal) does a content aggregation service have to the authors of that content? What is promotion and what is exploitation? I think that is a great set of questions to ask the team at Make: and other publications of similar design.

        Make: may be one of the most interesting groups to discuss that with, not just for the broad interests that the team indicates, but also because they deal with so many creative and independent people regularly who also have broad interests. I would really be interested in an article/editorial/commentary.

        1. JonathanG says:

          If you participate in a newsworthy event, what ability should you have to remove any trace of that event from the news? I claim that you should have none. This is based upon the idea that the news doesn’t belong to you, so you should not be able to control it. In a sense, the original site did something newsworthy: they posted information about things of interest to other people. So, following that logic they should have no ability to remove all trace of that event from the news.

          Taking another tack at the same issue, I understand about the damage that is done when you are linked to from a high-profile site, but inherent in the bargain associated with copyright is the idea that you won’t use copyright to unpublish things. That is, once the expression of an idea is published, you shouldn’t be able to withdraw it because copyright was invented is to encourage the public expression of ideas by offering a limited monopoly on that expression.

          If I had any confidence that Nori Lamphere was still following the thread, I’d offer to host a bandwidth-unlimited version of the information, if only so I would have a chance to read it.

          1. sparkmike77 says:

            Which is I believe exactly what should have been done from the beginning.

  15. travis m. says:

    I wonder if adding fiberglass to the mix would enhance its strength, there is a previous article which dealt with glass reinforced concrete, though I have no idea how those two elements would interact in the concrete. It seems to be a good idea in theory, anyway.

    1. sparkmike77 says:

      I think you might get to a point where adding more aggregate to the mix would actually weaken it if there isn’t enough cement to hold it together. I wonder if it might be better for structural strength if you reduced the styrene and substituted glass fibres for part of it. A lot of indusulation is made from glass fibre, so it might not be that big a loss of insulation.

      I’m thinking it’s experiment time… anybody know a god materials engineer with curiosity and a lab?

      1. Jake Spurlock says:

        Love the idea of a “god materials engineer with curiosity and a lab”. Sounds like a fun job, making things like the adamantium, blaze rod, capsidium, and kryptonite…

        1. sparkmike77 says:

          Accidental misspelling creates awesome job description. Why can’t I be that creative on purpose? :)

      2. kevin says:

        It’s not the glass that makes fiberglass insulation insulating, it’s the air, held in a material that keeps it from convecting.
        What you add should depend on the application. Unreinforced concrete has great compressive strength, the Romans used it in structures that have lasted thousands of years. Reinforcement is added to add tensile strength, but it’s a tradeoff in some combination of expense, durability, lower compressive strength, etc. Rebar rusts and destroys it over time for example.

  16. Pellon Auto Centre (@pellonauto) says:

    hi this does sound like an excellent product but what are the temperature variations for really cold countries ?

  17. Concrete Benefits from Bean Bag Fill - - says:

    […] How-To: Styrofoam Concrete […]

  18. pkk says:

    Teacher saved on the blackboard this one use

  19. dperry428 says:

    I’ve had a fish and turtle pond for 10 years now — made from eps concrete. I used regrind eps that is used for concrete block insulation and sold in some home improvement stores. The bottom is regular concrete and the first layer of the sides is eps concrete for insulation. There is mortar layer over the top of the initial eps layer. All rocks are also lightweight concrete, using eps as the aggregate, most of which is broken up packing pieces of eps from computers delivered to the school behind my house. The eps packing was being put into dumpsters for a trip to the landfill, but the maintenance people were more than happy to toss it over my fence for me to use in concrete. Here is my YouTube channel that contains a tutorial on making lightweight faux rock:

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I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

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