Getting Past the “Sticker Shock” of My SCIP Home

Concrete Home

Vancouver, WA home is built with Structural Concrete Insulated Panels (SCIPs).

By Michael Tausch

As the owner of a “green” home now under construction, I am often asked about the costs of such a project.  For many people the basis for that question has to do with the home’s more glamorous features, what I call the “bling”, meaning features such as solar panels and other alternative energy generating systems or the home’s energy-storage capacity.  Rarely do they ask about the cost of the structure itself, presumably because they assume that a conventionally built structure.  That may or may not be the case. For me, the answer definitely fell within the “may not” category.

The home I’m building in Vancouver, WA, is a concrete structure, more specifically, a “SCIP” home. (“SCIP” is an acronym standing for “Structural Concrete Insulated Panels”). SCIPs consist of panels comprised of foam over a wire mesh which, after being assembled, are covered on both sides with a layer of concrete (more specifically, shotcrete).  The finished SCIPs thus form both the interior and exterior walls of the home.

Building a concrete home with SCIPs

Finding skilled labor to build a SCIPs home can be tricky.

Challenges of Building A SCIP Home

What is it about SCIPs that make them a “green” building choice?  There are many reasons but one of the primary reasons is that their insulation value is considerably higher than that of a wood-framed home.  This is because the foam, though a solid, is comprised primarily of air and air is a good insulator whereas wood is not.

So far, so good.  Whether or not SCIPs are an appropriate and affordable building methodology depends on a number of factors.   Currently, building a SCIP home almost by definition means constructing a custom-built home since “production home” builders (“production homes” are homes found in neighborhoods constructed by one developer or are built on a lot according to the “model” chosen) have, except in a few areas of the country, avoided pretty much any building methodology outside the tried and true.  The advantage of production homes to the homebuyer is that their builders can employ economies of scale and thus price their homes lower.  Unless one lives in an area where SCIP developments have already found a niche, finding a firm to do the job probably means importing a work crew from elsewhere which, of course, means paying for lodging and transportation of multiple persons and can prolong the home assembly process.

The second issue facing the homeowner contemplating SCIP construction is determining the number of panels the home will require.  The answer to that question depends on the configuration and square footage of the home.  SCIPs come in different sizes and are fabricated by different manufacturers, so giving a specific figure for the cost of panels applicable to all homes is not possible.  As an example, however, I can tell the reader that the cost of the panels for my home of approximately 1600 square feet in size ran around $50,000, inclusive of transport.

The Cost is in the Concrete!

Determining the number and cost of panels is only the beginning.  In order to become true “SCIPs”, the “SC” (Structural Concrete) has to be added to the “IP” (Insulated Panels) and this is where the costs can really mount up! The depth of the concrete sheathing depends on the climate area in which the home is located.   Since I live in an area with a temperate climate, 1 ½ inches of concrete on each side was deemed adequate; for those who live in areas susceptible to more temperature extremes such as the heat of summers in Arizona or the frigid temperatures found in the far reaches of Canada, the thickness of the concrete will probably be more.  The differences between depths can be dramatic.  In my case, calculations undertaken to prove compliance with the local energy code showed that if the outside temperature dropped by 50 degrees, the use of the 8 inch thick (5 inches of panel width and 3 inches total of concrete) SCIP walls and roof in conjunction with triple-glazed (paned) windows would result in the interior temperature of the home falling by all of one degree!

That’s impressive – but so is the cost.  The cost of the concrete depends on the home’s square footage, but here I refer not to “square footage” in terms of floor space but to the square footage of the panels.  Warning:  This is where one might feel the need to faint.

My 1600 square foot home has a panel surface area of 14,700 square feet.  That means that 14,700 square feet have to be covered with 1 1/2 inches of concrete. That is a lot of concrete and, at prices ranging from $8 per square foot, a lot of money.  Taking all of these issues into account, it is the cost of the humble, homely (no pun intended) concrete – not the insulated panels themselves, not the energy generating equipment, not any of the other features one typically associates with a green home – that make building with SCIPs a financial challenge for the average homeowner.  To put it bluntly, one could build a conventional home with “green” features such as Energy Star appliances for less than just the cost of the concrete involved in building a SCIP or other type of concrete home.

