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Alternative to Double-Stud and Cellulose Wall Assembly

Donald_D | Posted in General Questions on

Hi everyone,

We’re in the design phase of an energy efficient (almost passive house) home and this metal stud/EPS SIC panel system came up as an alternative for double stud – Cellulose- wall assembly. We would consider this for cost savings, with the current high lumber prices and will save on labour as well.

SI Construction – Structural Insulated Construction Systems (

Footprint of the house is approx 800sqft – 3 levels (basement-main and upper) 2,400sqft total.

We live just North of Edmonton AB Canada, so winters are cold. We’re aiming for R50 walls.  Roof would be std trusses and blown in cellulose. R80-ish.

What options would be best for Water, Air and Vapor barrier?

Any feedback is much appreciated


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  1. GBA Editor
    Kiley Jacques | | #1

    My guess is that seasoned builders will say you would be hard-pressed to compete with a double-stud wall /cellulose insulation assembly, no matter the suggested savings, but I'm giving your question a bump in hopes that others will chime in.

  2. ohioandy | | #2

    This panel system strikes me as a "boutique" solution in the sense that despite the website's claims that no special skills or tools are required, its uniqueness represents an uphill battle unless you've got a gung-ho builder willing to try new things. I've been trying to work out whether it has any inherent advantages over, say, SIP construction, but it's hard to guess how things would play out on the jobsite. There are obvious questions, like how is airtightness best achieved--with interior drywall or exterior sheathing? What about all the structural loads, particularly racking? I wonder if by the time one assembles a proper structure, you've got as much if not more work than any other system. In the end, we should also vigorously interrogate any system that relies 100% on chemical-based insulation when more green alternatives are readily available. (This from a guy living in a SIP house.)

    1. MarkSICS | | #4

      Hi Andy;
      I'm the owner of S I Construction Systems, an original developer of and the only manufacturer of the Polycore system being discussed. I appreciate your comments, they are interesting and quite applicable to many of the new systems coming to market these days. However, I'd like to clarify and in some cases present a different take on things.
      I started this product in 2003, at which time it was "boutique" and yes, it was an uphill battle that needed gung-ho builders to get on board. The good news is that those builders were out there, and in 17 years they let us manufacture over 1400 projects. The best news is that we listened to their feedback, took their field advice, visited their job sites, and spent the first decade and a half making the product and the systems better for the user in every way we could. That process gave us and established the inherent advantages I think you're looking for. Some of those are:
      - every system is engineered and stamped for design and structure to cover loading, racking, and optimal use of steel for cost and structural efficiency
      - 100% pre fabrication of every piece of the system in the plant, its a field assembly job with all pieces already the right size and shape, with the right structure in the right place
      - No cranes, no special equipment or tools. The level of pre-make in our factory means you really can put it together at the site with nothing more complicated than cordless power tools
      - Most sections can be hand carried by a single worker, and in fact we've never made one that couldn't be carried by two
      - Assembly time really is just 1-2 days per level, crew of three. Previous Polycore experience gets you to the one day timeline, newbie crews can still do it in two
      - The system is a lot less work than other systems, so much so that over 1000 of those 1400 projects were built by the homeowners themselves. All skill levels. We provide on site training whenever needed, a couple of hours does it every time, and engineer inspection and sign off to confirm it's done the way it should be
      - Air tightness is achieved simply by doing it right. Caulking or foaming joints, standard poly, taping and detailing fenestrations. Our first below 0.6 ACH was achieved in 2008, with many since that time and the lowest record was at 0.29 last summer.
      There is a lot more to our system, we try and summarize the difference from other methods, systems, and products as simply as possible. One line.

      Faster. Better. Easier. For less.

      Polycore is actively sought out, chosen for, and accepted for Passive House, Net Zero, and high efficiency builds. Zero thermal bridging, selectable insulation values, proven low ACH results. We're trying to get more information out there to show all that, but without a war chest for marketing it just takes a lot of time to get there. I'm better in a conversation than in detailed social media marketing and information, so I welcome calls from anyone from anywhere looking for details anytime. Discussions are good, my direct contact info is on our website for anyone who wants to chat. Give me a call.
      Oh, and I'm a life believer in EPS as the best insulation material / value out there. Its industry recognized as the best "R per $" value insulation. It doesn't have HFC and ozone depleting foaming agents like XPS. It uses a bare fraction of the energy input required to melt sand and glass into fluffy pink or melt rock into wool. A single Polycore foundation and no-concrete floor package removes multiple truckloads of concrete from the building program, now that's an environmental plus. Less concrete is just good. And using EPS instead of lumber keeps tree's in the ground where they can continue to remove carbon and purify air. Lumber doesn't work as well for the environment as trees, and all that "sequestered carbon" in lumber still gets released when wood houses are torn down in 30 or 40 years. We design with the expectation that Polycore envelopes should last a 100 years.
      Yes, EPS is a "100% chemical-based insulation". But it's pure, a one ingredient plastic. It's 100% recyclable, always has been, and can still be recycled in 100 years. I've actively recycled EPS in every manufacturing operation Polycore has ever been made in. I estimate in 17 years manufacturing 1400 projects I've sent less EPS to landfill than a single family would have sent over the same time. Polycore is clean at the construction site as well, scrap from a full system install wouldn't fully fill a garbage bag. And, as the kicker, we'll take that garbage bag back, recycle the steel and EPS in it, and then recycle the bag.
      I like EPS, and I like Polycore. I believe in what I'm doing with it. I think it's a great choice for builders, a great choice for home owners, and a great choice for the environment. I hope you, and Donald_D, and others that get to know it think its a great choice as well.
      Take care and stay safe in these crazy times, and Have a Great Day!
      Mark Cunningham 780-450-2584

  3. charlie_sullivan | | #3

    I have trouble imagining that this will really be more cost effective but if you have solid quotes on that, maybe it is.

    As far as performance, I went to their residential wall section and saw a downloads tab where I hoped I would find more, and all I found was

    "I am text block. Click edit button to change this text. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo."

    Hopefully they have real documentation hiding somewhere?

  4. MarkSICS | | #5

    Apologies for our website links, had some site developer issues and we are working on finding a new provider to finish things off. I posted a lengthy reply above in this same conversation that may provide some information at the moment, we can also provide budget and quote pricing on on any set of drawings to show the performance and cost effectiveness that Polycore does bring to a project. I can link you to our information folders directly, reach out to me at [email protected], and we should have those website links working by end of the month. Thanks!
    Mark Cunningham

  5. MarkSICS | | #6

    I've posted some information in this conversation as replies to some of the other comments, a bit wordy but hey, I believe in the product I manufacture. I see you're near Edmonton, we have a showroom in our premise with full size displays perhaps you can come by to see the systems for questions and discussions. It is a great choice for Passive and Net Zero buildings, I hope we can get a chance to show you why. Thanks!
    Mark Cunningham 780-450-2584

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