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CHL
New Member
Posts:29
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| 17 Jan 2009 03:07 PM |
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Thanks for keeping it classy, SteelSipMan.
Very impressive Chris. For a horizontal span of 19ft do you have to reinforce the inside of your panel with anything or is it 100% EPS? What density EPS are you using? I know the tensile strength of steel is very strong and I'm sure that's what makes your panels so strong in this dimension. Again, very impressive. |
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SimonD
Basic Member
Posts:113
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| 17 Jan 2009 04:05 PM |
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Although this thread has gotten off topic a little, I will back Chris K. up, and say that 19ft is a workable panel span for a 6" x 26ga. steel x 1lb. density EPS panel used as a roof panel in certain regions of the US. As a designer down here in Florida most of the designs I've done have been in 120mph wind speed zones and 19ft is a workable horiz. clearspan up to a pitch of about 5 in 12.
I think that building is and should be a regional practice where the materials and methods evolve to suit the climate and conditions of the region. The use and availability of different panel types maybe evolving in the same way. Down here in the hot and humid southeast metal sips seem to be getting a foothold, because they address and solve so many of the issues we face down here. We don't need the highest R-values, so EPS foam works and is what is commonly available. Moisture resistant material is a high priority down here and that's where corrosion resistant sheet metal works and is commonly available. Metal roofing has a long history down here, so the use of a metal skinned sip is a natural progression that evolves out of the building culture down here. I think there is a best panel type for each region of the US based on cilmate conditions, regional availabity of materials and regionally established building practices. So there is no ultimately best panel type, but there is a best panel type for a specific region. |
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| Building Designer<br>PANELfusion, LLC, Tampa, FL<br>simon@panelfusion(dot com)<br>"Metal SIP Advocate" |
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SimonD
Basic Member
Posts:113
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| 17 Jan 2009 06:20 PM |
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The interlocking metal sips Chris K. and I are refering to achieve that span with no additional reinforcement. Just the steel skin, eps core and the male female interlock.
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| Building Designer<br>PANELfusion, LLC, Tampa, FL<br>simon@panelfusion(dot com)<br>"Metal SIP Advocate" |
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Dick Mills
Basic Member
Posts:217
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| 17 Jan 2009 07:31 PM |
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A 19 foot span must put a lot of stress on the fasteners at the top and bottom. I assume these are roof panels with a 40 pound load or there about. Each foot would need to support 760 (or at least half of that) pounds of load before factoring in wind and other loads. Can a 26 gauge skin support that? |
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cmkavala
Veteran Member
Posts:4327
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| 17 Jan 2009 10:00 PM |
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SimonD;
our core is 1.25 lb. density
Dick;
The stress is on pullout/pull thru and are worse on OSB skins, we basically use the same fasteners that the OSB guys use only we also use 1-1/2" fender washers.
the loads are transfered thru the core to the skin if the maximum load is imposed.
yes, panels will support and are engineered with a safety factor of 2.5 |
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| Chris Kavala<br>[email protected]<br>1-877-321-SIPS<br /> |
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SimonD
Basic Member
Posts:113
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| 18 Jan 2009 01:00 AM |
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Chris K,
I've heard that 1.25 lb in density is the 'magic number' to achieve the best strength to weight ratio in a metal sip panel, so that's great, your not skimping on the foam density like some other companies do.
