Comments from a proponent of OSB/EPS SIPs
1. I would never try to discourage anyone from building a strawbale home if that's what they really want. I've been involved in a number of such projects with Strawbale Walls, and SIP roofs, sometimes with SIP Gable Ends, and a SIP "Top Plate", and once, a SIP floor system. However, if you're "not a fan of the look" then you probably don't want to go this route. I won't even try to get into all of the particulars to consider when you're looking at straw bale construction, there are volumes of material on this topic both in print, and on the internet. I think that the cost is considerably higher than an additional 5% to 10% over conventional construction, if the work is performed by a strawbale pro (including interior and exterior finishes. Of course an "owner/builder" can handle almost any construction project for less....IF...they know what they're doing.
2. SIPs (That's been my business for the past 15 years but I'm not going to use this forum to try to drum up business.....at least not today.........maybe tomorrow) Just plain old OSB/EPS SIPs, good supply source, easy to work with, approved almost everywhere (special certification required in some states and municipalities, eg Oregon, California, Los Angeles)
In regards to SIPs not being "Green". The USGBC LEED program allows points for SIPs (The particular brand of SIPs that I represent has been utilized in connection with numerous LEED certified projects throughout the U.S., many of them at the Platinum Level. There is a US Dept of Energy report that states that " SIPs are at least 66% more energy efficient..." (When compared to conventional framed construction) Of course blown in foam, or cellulose, narrows that difference substantially, but you still have the "thermal short" effect of studs at 16", or 24", on center. It is my contention that if you attempt to meet the same thermal performance of SIPs with a framed system (blown in foam, foam sheathing, staggered studs, etc you're going to approach, or exceed, the coast of SIPs, without the benefit of the interior sheathing, which the drywall, and trim guy, love, for obvious reasons)
Other major benefits of SIPs is the sustainability factor of using less dimensional lumber, and less waste in the landfill.
As far as EPS being a "petroleum product", EPS is over 90% air with pentane, used as a blowing agent during the production process being a very small percentage of the final product. Also, EPS does not contain CFC's, HFC's, or HCFC's.
Major SIP manufacturer list the "green" benefits of their products on their websites.
Now, all of you "pros" out there, understand that I've addressed this over simlpified description of SIPs and EPS to Sespe's questions and comments. I'm sure that he can go back and read previous posts regarding the pros and cons of polyurethane foam vs EPS, etc., OSB skins vs steel vs fiber cement vs magnesium oxide, etc etc, and he can research all of the SIP manufacturers' websites, and google or yahoo all of the key words for vast amounts of information in connection with all of these options. Having said that, I'm just thinking that we don't need to rehash these debates on this thread.
Regarding the comment that SIPs are "Expensive", My contention is that they are competitive with "good quality" conventional construction, in most areas of the US, particularly in areas where there is a need for good thermal performance, and/or better than average structural characteristics.
3. Agriboard: Seems like a good idea, As noted in the original post, they're very heavy, leading to more onsite handling equipment, probably a higher labor cost. Straw, while a natural waste by product, is not as good an insulator as foam, meaning that panels need to be thicker, thus even heavier, and more shipping volume. To the best of my knowledge they're still not approved for use in at least two of the places that I mention earlier in this post.
4. I would think that you could build a nice SIP home in the SW US for $ 200 psf, or a little less. My suggestion is to find a good design/build team that is experienced with SIPs, keep the design simple and straight forward, and the amenities moderate. I'm pretty sure that you're going to get some interest from a number of such parties, and it'll be up to you to determine which of them offers the best combination of products and services to meet your need.
Enjoy the "adventure"!
|