HI: I'm New to this forum. Lots of great info in hear. I'm building a ~4000sqft home in south central Indiana. I was initially considering doig it with stick built methods but now I'm considering that it may be better with SIPs. There are lots of cathedral ceilings and I think the design would lend itself to SIPs roof panels well. The concern I have is getting the electrical and HVAC systems work done with SIPS. I'm the GC and I'm wondering if I would be severly limiting the pool of qualified subs. Should I be worried? Thanks

Hey indianaEPH,
I used Thermocore in or near Indianapalous for my panels, and they recommended an installation crew too. I used them and they were great and fast 6 days. I'm sure either Thermocore or the install crew will know of knowledgable subs for HVAC and elect., remember plumbing must be in the floor, not inside a SIP. Recently I watched about an hour's worth of You Tube and there are some good vids on erecting the shell, and SIP school would help a lot if you have never been around this type of construction.
Good luck
Dan

Thanks for the info. I'm going to contact them this week. I also have watched amny you tube videos.

Be careful of SIP's for the roof. I have a timber frame home, vaulted ceilings with 1X6 T&G pine layer down for the vaulted ceiling inside, then 6 mil poly, then SIP's (6.5" polystyrene) panels and then the roofing. Now I admit I live in Alaska but I would have never dreamed that my panels would fail but they have. Snow load of approximately 3 to 4 feet has caused the panels to get dips and sags due to load crushing the foam inside of the SIP's. there is no deflection of the panels on the inside of the house, just the roofing shingles. We removed roofing at the peak to check for moisture and found none per engineering firm looking at problem. They have determined it is snow load that has crushed the panels and advised over building the roof with framing, sheeting and a new metal roof so snow slides off. By the way, panels where made in New Mexico by KC Panels and they are the lowest density foam available and they went out of business 2weeks after we notified them of the problem.

Snow load of approximately 3 to 4 feet has caused the panels to get dips and sags due to load crushing the foam inside of the SIP's

I'm not following that at all. Even in Fairbanks you gotta build to 50 pounds per square foot on the roof loading. 50 psf is less than 1/2 lb psi which itself is a small fraction of most foam compressibility. The foam used in them can't be that soft, can it? Is it possible your foam shrank over time? A poor chemical mix by the maker?

That has been mentioned and a possibility i thinking. From what I have learned so far from the engineers i have talked to, I have white urathaine foam which is the lowest density and in New Mexico the engineers here say it would be fine there. Up here in Alaska I should have had purple or blue foam which is much higher density and can handle compression much better. I saved a samples of the SIPs and we looked at them closely, you can physically compress the panels sample with a squish of the hand. Yes we build to 50 PSI load here to but no one here though obout this problem. I assumed it would be just fine. After ten years in service I now have to to do something to lighten the loading on the roof. The roof started showing dips about 3 summers ago.

I believe the problem was that the SIP company who manufactured the SIPs was not reputable. Something went horribly wrong during the manufacturing process. That is why I am opposed to these DIY SIP companies. I really don't believe SIPs should be something someone should be creating in their backyard or garage.

Stick with a reputable SIP manufacturers and you won't have problems. When you try these fly-by-night companies you are taking a huge risk.

Posted By kenaiman on 28 Mar 2013 12:11 AM
That has been mentioned and a possibility i thinking. From what I have learned so far from the engineers i have talked to, I have white urathaine foam which is the lowest density and in New Mexico the engineers here say it would be fine there. Up here in Alaska I should have had purple or blue foam which is much higher density and can handle compression much better. I saved a samples of the SIPs and we looked at them closely, you can physically compress the panels sample with a squish of the hand. Yes we build to 50 PSI load here to but no one here though obout this problem. I assumed it would be just fine. After ten years in service I now have to to do something to lighten the loading on the roof. The roof started showing dips about 3 summers ago.

many SIP manufacturers use EPS re-grind foam and 1 pound nominal, that can actually be as little as .90 per cu ft.

We use virgin 1# minimum (1.0 - 1.15)and much better for structural purposes and thermal insulation
in my opinion re-grind should only be used for foam packaging, it has poor structural perforamance

I think you mean 50 PSF design, 50 PSI = 7200 PSF

Yes I meant 50 SPF, sorry for that.

you can physically compress the panels sample with a squish of the hand

With your hand? What bad luck.

