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dcook4
Registered Users
Posts:17
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| 02/21/2008 7:42 PM |
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| I was wondering if anybody knew which is a better choice to build with keeping in mind cost, R-value, labor and availability. Also if anybody knows of any SIP builders/suppliers in Manitoba or surrounding area? |
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Dick Mills
Registered Users
Posts:123
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| 02/21/2008 9:58 PM |
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dcook4,
Unfortunately, there are usually no clear-cut best choices. Obviously, if there were best choices, then there would be no other options available. And, if anyone here tells you otherwise, you should probably suspect their motives (they are probably trying to sell you something).
And, it usually comes down to personal decisions that relate directly to your wants and needs. One tool that I have found that is helpful in making these types of decisions is a Decision Matrix. While they are by no means perfect, they can help to point out obvious choices (if they exist for your personal situation). Wikipedia has a very short article that will give you a basic understanding of utilizing a decision matrix, but most of the work involved is accurately assessing the various options with regard to your situation.
http://en.wikipedia.org/wiki/Decision_Matrix
Dick Mills |
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olpjeb
Registered Users
Posts:55
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| 02/22/2008 8:57 PM |
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dcook4 -
I built with polyurethane SIPS. I used 4 1/2" panels for walls (R-28) and 6 1/2" panels for the roof (R-40). Here are the points I saw about EPS vs PU since I went through some of decision thought process with both materials.
1) EPS is probably a bit cheaper(though not by much)
2) PU panels will be smaller for the same EPS R value (less shipping and less bulky)
3) PU panels require electrical boxes to be foamed in place during manufacturing
4) EPS has a bit more flexibility with electrical since chases are pre-routed. Adding a box as an afterthought is almost impossible with PU
5) PU has a better fire rating. It will not melt like EPS at a lower temperature. PU is a thermoset plastic.
6) The PU is directly bonded to the panel substrate, so there is no concern for a glue interface like with EPS. I would say less risk of delamination with PU.
7) There is a risk (probably VERY SMALL) with PU that the foam will not fill the cavity and therefore you end-up with a void-filled panel.
8) PU has a much lower vapor permeability than EPS.
You will likely not go wrong whichever path you decide. Be sure to select a good manufacturing company and a knowledgeable installer. Check your panel drawings MULTIPLE times before they get fabricated. Demand that the manufacturer give you EVERY dimension before giving the "GO".
All the best to you. |
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lkazanov2
Registered Users
Posts:104
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| 02/22/2008 9:51 PM |
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OLPJEB,
Excellent summary, I think the biggest factor of PU vs EPS is that the PU is the adhesive itself and less concern for delamination. EPS is much more workable (cuts with hot knife). For an absolutely set and thought out design I think PU is better. EPS for the field "flexibility." |
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trigem1
Registered Users
Posts:47
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| 02/23/2008 2:07 PM |
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dcook4
Both are excellent products, both have their pros and cons and both are way better than stick built. The only drawbacks with PU, in my opinion, is that the PU panels are only available in four ft widths. To me, it's just faster and easier to put up one 8 ft by 14 ft long panel than four panels with more nailing, more glueing, more splines and more seams. The other drawback with PU panels is that for the same R-value, PU panels are somewhat more expensive. On the other hand, for a DIY'er or a small crew, the smaller panels may make sense.
Steve
GrandCountySIPs.com |
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Alton
Registered Users
Posts:244
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| 02/23/2008 2:45 PM |
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Some steel/polyurethane panels are 3" thick by 2' wide by 50' long.
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cmkavala
Registered Users
Posts:702
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| 02/23/2008 3:10 PM |
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| And some EPS /steel SIPs are 45-1/2" wide by 53ft. long , available in 4", 6" 8" & 12" thicknesses |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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GeorgiaTom
Registered Users
Posts:114
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| 02/23/2008 3:12 PM |
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| Can someone explain about PU and shrinkage with age? |
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bpickartz
Registered Users
Posts:5
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| 03/01/2008 12:27 PM |
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| We've used both and made a decision to offer only polyurethane. We've used multiple companies and have been satisfied with most (one had internal issues that were later resolved we're told). You can get Urethane panels in widths up to 8' and lengths up to 24'. We've added boxes after the fact when clients changed their mind and had no problem with it. It can't be "burned" out with a hot knife and I see that as a plus, but it can be routed out and cut. We've used these panels for over ten years and don't make any excuses when asked why we don't use a cheaper panel. I do agree that whichever you use, you are ahead of the game in building a more energy efficient, sustainable home. We've had no shrinkage in our urethane as far as we know. There are statistics out there about a loss of R-value over time, but that is minimal and most producers use the diminished figure in their literature. |
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Paulcf
Registered Users
Posts:17
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| 03/01/2008 1:01 PM |
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I spent 7 years to investigate ALL manner of building an energy efficient and tight house. Energy creation was not the area to focus on, energy conservation was. After my 7 years, I became a fabricator and distributor for polyurethane SIPs. The advantages over EPS or polystyrene are many and I have all the research. EPS is cost effective but half the R value of PU for about the same thickness. There is a reason why people buy a Lexus or a Kia. Both do the same thing, but the experience and results are very different. We keep to 4X8 or 4X12 and can make any length desired. Besides we can eliminate costs by having 2 guys easily move a 130lb SIP panel. But a panel 8X12 needs a lift/expense. We have developed a vibrating cutter tool that easily cuts out foam if the client wants to enlargen a window opening on site. We easily router out holes for electrical boxes anytime/anywhere and easily drill the vertical chaseway for the wires, in the field. We of course put vertical chaseways in the SIPs in our plant based on the blueprints.
Our SIPs are injected with 2,000 PSI and the computer knows exactly how much liquid to inject to expand. So voids are impossible and we've never had one. I have tons of material on the factual chemical differences between the foams.
It was nice to be totally agnostic to this industry and to go into it asking "why" all the time. I learned a lot and thus not having any prejudices made the facts stand out clearly. We win business all the time from EPS projects due to our product, quality and guarantees.
Build with SIPs is NEVER a wrong decision no matter what they have in them...stick building is so 19th century! |
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Alton
Registered Users
Posts:244
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| 03/01/2008 2:07 PM |
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Paulcf,
Do you have a web site? Where are you located? Here is my e-mail address if you do not want to answer in this forum:
Alton (at) Auburn (dot) Edu
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Paulcf
Registered Users
Posts:17
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| 03/02/2008 6:18 PM |
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Hi Alton, I'll reply via email.
Someone called Jennifer sent me a response but I can't find her email address...please reply and include your email address please. Thanks. Paul. |
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