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Peter McManus
Registered Users
Posts:10
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| 06/03/2008 6:20 AM |
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Discussed the foam board option you proposed with my builder. He was not sure why you recommended no plastic vapour barrier. Also, he had originally planned on putting the foamboard on the interior wall.
Any thoughts? |
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Intrigue
Registered Users
Posts:11
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| 06/03/2008 7:14 AM |
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The foamboard goes on the exterior of the wall because it will insulate the thermal bridge caused by the 2xs. As your builder should know, the studs are the weakest link in the insulation. That's why SIPs are good.....there are no studs. By adding the foamboard, the studs are insulated.
The foamboard serves another purpose. Most basement walls in Ontario now have foamboard applied to the exterior. The builder can continue that same foambord right up the house. This way you've insulated the thermal bridge where the basement wall meets the wooden wall. You also don't need housewrap on the exterior wall. The foamboard is air and water tight. Just need to make sure the proper tape is applied to the seams and high quality caulking is used.
The spray foam is applied to the interior.....it acts as a air and vapour sealant. Since the spray is your vapour barrier, you don't add the plastic barrier. That would make it 2 vapour barriers and thats a big no-no so any vapour that enters the batt insulation from the interior will essentially be trapped.
For windows, you might want to checkout these guys (they have won awards for their energy efficient windows):
http://vinylwindowdesigns.com/sites/S1/index.php?p=1
For the basement, assuming you have a concrete or block foundation wall, the builder will apply the black sealant, then the foamboard. I would also reccomend he wraps the wall with the Delta membrane (not expensive even available at HomeDepot):
http://www.deltams.com/
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Peter McManus
Registered Users
Posts:10
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| 06/03/2008 11:46 AM |
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| Thank you once again. Now I have another twist, My mechanical guy has advised me that this solution might be outside the 1/3- 2/3 code rule. Not sure what he means? |
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Paulcf
Registered Users
Posts:17
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| 06/17/2008 8:44 PM |
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I was involved with a house build in Colorado with sprayed in foam (polyurethane) for the ceiling. It appeared to be the ideal thing for the cathedral ceiling. Then, in the winter, drips of water started appearing, staining the wood that was installed on the rafters against the foam. Dripping down like rain, not ideal for electronics! The ceiling wood was peeled off and we found water (of course) caused by condensation of warm, humid air. What happened is that the wood rafters continued to shrink and twist imperceptibly but in small enough amounts that all it needed was cracks for the warm humid air to meet the cold outside air at the roof. Condensation formed of course and if left unchecked, rot and black mould would take their course.
To correct this, we had to scrape and remove all the foam. The problem was that the foam is sprayed on, whilst our SIPs it is injected at over 2,000 PSI and it chemically bonds with the OSB or whatever skin being used. Back to the house, we let the ceiling dry further, using fibreglass for 1 season and then reapplied the spray foam. Due to excessive delivery costs, SIPs were not possible here (over 10,000 ft above sea level !).
I can't imagine having anything but a SIP for my foundation walls. Think about it. People with concrete basements have about 2-5 feet of exposed concrete, an ideal cold sink to bring cold into their basement and then they wonder why it's still cold even with the foam sheets applied...but of course you know that those sheets are underground, serving little purpose.
Lessons learned there! I did see mention of the fact that you're still having to frame the house, using lots of lumber obviously for spray foam...whereas our SIPs have NO dimensional lumber (unless load points or tall wall situations of course), so no thermal bridging.
Our 6 1/2" OSB/OSB SIPs is R-44 as we use polyurethane injected foam. It's an expensive SIP but when you compare to all the costs and labour, it comes out to about the same as a stick build.
One key criteria about SIPs that is rarely mentioned: Think about this....we are putting the quality into your walls in our climate controlled factory, under ideal conditions, for workers to work standing up (not bent over on a slippery floor with howling ice winds and pelting rain). The quality goes in to the panel and then it is all custom fabricated and shipped. You assemble a Lego house! There's a reason why we don't build cars or anything else major or complicated in our garages (in volume) and for consistency. So why do we continue to build houses outside, under all types of climatic conditions, the same way they were built about 100 years ago? If cars have evolved with their fabrication, isn't it time the housing construction business realized and did the same?
When people harness the power of the Internet, read up about the fibreglass being pulled over their eyes, and start to demand houses be energy efficient, quality structural strength, and faster to assemble, then SIPs will be marginalized but like any good thing, I know SIPs will prevail, the ultimate motivator is causing it to happen, energy costs are skyrocketing and the pocketbook will create the need.
I look forward to working with builders who see the future (very close horizon) and want to keenly differentiate themselves and own the future of true energy efficiency and quality in a home build.