As Chris K says, in metal sip construction large washers are put under the heads of the sip screws to provide increased resistance to pull-thru and if necessary the on center spacing of the screws is reduced. |
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| Building Designer<br>PANELfusion, LLC, Tampa, FL<br>simon@panelfusion(dot com)<br>"Metal SIP Advocate" |
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RasThavas
New Member
Posts:5
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| 18 Jan 2009 07:11 PM |
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Thanks for everyone's replies. If you wish to reply further about what you may know about PU delamination (or lack thereof) please do. |
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Rsipgeo
Basic Member
Posts:104
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| 28 Jan 2009 02:14 PM |
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I think it bears repeating that span length has nothing to do with delaminating. It depends on thickness. Eps panels are thicker than PU panels generally. |
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cmkavala
Veteran Member
Posts:4327
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| 28 Jan 2009 02:41 PM |
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Posted By Rsipgeo on 01/28/2009 2:14 PM
I think it bears repeating that span length has nothing to do with delaminating. It depends on thickness. Eps panels are thicker than PU panels generally. Rsipgeo; not sure what you mean by that, but certainly overspanning will delaminate by shearing foam from skin or will buckle the panel most PU/ steel panels have much sorter span capabilities compared to the same thickness EPS /steel panel |
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| Chris Kavala<br>[email protected]<br>1-877-321-SIPS<br /> |
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CHL
New Member
Posts:29
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| 29 Jan 2009 11:15 AM |
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The last shot in the note above doesn't make much sense. Whether the foam core (or web) of a panel is PU or EPS or XPS, the span capabilities of a panel are driven by the siding material (flange), and primarily the bottom one. The modulus of elasticity and tensile strength of steel is orders of magnitude greater than that of foam so the type of foam core bears little significance if the thickness is the same. The thickness of the foam core - regardless of type (of the foams under discussion) - will increase a panel's span length.
There are polyurethane panel companies that are happy to make you a steel SIP that will span similar distances as an EPS panel of similar thickness. Also some companies out there will give you steel siding on the interior side for span distance and OSB (or similar) siding on the exterior for ease of roof installation. Many opportunities out there. |
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SimonD
Basic Member
Posts:113
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| 29 Jan 2009 04:30 PM |
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Foam density plays a part too. I say that the higher the density of the foam core of a SIP wether it is PU or EPS, the less likely it is to delaminate, not from poor bonding of skin to foam core, but from the shearing away of the very top surface of the foam from itself if overloaded.
Overloaded shorter spanning panels (8'-10') are more likely to delaminate than overloaded longer spanning panels (17'-19') because of the way the foam core is exploited by the forces of shear and bending. Short things can shear, long things mostly bend. |
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| Building Designer<br>PANELfusion, LLC, Tampa, FL<br>simon@panelfusion(dot com)<br>"Metal SIP Advocate" |
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SimonD
Basic Member
Posts:113
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| 29 Jan 2009 04:50 PM |
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A simple field test to check the general quality of the lamination of a companies SIP is to get hold of a peice of scrap and tear the skin off of the foam core. Then look at the underside of the skin. It should be completely covered in foam with no skin showing. With a poor lamination the underside of the skin will have clear areas or streaks where the foam didn't bond. If for some reason the SIP tears almost equaly in half down the center of the foam core which is unusual, then the density of the foam core is in question. |
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| Building Designer<br>PANELfusion, LLC, Tampa, FL<br>simon@panelfusion(dot com)<br>"Metal SIP Advocate" |
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cmkavala
Veteran Member
Posts:4327
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| 30 Jan 2009 08:34 AM |
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Posted By CHL on 01/29/2009 11:15 AM
There are polyurethane panel companies that are happy to make you a steel SIP that will span similar distances as an EPS panel of similar thickness.
We have never found one with equivelent span capabilities, if there is one ......Name some please |
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| Chris Kavala<br>[email protected]<br>1-877-321-SIPS<br /> |
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kevinbourland
New Member
Posts:31
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| 11 Aug 2009 08:50 PM |
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My Polyurethane panels "spooned out", bowed, or whatever you call it, the first Winter, over 1/2". Tearing sheetrock from corners, pulling away from wall.....countertop etcc.....Then goes back in During Summer!!!
Ya sounds like a great Product!!!!! |
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| Kevin |
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CHL
New Member
Posts:29
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| 12 Aug 2009 08:29 AM |
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I'm sorry you've had a bad experience, Kevin. PUR foam, just like EPS foam, is a cast or molded foam and both products are well known to be dimensionally stable after manufacturing assuming a proper process has been followed. One major difference between the two is while many EPS manufacturers are purchasing bun stock from a major supplier and then gluing siding to the bun stock (very often using polyurethane resin glues), most (not all) PUR manufacturers are blending and injecting PUR foam in their factories. If their mix is off, you can get a defective panel. I have been around a lot of both types of manufacturers and for 99+% of the time they all do a great job as their companies depend on them producing a quality product.