Ok I'm having a bad day, fat fingers really meant 50 PSF.......
Ok, I'm now confused??? Re-grind foam ???? These SIP's are polyurethane sprayed panels that are put into a form with OSB on each side and then spray filled with polyurethane foam. I can't imagine re-grind going through a sprayer or something like that but I have been surprised before. Now that I think about it fiber glass chopper guns work like that. Have I been screwed or what.......
If I would have used metal roofing from the bargaining on this 12/12 pitch roof I'm thinking it would have been a non event for us.

Posted By kenaiman on 28 Mar 2013 06:20 PM
Ok I'm having a bad day, fat fingers really meant 50 PSF.......
Ok, I'm now confused??? Re-grind foam ???? These SIP's are polyurethane sprayed panels that are put into a form with OSB on each side and then spray filled with polyurethane foam. I can't imagine re-grind going through a sprayer or something like that but I have been surprised before. Now that I think about it fiber glass chopper guns work like that. Have I been screwed or what.......
If I would have used metal roofing from the bargaining on this 12/12 pitch roof I'm thinking it would have been a non event for us.

Sorry re-grind reference was to EPS, but then I have not seen white PU either, it is always yellow

Yes your right, yellow would be more correct. White for a short time then turns yellow quickly.

I am leaning towards the possibility that the panels actually delaminated from the foam. The OSB and foam bond failed and the panels therefore fell apart and sagged. The sags you see is the failed bond between the OSB and foam. The foam crumbling is probably the failure of the foam and causing it to crumble away. Like Chris said, they could have used a poor quality (recycled foam) and it was part of the delamination issue.

This is a pic from last year. You can see the problem big time. If I could figure out how to post it.....

Maybe I should just pull off the panels and start over

Posted By kenaiman on 29 Mar 2013 12:03 AM
This is a pic from last year. You can see the problem big time. If I could figure out how to post it.....

Just go down to "Attachments" and click the arrow. Find the file and upload it. It has to be under 100Kb.

I don't like OSB SIPs for roofs. I am really a fan of steel SIPs because you don't have the issue of rot and they can span larger distances and carry less dead load than a wood SIP.

Did you ever read this Building Science Article:

SIP ROT

The urethane foam was poured at a very low density. This can be verified by weighing a foam core sample. It should weigh about 2.3 lbs per cubic foot. At the wrong density delam., crushing and total failure can happen. This is not a problem for Sips that come from a reputable dealer and properly documented from the manufacturer.

Another reason why I avoid wood roof trusses or wood SIPs. My buddy of mine found this in his home the other day:



This is what happens in Arizona when you have wood roof trusses in your attic. There are the subterranean termites which tunnel through the wood walls and eventually make their way into the wood truss attic. The other are the Folsom Termites which fly into your attic via the numerous opens gable and soffit vents and set up shop. The latter is harder to spot because they fly into the attic and start their damage and by the time you notice it, you are looking at thousands if not tens of thousands of dollars in repairs.

With a Steel SIP roof, you don't have the wood truss problem, the problem of venting the attic, the wood/OSB problem, and the subsequent termite problem. The Steel SIP roof EPS is treated with borates.

He is looking at a hefty pest control bill ($1,500 - $5,000) and that is not counting the damage done to the wood roof trusses and his interior wood walls.

I just think wood truss attics in Arizona is nothing but headaches and long term maintenance and pest problems. It's a multimillion dollar industry out in Arizona treating and dealing with termites in attics and wood walls. There are better alternatives out there with modern building techniques (steel SIPs, ICF) but they continue doing the wood truss and frame method. Everyone I know with a wood truss attic eventually either gets infested with termites, mice, pack/roof rats, bats, scorpions, and even pigeons (Phx area). The same goes for wood wall assemblies out here. I've seen 5 year old walls torn apart and filled with termites and scorpions. Arizona's climate and biology is not kind to wood, yet that is 98% of what they use to build homes.

trying pic's again for you all. I did what you said and i don't see pics on preview????? It says i have 2 pic's attached