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Jelly
Registered Users
Posts:269
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| 11/12/2007 4:21 PM |
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Hey now, no need to argue - whether SIPS or ICF, we're here to learn and discuss alternatives to conventional stick framing, which obviously has severe issues, especially where I plan on building (southern Louisiana). I'm just a DIY dreamer who hopes to build within a year - so I don't have any allegiances, but I've got some very basic construction skills. What's important for me is bottom-line cost and the ability for me and my inexperienced crew (my in-laws and my retired pop) to do most of the work.
I started out researching dry-stacked reinforced fully-grouted CMU with EPS foam placed on the exterior. That brought me to ICF (less heavy lifting, furring strips already embedded in the foam, wiring runs made with a hot knife). The price for ICF is higher, but when you add the cost of exterior foam and wiring conduit for the CMU, the difference gets smaller and the quicker ICF installation starts to look good. Still I couldn't seem to get past insulating your thermal mass from the inside with the ICF forms.
Panelcrafters - I'm so glad you posted the link to that Oak Ridge study. I've been trying to pin this thermal mass issue down via extensive googling and participation on three different forums for the past several weeks. My tentative conclusion was that the best scenario is external insulation with thermal mass on the interior (despite lots of opinions to the contrary). Now I finally have documentation that directly supports my conclusion!
Still I wonder if the difference in thermal mass energy performance from externally insulated solid grouted CMU and an ICF wall is really all that great.
Ok SIPS has no thermal mass, but it's very well insulated so it performs well in hot climates with conditioned interiors. So, how DIY friendly is SIPS? I would only consider steel SIPS. Seems like you've got to order custom-prepared panels? Or is it easy enough to put smaller units together, cut window openings and install lintels/headers? How about for 12 or 14 foot high walls?
How do you apply stucco to steel SIPS - furring strips then lath? And can you put gypsum board directly onto the interior surface?
Is the panel-base/sill-plate to foundation connection a common insect infiltration site?
I don't see why you couldn't put a SIPS roof on an ICF structure. Seems ideal actually. A masonry gable end could easily support the ridge beam. Then the SIPS panels could be attached to the walls with bolts.
I hear a lot about flat SIPS roofs. Why do SIPs lend themselves well to flat roofs, and are they really flat or is there a slight slope just like all "flat" roofs?
Lots of questions, I know, but I need lots of answers! :)
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cmkavala
Registered Users
Posts:807
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| 11/12/2007 6:32 PM |
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Jelly;
We just offered tech support for a 2100 sq. ft. duplex built wilth steel sips and a bunch of volunteers for the New Tribe Mission , Sanford, Forida
Job started at 9: 30 AM Monday and was dried -in on Wednesday 10 AM
Steel SIP notes:
can balloon frame up to 3 - stories high
panels available up to 53 ft. in length
window openings less than 6 ft. are wrapped with 18 ga. channel
Stucco applied to paperbacked lath screwed directly to steel skin with wafer head screws
interior is furred with 1-1/2" steel hi-hat, then drywalled, electrician uses a 4 square box with 1/2" plaster ring - no need to cut skin
you can attach SIPs to ICF wall with 2x10 PT plate and LD sip screws
If you would like a set of connection details please e-mail me directly and I'll send you a set in PDF format |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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PanelCrafters
Registered Users
Posts:1323
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| 11/12/2007 6:38 PM |
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Posted By Jelly on 11/12/2007 4:21 PM
Panelcrafters - I'm so glad you posted the link to that Oak Ridge study. I've been trying to pin this thermal mass issue down via extensive googling and participation on three different forums for the past several weeks. My tentative conclusion was that the best scenario is external insulation with thermal mass on the interior (despite lots of opinions to the contrary). Now I finally have documentation that directly supports my conclusion!
I thought that people would find the info interesting. Did you view the figures(especially #8)? That pretty much tells the story. In cold climates(Boulder & Minneapolis) you are only looking at a max 8% energy savings. And, some of that is no doubt due the increase in R-Value and the decrease in Air Infiltration. Not exactly the kind of ROI you'd be looking for with the additional cost over stick framed. R-50? Only in someone's dreams. |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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Jelly
Registered Users
Posts:269
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| 11/12/2007 8:29 PM |
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Posted By PanelCrafters on 11/12/2007 6:38 PM
In cold climates(Boulder & Minneapolis) you are only looking at a max 8% energy savings. And, some of that is no doubt due the increase in R-Value and the decrease in Air Infiltration. Not exactly the kind of ROI you'd be looking for with the additional cost over stick framed. R-50? Only in someone's dreams.
Oh, yes I did look at the figures, and I have to admit those energy savings sound way too low. I'm not sure how they arrived at that, but real-world comparisons put the energy savings way higher than that.