It is interesting, however, that you note that the panel is flexing due to seasonal changes. This sounds entirely to me as if you have either a varying coefficient of expansion between one side of the panel and the other (possible siding material effect), just like a thermocouple or dielectric material. You may very well have things going on in your wall (probably on the outside) that you do not know about. The thing about both PUR and EPS foam is that they are dimensionally stable across a VERY WIDE RANGE of temperatures and unless you have contaminants in the foam you absolutely should not see dimensional drift or creep in the foam due to temperature variations.
Any other engineers/scientists out there have thoughts on this? |
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ecobuilder
Basic Member
Posts:102
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| 19 Aug 2009 05:34 PM |
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Rasthavas,
I just recently worked on a PU SIP's house that did have delamination problems. Although this was probably more due to the moss growing on the roof than the product it'self. The roofing shingles were completely covered with moss, making the OSB saturated. When I stripped of the roofing shingles some of the OSB came with it. Not only in the areas where the roof was wet, but also spanning out from this area. This was a 25 year old house that may have had something to do with it. The fix, while not simple wasn't really that complicated either. We stripped back all of the loose OSB, applied new plywood, covered with tar paper and then built a cold roofing system on top of this, screwing 2x4's on the flat threw the SIP's into the beams. At location were there were no beams, we simply screwed from the inside out to secure the 2x's. The panels themselves suffered no structural problems, but if the spans were not so short it may have been. Also these SIP's houses built back in the 80's didn't have any type of air exchange system, making me wonder if this may have had something to do with it also. This is my only experience with SIP's delamination but I have only been working with them for 15 years or so, maybe some of the other more experienced people on this site could elaborate on actual experiences with this problem rather than debate which product is better? As for me, I don't sell SIP's but I do install them and improper installation may also have caused some of the problem. Also the OSB used back then is not the same as it is today, and the glues are much better as well. If done correctly I don't think you will ever have to worry about delamination. (rare occurance mostly due to neglect of roof).
Tom Pittsley
[email protected]
www.eebt.org |
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| "Don't be afraid to go out on a limb. That's where the fruit is." Jackson Brown |
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RasThavas
New Member
Posts:5
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| 22 Aug 2009 02:47 AM |
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Thanks for the info ecobuilder.
It's been some time since I posed this question. The urethane SIPs manufacturer of my choice answered my question of whether to build with urethane foam or EPS. The urethane SIPs simply can't span the length I need for my roof system so I'm not going with them. Even though they might have the best wall system in the business, it's the roof where the insulation counts. So, I'm going with EPS for the roof AND the walls. In my neck of the woods... that means Korwall.
I'll start a different thread to monitor the progress of that venture.
And no, Chris Kavala. I'm not going to consider steel SIPs. 
Ras
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Sip Supply Inc
New Member
Posts:44
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| 22 Aug 2009 06:08 AM |
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Posted By RasThavas on 08/22/2009 2:47 AM
And no, Chris Kavala. I'm not going to consider steel SIPs.
Ras
Steel Sips!, when did they start making steel SIPS?  |
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| [email protected] |
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ErgoDesk
Basic Member
Posts:149
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| 22 Aug 2009 03:04 PM |
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Excellent choice Ras! EPS retains Insulating Values much better that the other ... |
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| Build Smarter with Structural Insulated Air<br>http://StyroHomeNews.blogspot.com |
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RasThavas
New Member
Posts:5
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| 23 Aug 2009 05:59 PM |
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Posted By Sip Supply Inc on 08/22/2009 6:08 AM
Posted By RasThavas on 08/22/2009 2:47 AM
And no, Chris Kavala. I'm not going to consider steel SIPs.
Ras
Steel Sips!, when did they start making steel SIPS? OK, the metal clad ones! SIPS of Steel! That sounds like a good slogan. |
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