Q: I came across your site while looking for alternatives for exterior wall finishes on a SIP's house in Troy, NY -- before you go, "Ugh, SIPS!" the project is for low-income housing intended to be built with no skill or low skill labor. We are still experimenting. Originally, the designer called for T-1-11 to go on the outside. There have got to be better solutions that we can afford! Any ideas? Do you supply products yourselves?

A: (Kelly) We don't supply any products ourselves, only information. Depending on available resources, you might consider siding the building with the rounded slabs that are often left over from milling trees; this would produce a log cabin appearance. Another possibility might be to plaster the outside with stabilized adobe, to give it a very natural appearance.

Q: I acquired a series of foam panels I would like to construct a structure with. They are similar to SIP panels, but the outside is thin sheet aluminum. The panels interlock and are held together with sheet metal screws. I believe they are actually freezer/refer panels manufactured by Hussman. My question is who can I work with to design the structure and create some plans I can submit for a building permit?

A: (Kelly) I have just been assembling a new website www.dreamgreenhomes.com, which is devoted to providing sustainable house plans designed by a variety of architects and designers. There are few house plans presented there that are adaptable to SIP construction. If you want to work on a new custom design, let me know, and I can refer you directly to one of the architects.

Q: We live in an 100 yr old cottage that is about 900sf.  Our addition will be approximately 25x20, with a basement below, and connected to the existing cottage by a 8x16 foot transitional area with crawlspace below.  I HATE being cold, and SIPs seem to offer excellent insulation, plus other efficiencies: less timber used, easier/faster construction. We are interested in Hardiboard siding, but I infer from Mr. Frechette's  Q&A's that attaching siding to SIPs could be a problem.  My worry is that, since we are connecting the addition to an older house, that if the plans aren't perfect, there is no wiggle room with an SIP-constructed addition, to make those inevitably necessary tweaks to the project. Help!!!

A: (Kelly) As for attaching hardiboard siding to SIPs, I wouldn't expect this to be a problem. It might be that using deck screws instead of nails to attach the siding would be advised to assure a strong bond with the SIP's OSB skin. Your other concern about there being no wiggle room I suspect would not really end up being a problem. With modern foaming insulation products to fill in any gaps, and the fact that SIPs are inherently dimensionally very stable, your construction should end up seamless in the end.

Q and A (Kelly): I want to build a house that utilizes the simplest approach, as with SIPs. Although I read the technical data I do not totally accept the data on the SIPs. As well, I have issues about OSB and how does the panel breath.

As far as I know these panels do not breath.

Where does the moisture dissipate to with a closed cell panel? What keeps the OSB from deteriorating?

Interior moisture will need to be vented somehow, so this would need to be incorporated into the building design.

Is the panel really a strong I-beam capable of withstanding Texas high wind thunder storms?

My understanding is that these panels are amazingly strong. Obviously a significant system for tying the roof and wall panels together and to the foundation would be essential.

Q: I am very interested in SIPS construction methods. A gentleman, "Hoot" Haddock, builds SIPS at his plant in Florence, about 8 miles from our lot. Everything I read about SIPS discusses OSB on each side. Mr. Haddock's use a cement board cover on each side. Is he just going in a different direction or do you see problems with the cement board.

A: (Kelly) OSB is common with SIPs because it is cheap and it does the job of providing sufficient shear strength to withstand all stresses that the SIP might encounter in its structural life. The question is: does the cement board  you describe also serve this function adequately? I don't know the answer to this, but I would hope that the manufacturer does. I presume he has performed tests that would prove this. Off the top of my head, I would say that the cement board that I am familiar with would not have the shear strength/weight ratio that OSB would have...so weight might also become a factor with this product. I would be cautious, and make sure that adequate testing has been done to your satisfaction. The cement board would have the advantage that it is not vulnerable rot, which cannot be said of OSB.

C: I would also like your comments on the other plans we have for the house. It will have a walkout basement, will use steel framing for the interior walls, and 90+ gas furnace & high efficiency conventional a/c. We will use high efficiency windows and doors. Should we use SIPS panels for the basement walls or use formed/poured concrete (as we use here in Ohio). The house is 2200 to 2400 sf (covenant requirements) and we know it is too big for two people but we expect high visitation rates from friends and family.

A: (Kelly) This is where engineering data related to the SIPs in question would be essential. Can they withstand the vertical load in question? If they can, the added insulation of the SIPs over a conventional poured concrete foundation would be an advantage. Also, I wouldn't even consider SIPs with OSB in such an application, whereas the cement-board ones might work. I think you need some expert engineering advice.

Q & A (Kelly): What are the cons of sip panels?

From a sustainable point of view, the cons of SIPs are that they are rather industrial in nature, so there is a lot of embodied energy in their manufacture and and distribution.

We have a local builder who is gentle in intent toward the environment and can build with sips, offering aluminum sandwich foam. What are the off-gassing issues?

I am not familiar with the aluminum sandwich, but I wouldn't expect much offgassing from these, since the aluminum would seal the foam core; also, my understanding is that there is actually little offgassing from the EPS, if this is what the core is made from.

And then pests-rodents?

I do know that rodents and insects can happily burrow into soft foam products, so it would be important to make sure that they don't have access to do this. It is especially difficult to keep ants and other small insects from doing this, so it may be necessary to deter them with some sort of pesticide if they become prevalent.