Ask anyone who lives in a massive wall structure after having lived in a stick-built house. You'll hear people say it cut their electricity bills literally in half. I wish they had included SIPS for comparison, but if they had I would imagine those numbers would be lower than you would think they should be too (in that study I mean - not in general).
I was actually responding to the part that said including internal insulation on a massive wall structure doesn't perform as well as having only external insulation. The benefits of massive walls are not really in dispute (at least not to me, that is), but the question of where does the insulation go is often debated.
So that leads me to another question about SIPS, and that is how does it perform in a hot and humid environment that doesn't cool down at night? The foam insulation layer will do a great job of slowing the transfer of heat, but only for so long. I mean it can't resist it forever, right?
So if there is no thermal mass, then where does the heat go? The great thing about steel and light framing is that they cool off quickly. That's great for a climate where it cools down at night. But what about a place that makes you sweat as much or more at night as you do in the day time? As long as you're conditioning the air I'm sure you're fine. And I don't mean to suggest that you couldn't stay comfortable. But what about total energy performance to keep it cool?
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Quantum
Registered Users
Posts:262
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| 11/13/2007 8:53 AM |
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Jelly, CMU has virtually no insulative value, and far less thermal mass than concrete. It's sort of the worst of all worlds.
And SIP is used often for roof over ICF. You can special-order for sloped ends to compliment the roof slope. I prefer though, the cheaper method of steel truss with expanding foam sprayed in the rafters.
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PanelCrafters
Registered Users
Posts:1323
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| 11/13/2007 9:39 AM |
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Posted By Jelly on 11/12/2007 8:29 PM
So that leads me to another question about SIPS, and that is how does it perform in a hot and humid environment that doesn't cool down at night? The foam insulation layer will do a great job of slowing the transfer of heat, but only for so long. I mean it can't resist it forever, right?
So if there is no thermal mass, then where does the heat go? The great thing about steel and light framing is that they cool off quickly. That's great for a climate where it cools down at night. But what about a place that makes you sweat as much or more at night as you do in the day time? As long as you're conditioning the air I'm sure you're fine. And I don't mean to suggest that you couldn't stay comfortable. But what about total energy performance to keep it cool?
It all boils down to R-Value. The higher the value the slower that heat can enter or escape a structure.
So, let's say we are in a hot climate where it gets to 100° during the day, and you want the house at 70°. That gives us a Delta T of 30°.
For a 1,000 sqft of R-20 surface you've got: 1/20 x 30° x 1,000 for a Heat Gain of: 1,500 BTU/hr.
For a 1,000 sqft of R-100 surface you've got: 1/100 x 30° x 1,000 for a Heat Gain of: 300 BTU/hr.
Big difference isn't it? |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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Jelly
Registered Users
Posts:269
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| 11/13/2007 10:56 AM |
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Posted By Quantum on 11/13/2007 8:53 AM
Jelly, CMU has virtually no insulative value, [i]and[/i] far less thermal mass than concrete. It's sort of the worst of all worlds.
And SIP is used often for roof over ICF. You can special-order for sloped ends to compliment the roof slope. I prefer though, the cheaper method of steel truss with expanding foam sprayed in the rafters.
Hi Quantum, I think we're just talking cross-purposes. Yes if you're thinking of just a hollow buttered CMU wall with no insulation then of course it has no insulative value. If you poured an ICF wall and stripped away the EPS forms then it would have virtually no insulative value either.
You said CMU has far less thermal mass than concrete, but CMU *is* concrete (CMU = Concrete Masonry Unit). Ok, again, if you're thinking of a hollow CMU wall then it has less thermal mass than a solid wall.
But like I already mentioned, if the CMU is reinforced and fully-grouted (in other words all the voids are filled with concrete) then you end up with an 8 inch thick mass of steel reinforced solid concrete - just as much thermal value as an ICF wall.
Then if you clad the exterior with EPS you've got your insulative value, and the thermal mass is still to the inside of the building where it can do its work. The results of the mentioned Oak Ridge study would imply that this would be more energy efficient than a common ICF wall.
I should clarify that in this equation I'm considering CMU with open ends and short webs (like Azar or Haener) - when stacked in a running bond all the cells are interconnected, in other words you can grout with a boom like with ICF forms and the grout will spread out in all directions within the wall. This wouldn't be the same story with standard 2-cell closed-end CMU with the webs that go all the way to the top of the block.
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cmkavala
Registered Users
Posts:807
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| 11/13/2007 5:59 PM |
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Quantum;
"the cheaper method of steel truss with expanding foam sprayed in the rafters." Costs about 30% more in our area. The steel truss being the expensive part |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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Quantum
Registered Users
Posts:262
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| 11/13/2007 8:03 PM |
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Well Jelly, if we're talking at cross-purposes I'll just leave it at that.