Sorry about the ramble, good luck Peter with your home build and post some pictures on what you do. In the meantime, be sure to check out this neat video I found on youtube...this will clearly illustrate the differences in the 2 types of foam out there: http://www.youtube.com/watch?v=1ooQEBPQBnw
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cmkavala
Registered Users
Posts:808
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| 06/18/2008 8:11 AM |
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Paulcf;
Exactly what happened with the OSB sips in Alaska some years back,
you make a great case for steel sips
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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ReadyToRetire
Registered Users
Posts:195
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| 06/18/2008 4:08 PM |
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Paulcf,
I'm having a hard time seeing how the "test" is relevant. If I'm in a house and a fire has grown to the point where the wall interior is exposed to the temperature of propane flame, my guess is that the least of my concerns will be how long the wall lasts.
Do you have any demonstrations of fires within the building?
Larry
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PanelCrafters
Registered Users
Posts:1323
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| 06/18/2008 7:26 PM |
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Posted By Paulcf on 06/17/2008 8:44 PM
Due to excessive delivery costs, SIPs were not possible here (over 10,000 ft above sea level !).
We have done it. And, the 'delivery costs' argument is bogus. A mile is a mile.
I also agree that the 'fire scare' is just that. If the fire gets to the OSB(or steel for those fans), past the drywall, the house is gone. It doesn't matter, at that point, what type of foam is within the panels. Anyone still in the structure would have already died, and the place would have to be demo'd and rebuilt. |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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Paulcf
Registered Users
Posts:17
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| 06/18/2008 10:43 PM |
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JC/PanelCrafters: delivery costs WERE the issue. Sorry but I have the facts. It was 1 house and it's long since been built as I described.
Larry: You may have overlooked the point in my discussion and the subsequent facts. We HAVE fires on 1st Nation lands (extreme north of Canada) and when a house catches fire, invariable the WHOLE side of the street burns, there is NO fire department and in winter, lines, if they existed, are frozen solid. Sadly these reserves are lucky to even have running water. In one fire, the SIPs kept the fire inside the structure it did NOT spread and the FOAM didn't burn or contribute to fire. Given this situation, everyone got out of course, and then the intense heat incinerated everything inside the house to ash, as the SIPs radiated the heat back into the structure. But NO other homes were lost. Had the foam burned, it would have radiated fire to the next house and the domino effect would happen.
Chris Kavala: Chris, did you investigate the Juneau, Alaska SIPs situation? It has NOTHING to do with SIPs. I investigated it. It had everything to do with poor workmanship. No splines were used, gaps were up to 3 INCHES between butt ends of panels, and the gaps were merely spray foamed in. Thus no matter what or built with no matter what, water seepage was guaranteed which led to substrate failure and rot.
Thanks everyone, let's work together to advance SIPs to builders who need our guidance to build a better home. |
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cmkavala
Registered Users
Posts:808
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| 06/19/2008 7:53 AM |
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Posted By Paulcf on 06/18/2008 10:43 PM
JC/PanelCrafters: delivery costs WERE the issue. Sorry but I have the facts. It was 1 house and it's long since been built as I described.
Chris Kavala: Chris, did you investigate the Juneau, Alaska SIPs situation? It has NOTHING to do with SIPs. I investigated it. It had everything to do with poor workmanship. No splines were used, gaps were up to 3 INCHES between butt ends of panels, and the gaps were merely spray foamed in. Thus no matter what or built with no matter what, water seepage was guaranteed which led to substrate failure and rot.
JC;
yes, the spline mastic was not installed and the wood splines shrunk, yes improper workmanship.
That black eye affects all of the SIP industry and I often need to explain away a problem that never involved a steel SIP.
My previous point was that there are no splines to shrink in a steel SIP assembly, and even if there was a breach in the joint, there is NEVER anything to rot or cause mold due to condensation
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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ReadyToRetire
Registered Users
Posts:195
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| 06/19/2008 8:10 AM |
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Paulcf,
You're right, I had overlooked that.
So, as I understand your issue, your concern is community protection -- by containing a fire within a single structure -- rather than occupant protection. (Similar to the fire after the San Francisco earth-quake.) If there were no functioning fire-fighting infrastructure, then, yes, I can see the possibility for a community advantage. It would be interesting to have a controlled burn with each of the systems to see how they actually performed for external-fire spread.
Very respectfully,
Larry
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PanelCrafters
Registered Users
Posts:1323
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| 06/19/2008 9:08 AM |
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Posted By cmkavala on 06/19/2008 7:53 AM
Posted By Paulcf on 06/18/2008 10:43 PM
JC/PanelCrafters: delivery costs WERE the issue. Sorry but I have the facts. It was 1 house and it's long since been built as I described.
Chris Kavala: Chris, did you investigate the Juneau, Alaska SIPs situation? It has NOTHING to do with SIPs. I investigated it. It had everything to do with poor workmanship. No splines were used, gaps were up to 3 INCHES between butt ends of panels, and the gaps were merely spray foamed in. Thus no matter what or built with no matter what, water seepage was guaranteed which led to substrate failure and rot.