How do sips compare with aac's?

AAC is basically a foamed masonry product, so it is inherently much more durable and impervious to the above hazards. It is also fireproof. AAC would not likely provide as much insulation per inch, but this can be overcome by using thicker walls. AAC panels can theoretically be used in similar ways to SIP's, although they would be much heavier and may need special equipment to assemble them. As far as I know there is no off-gassing issue with AAC.

Q: I would like to get your input on our company, it's Techbuilt systems inc. you can get the most information at Techbuilt.com. We have been doing this, with a lot of advancements, for over 20+ years. Having your experience I would love to get your honest thoughts.

A: A brief overview of your systems suggest that you manufacture fairly standard SIPs, using either sheet steel or OSB skins with EPS cores, and that you also use thin gauge steel structural components where necessary. My general comment about SIPs can be seen here. When analyzed from a standpoint of embodied energy, SIPs obviously do represent a fair amount energy both in their manufacture and and their transportation to the construction site. From this standpoint they could never be as "green" as other natural materials such as adobe or earthbags filled with soil. But because they do provide excellent insulation and do reduce the reliance on forest products to some extent, they could be considered moderately green.

C: Thank you for the input, actually we use 18 gauge steel tube (galvanized and welded) on the out side and the inside of our panel, creating a thermal break between the outside and the inside.  There is 1 1/2" 18 gauge angle that connects the  the top and bottom.  There is no plywood or harmful glues in our structures.   I believe we are the only system to use 18 gauge steel tube and that is standard.  We can modify our system to go above 3 story's (above grade) by increasing the gauge of steel.  The steel is 2 ft. on center along the wall (inside and out) and 4 tubes at each corner 8" and 12" from edge.  Our system is documented at 90+ efficient and we won the governor's award in ohio with the most efficient house ever measured in ohio (94 %).   Our roofs are utilizing the same galvanized steel but increasing size and gauge depending on spans.  We also offer on onguard material in our foam that will not allow rodents to burrow or nest in the foam. 

Like you said, the EPS manufacturing has to be addressed.  That is a great point that EPS is not as green as the adobe homes, but I don't know that people are open minded enough to see their benefits, especially, mortgage companies (they're not at all green).  Our mission is to quietly reduce fossil fuel consumption by 75% by building structures that just don't need all that fuel. I love solar and am working on two projects in  long island that will utilize it.  Trust me we struggle financially because we put all the steel in and buy foam that is the best quality we can get.  We have and are trying to go to a soy insulation or there is a gentleman in Idaho who is trying to recycle garbage into an EPS type material.  We told him, we'll be his guinea pig.  We're trying.  Go to a website called sunearth.net; it's for an architect firm called Watrous Associates, read their vision statement.  Sounded great to me.

R: I fully appreciate your interest in providing a reliable building system that appeals to the mainstream public and lending institutions, while creating building shells that are very energy efficient. Your system, when coupled with good passive solar heating and cooling design, could go a long way toward diminishing fuel consumption. I applaud any efforts you make toward utilizing renewable and non-polluting components.

C: Many of the LEED certified architects have not given  a whole lot of consideration to the overall envelope.  It almost seems, if you can't see it you don't need it.  Also I just read an article that will give more points than before to wood.  I hope they are not considering some of the slow growth/rare woods.  I hope the powers that be, will keep raising the bar and not lowering expectations to satisfy the wood councils.  Realistically they have a lot of money on the line, and often times policy is not written by those that are right, but who "invests" the most money.   I don't want to make this political, I just want more people like you.

Q: I am building a home in Kalamazoo, MI very shortly and am building as green as my budget will allow. The house will be a 2 story walkout with the MBR above the 3-car garage. So the house is pretty compact on other words. Do you recommend I use SIP's or ICF's? I'm pretty confused as to the very best for my area. I got to see a Polysteel addition going up this morning and it seemed very cool - but will it be too cold in the middle of January???

A: (Kelly) I think that you would ultimately have better control over the thermal characteristics of your home if you choose a highly insulating SIP system for the shell, use a good passive solar design for the home (see www.dreamgreenhomes.com for some ideas about this), and incorporate sufficient thermal  mass material within the shell. The ICF manufacturers try to convince you that their system will incorporate both insulation and thermal mass, and to some extent this is true, but the technology compromises both aspects in the end.

Q: For a passive solar house in a cold climate, which is better, SIP's or ICF's? If ICF's aren't good because they don't have thermal mass on the inside, are SIP's better, because they don't have thermal mass on the inside either, do they?

A: (Kelly) You are right that SIPs don't have any thermal mass associated with them, but they generally provide better insulation (depending on their thickness) and don't require all of that cement and steel...and thermal mass can always be added to the interior of any house in various ways.

Q: What about the system made by kokoonhomes.com? They look easy to assemble, any thoughts?

A: (Kelly) These are basically what are called structural insulated panels (or SIPs) that are made with steel frames and foam insulation. In some ways steel is more sustainable than wood these days, since much of the steel used is recycled. They say the walls provide R-19, which is standard for 6" fiberglass-insulated walls, and is adequate, but not great. For a manufactured system that will last a long time and is easy to erect, this system has some advantages. One consideration, though, is that these apppear to be manufactured in Georgia, so unless you live nearby, the shipping is going to be expensive and costly to the environment.