SCIP Benefits Beyond Energy Savings

As with all things having to do with green construction, however, the higher initial cost of building the home may (and should!) be offset in the long run by lower energy consumption and, hence, lower energy costs.  But there are other considerations.  Concrete homes, for example, are remarkably durable, with a lifespan measurable in centuries rather than decades.  (Well, okay, I don’t know too many 300-year old homeowners, but for those of us concerned about the efficient use of resources, indeed, the very availability of resources in the future, this is a point that can’t be overlooked.)  Concrete homes also require less maintenance than wood framed homes, are resistant to fire, termites, and other such hazards.  They are distinctly quieter than the conventional “stick-built” home which could impact their value in area where traffic or other noise pollution is a factor.

Thus, the decision to “go green” with SCIPs is one with multiple pros and multiple cons.  As for the cons, I think that as the technology proves itself and as it becomes more familiar, costs will come down.  From my own perspective (so far) I stand by my decision to use SCIPS.  Yes, there have been many headaches along the way, but I think most of the anxieties I’ve felt are ones shared by anyone building a home, regardless of the construction methodology.  My intention from the outset was to procure a nice new home for myself, but also make a statement to the community:  It’s time we re-evaluate the way we build our homes.  Given the feedback I’ve received, I think I’ve been successful in that objective.  I also take pride in the fact that this is the first SCIP home in Southwest Washington, which makes those headaches a lot more bearable.

My last bit of advice for the other homeowners considering SCIP construction?  Do your homework.  And have a bottle of smelling salts handy.

Michael Tausch is a retired attorney living in Vancouver, WA.  When not spending money building his home, he devotes his time to numerous environmental causes and writing projects.  You can read more about the construction of  Michael’s home at http://sylvanecohouse.com.

 

10 Responses »

  1. Trish Holder cross-posted this article in my group on LinkedIn. She asked that I repost my comment here…

    Hmm…. quoting from the blog:
    > the cost of the panels for my home of approximately 1600 square feet in size ran around $50,000… the higher initial cost of building the home may (and should!) be offset in the long run by lower energy consumption

    Hard to say what delta-cost is, but however you cut the numbers, there’s no way that system will ever pay for itself based on energy savings. The best way to look at this is to consider the cost of a stick-built home designed to achieve similar performance. Just don’t get taken in by marketing claims about equivalent R-value of mass walls. Exaggerated claims are status quo in ICF and other mass wall distribution channels. There’s a proper way to calculate equivalent R-value but it’s rarely done in practice.

    > Concrete homes also require less maintenance than wood framed homes…

    There’s a thread on this over in Building Science Community IIRC that refutes this notion. Mostly an issue of cost of making various types of upgrades and repairs over the years. It’s seductive to consider concrete structures as being more permanent, but the reality is a bit more complicated. But no doubt a home with concrete walls would be quieter (subject to weakest link, the windows), if you happen to live in a noisy area.

    > My 1600 square foot home has a panel surface area of 14,700 square feet.

    This can’t be correct.

    Other than that, it’s nice to see an article about unconventional construction techniques that at least tries to present a balanced perspective.

  2. Actually, surface area is fairly easy to guess at. If the 1,600 sq ft house has wall 10 feet tall, the surface area will be 16,000 sq ft. Obviously, that’s just an estimate, but it does show that the calculated area of 14,700 is quite reasonable.

    • That does not make any sense at all.

      First, if you multiply square feet (ftxft) with feet (ft) you get cubic feet (ftxftxft) which is the VOLUME of the structure and has nothing to do with the area of the walls, which is sf (ftxft).

      Second, a 20 foot by 80 house with a 10 foot wall has an area of 1600 sf and an exterior wall area of 2000 sf. A 40 foot by 40 house with a 10 foot wall also has an area of 1600 sf but has an exterior wall area of 1600 sf. On the extreme side, but to make the point, a building that is 10 foot by 160 foot also has an area of 1600 sf but an exterior wall area 3400 sf. So obviously the shape of the structure is significant.

      Third, the only way to calculate the square footage of wall is the know the length(s) of the wall and height(s) of the wall. Multiply them together and who will get the area of the wall.

      On the above house he has to do both sides of the wall so he probably had less than 4000 sf of wall surface to apply the concrete to. And this calculates out to about $25 per square foot of wall. A well built 2×6 wall with insulation, or the much better SIP wall, both run around $7 sf installed. Masonry and ICF run about $12 to $15.

      So I hope he has a very nice home.