JC; yes, the spline mastic was not installed and the wood splines shrunk, yes improper workmanship. That black eye affects all of the SIP industry and I often need to explain away a problem that never involved a steel SIP. My previous point was that there are no splines to shrink in a steel SIP assembly, and even if there was a breach in the joint, there is NEVER anything to rot or cause mold due to condensation
You are addressing the wrong poster! |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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cmkavala
Registered Users
Posts:808
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| 06/19/2008 9:10 AM |
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| Sorry JC I'm just a feeble minded steel sip builder |
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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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| 06/19/2008 10:30 AM |
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| Fire test are available for steel sips. I have a copy if anyone is interested it is from Western Fire Center, from June 3, 2004. After an hour at 1000 degrees the steel sip panel had the skin cut away and the foam on the inside looked as though it just came from the factory. So Yes steel sips that are fire proof walls, could still be used or left standing if it under goes a fire. I am for a product that is air tight so much that a fire doesn't spread to other rooms even if it breaks out say in a bed room, and stays there and burns out, this protects the rest of the occupants in the home and the home it self. My homeowners insurance was reduced because of this listing the structure as structural steel non-combustable. |
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Intrigue
Registered Users
Posts:11
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| 06/19/2008 6:58 PM |
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Fire resistance may be a point but, at, best, a very small selling point. The odds of a full-scale fire are slim and on the slim chance that there is a fire, that's why God invented insurance. Fire is a devastating thing, but there isn't much point in having the outside walls intact when all the internals (including personal possessions) are burned to a crisp and the roof is toast. Whatever the fire doesn't get, the smoke damage will surely destroy.
For those few specific cases where fire or the spread of flames may be a valid concern perhaps ICF would be a better alternative. Or, install a whole house sprinkler system. Steel SIOPs may be nice, but there are enough combustibles in any house that having outside walls that don't burn is just making a giant fire-pit.
Kinda begs the question, does a homeowner spend the extra money on steel SIPs so that he has the outside walls intact or does he spend the extra money on a sprinkler system and have his possessions intact.
Seems like a no-brainer to me. |
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GeorgiaTom
Registered Users
Posts:130
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| 06/19/2008 8:38 PM |
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Not much point in the contents being intact either if going to get rained on for a couple hours
cases of fire breaking out in SIP construction usually get starved for oxygen and burn themselves out
I remember the heavens and the earth, what part was insurance? |
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Intrigue
Registered Users
Posts:11
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| 06/19/2008 10:29 PM |
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Are you kidding me!
I'd much rathur have my contents sprayed by water than burned to an ash. Sure, I'd lose some, but burning I'd lose it all, except my steel SIP outside walls. Yippee!
Do you have even one real life example of a house fire with SIPs where the fire went out because of oxygen deprivation. That just won't happen. If it where that air tight the windows would implode way before the fire went out.
Someone needs to really take a look at what a fire really does. Besides the tremendous heat, and the volumes of smoke, fire gets inside the walls, travels upwards, consuming the ceiling and roof. Fire goes upwards and when the upward travel is consumed it spreads outwards. The outside walls aren't usually where a fire starts. Doesn't matter if they are SIP or stick, the outside walls are the last to burn. By that time the inside is virtually a writeoff.
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GeorgiaTom
Registered Users
Posts:130
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| 06/20/2008 6:52 AM |
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No kidding here, I could not find anything about insurance but, there was a big flood.
yes there is an incident about fire burning its self out check with SIPA
but if your ERV was running you would be feeding the fire |
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freakboy
Registered Users
Posts:32
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| 06/20/2008 1:34 PM |
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I would like to address the vapor barrier issue again. It would be extremely important to be sure that the wall framing is dry prior to installing rigid foam on the outside of the structure and of couse before spray foam inside. Most contractors would probably not care if the wood were wet prior to installing the rigid foam causing moisture to be trapped. I know some foam panels have a perm rating which does not allow water to be absorbed and some do not, be sure to clarify the difference.
Why would the fiberglass be necessary for the rigid foam panels/stick frame/spray foam inside system. I would not take the chance of the fiberglass acting as a sponge trapping moisture.
I am currently helping a friend with an ICF home and it is easy but labor intensive. Looking for other alternitives and feel sipp or the stick/foambord/spayfoam is the way to go. I am still not sure about the whole thermal mass thing.
I have remodeled some of my own work for various reasons thru the years and found that the fiberglass which I installed with great care had developed gaps around the joints. The more research I do the more I find out about the fiberglass myth. Skip the fiberglass and add 1" more spray foam.
Found a great site today called Soythane. 1.5# closed cell foam for DIY installers about .75 cents B/f material costs if buying in quantity. Looks like someone may have come up with a easy to use spray gun here. The company is somewhere in FLA and appears fairly new.
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Dont run thru the forest with your face on fire
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