And good to know Chris. Where is your area in the South? Steel has gone up considerably, due to demand in Red China. |
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Jelly
Registered Users
Posts:269
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| 11/14/2007 2:56 AM |
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cmkavala - I assume that steel SIPS are more expensive than OSB SIPS for this reason, too (price of steel)? Is that true where you are?
I can't seem to find any realistic figures though about price. Do you have a ballpark figure that suggests what steel SIPS construction is going for in your region?
Wouldn't it be great if there was some place where you could look at real figures that compare cost of various construction methods and get real objective answers that aren't tweaked by someone's allegiance to one method or industry or another? |
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Jelly
Registered Users
Posts:269
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| 11/14/2007 3:34 AM |
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Posted By Quantum on 11/13/2007 8:03 PM
Well Jelly, if we're talking at cross-purposes I'll just leave it at that. Oh well, Quantum, it's a shame if you want to just leave it at that. You're obviously knowledgeable and I've gotten good information from your previous posts in the various forums. I'm just trying to learn, so clarifying what I'm talking about helps me to get the right input from people in the know.
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cmkavala
Registered Users
Posts:807
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| 11/14/2007 6:08 AM |
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Quantum;
We are loacted in the Tampa area and North Georgia areas
Jelly;
Steel in the steel SIPs is one of the smaller components @ 26. ga. thick, so the steel pricing does not necessarily increase like steel trusses where steel is the only component in them.
As far as OSB vs. Steel skins, we have found that the steel SIPs are less expensive for the following reasons:
- they require no splines
- they have a built in vapor barrier
- do not need to rout for window and door bucks
- no crane required to set
- home owners insurance is 50% less than OSB/wood frame
- the underside of the roof panel creates a pre-finished soffit
- builders risk insurance is less due to all steel construction
- Steel SIPs have greater span capabilities and are available in longer length eliminating splices
- balloon framing 2 storys eliminates 2 layers of top plates/ labor |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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Donaldson
Registered Users
Posts:90
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| 11/14/2007 8:21 AM |
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Jelly,
My house has a total of 3840 sq. ft under roof two stories, as an owner builder having a sip crew put up the shell of my house and frame it in on the inside to trade ready, and including the cost of 26 high end double pained windows my steel sip home was trade ready for about $17 sq ft. At that time conventional construction was going for about $80 sq ft for trade ready with a finished priced of $125 sq. ft. My finished price with me running the trades and after a drywall crew put up the dry wall I finished out the rest, I have a total of $43 sq. ft. in the house. I didn't do cheep either I have high end appliances, custom cabinets, and hard wood floors through out. These are 2005 figures. I did design the house for ease of construction ie one big rectangle box. Having watched the house go through three hurricanes I would say it is a great deal.
Also if I lived in a "flood zone" then I think I would spend a few $ on a good caulk and caulk the seems of the panels and then paint with a good elastomeric paint and be done with worrying as i don't think standing water would ever get through the seems to the foam and i know it is not going to go through 26 ga. steel! |
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slenzen
Registered Users
Posts:163
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| 11/14/2007 8:59 AM |
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| Donaldson, can you post pics of your house? Sounds like something I am interested in here in MN. |
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slenzen
Registered Users
Posts:163
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| 11/14/2007 9:03 AM |
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Are the steel sip systems being discussed the same as LINK? I have seen them post blogs at livemodern.com.
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cmkavala
Registered Users
Posts:807
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| 11/14/2007 4:24 PM |
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Posted By slenzen on 11/14/2007 9:03 AM Are the steel sip systems being discussed the same as LINK? I have seen them post blogs at livemodern.com.
No those are not a true SIP they are like on
LINK
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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mcinfantry
Registered Users
Posts:9
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| 11/16/2007 12:52 AM |
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jelly, i have built 1800 s.f. shop (22 foot ceilings) in the baton rouge area and am currently building 5400 s.f. in biloxi ms... im using actech panels.
in my shop in the winter a portable kerosene heater that is rated for 1000 s.f will literally run you out of the shop. i have two roll-up 12x14 doors that are r-17. i have yet to see a larger than 5 degree swing in temperature from sundown~sunrise. regardless of temperature. |
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Jelly
Registered Users
Posts:269
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| 11/16/2007 4:28 AM |
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Posted By mcinfantry on 11/16/2007 12:52 AM
jelly, i have built 1800 s.f. shop (22 foot ceilings) in the baton rouge area and am currently building 5400 s.f. in biloxi ms... im using actech panels.
in my shop in the winter a portable kerosene heater that is rated for 1000 s.f will literally run you out of the shop. i have two roll-up 12x14 doors that are r-17. i have yet to see a larger than 5 degree swing in temperature from sundown~sunrise. regardless of temperature. Hi mcinfantry, I'd like to talk to you more about SIPs in Baton Rouge. I'm sending you a PM.
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mcinfantry
Registered Users
Posts:9
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| 11/16/2007 8:53 AM |
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| got it. anyone else need any info, pm, email or you can call me. |
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