  3. Wouldn’t the cement be calculated in volume not area?

    Which would be the area L*H of all the wall the, then the W (of the L*H*W volume) would be the width of the spray. The price quoted uses way high, please respond if it was figure right.

  4. Besides the difference in actual wall square footage to actual livable square footage are other factors.
    This house in particular has larger overhangs concrete deccks, water storage and roofs.
    Add to that the areas missing foam or where the design calls for bond beams if you just figured it as you might site unseen you would be in Trouble.
    When dealing with new systems you can get in trouble.
    I do not like to call it new as the first SCIP homes were built in the 60s.
    But it’s new to many and others do not even know what they have till they cut into a SCIP Panel wall.
    I have pictures oh different SCIP homes on pintrest, Disaster Resistant homes.

  5. Concrete is one of the cheapest and most durable construction materials. The trick is to get it to cure in the shape of a house.

    To illustrate, a 40′ x 40′ x 8′ (1600 sf) cottage made from a concrete shell 4″ thick would require:
    [] 4 walls, 40 x 8 x .33, (15.64 cy)
    [] 2 slabs, 40 x 40 x .33, floor and roof deck (39.11 cy)
    54.75 cubic yards of concrete

    If concrete cost $100 per cubic yard, that comes to $5475.55 for the concrete shell.
    {Of course, we can modify this basic recipe … split the 4″ concrete into two 2″ skins surrounding an insulation core… SCIP}

    Adding stories, saves on materials, too. You can omit one slab, cutting 33% .
    54.75 + 35.20 (2nd story) + 35.20 (3rd story) = 125.05 cy, or roughly $12,505 for 4800 sf house (with an optional 1600 sf roof deck).

    • Yes and I know of houses built in the 30′s and 40′s of concrete. One in particular had passive air conditioning (yes, completely effective within reason and totally free), and is in Florida where AC IS A REQUIREMENT of life.

      The real problem is that concrete of any type is porous and allows water intrusion. Where concrete exterior walls might make sense in Nevada or possibly Utah or Arizona, in a humid climate one might be asking for trouble. Eventually water makes it through the concrete and then attacks the steel. The concrete will may times flake or even explode into pieces when this happens.

      There are many ideologies about sips of various kinds. I have my preference.

      As far as this article, the author never told us his foam thickness and actual R or U values in real world testing. Here in FL damn near every spec home has to have testing now. We have to meet the energy requirements as well as many other codes. I wish he had told us more….as in he used say 6 in (specify type) foam and resulted in an achieved R36 system.

  6. Just to chime in here…I know it’s a little late. I’m currently calculating the cost of a SCIP home in Ecuador.
    You can’t just figure it by volume… Remember you are “finishing” both sides of the panel. e.g. You’re figuring for both the interior and exterior of each wall, not 1sf at 3″ but 2sf at 1.5″. Considering it that way and assuming a structure that is 20′x20′ with 10′walls and a traditional roof you will have 80 linear feet of wall by 10′high= 800sf. You THEN MULTIPLY THIS AREA BY TWO. Because you have exterior and interior surfaces to consider. You now have 1600sf of wall to “finish” with 1.5″ of concrete on a home that only has 400sf of floor space..More specifically “shotcrete” which is not simply priced by the yard, nor dumped on to the ground out of the back of a cement truck, but the cost of labor must always be included in the price of shotcrete, making it much more expensive per sf than just poured concrete.

  7. I love number comparisons, rarely do they reflect where I build
    When comparing systems per foot is the fact that SIP and ICF still have considerable cost to cover the system so it is finished.
    .
    Also a big misconception is the SCIP system only works in _ _ _ _ _ location.

    SCIP Building Systems on Facebook I show factories around the world. I do not have all the factories I only list about 70.
    Currently two or three factories in the USA for residential building, a few for commercial and mining.
    The first panels were built in the late 60s in California. First patent was give in 68 I believe.
    Another factor is EPS foam is a better insulator than commonly understood. The thermal conductivity diminishes rapidly after 2″ giving better thermal properties.

  8. Another consideration is the amount of fallout that WILL happen on overhead spraying (re-purposing the excessive waste is highly recommended). Also, the thickness of concrete on the roof will vary based on the desired slope, thereby increasing the amount of materials. Lastly, building a SCIP home in the NW is challenging for other reasons: weather/climate and trees/debris. Keep it in a dry climate and you’ll be happier.

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