We are very sad that we chose Structural Insulated Panels (SIPs) for our home. We thought we were being environmentally greener and smarter than our “stick-built” neighbors. We wanted a house that was energy efficient, low maintenance and that would last more than a lifetime. Even though we initially paid thousands more to build our SIP home, we truly believed that it was stronger and would outlast other homes. Our SIP home is only 22 years old and unfortunately we are beginning to see our SIPs deteriorate (this began about 7 yrs ago). We are seeing sagging on both the exterior roof and interior ceiling. We have a ranch style home and the entire south roof is sagging by length and width. So not only are the SIPs showing sag but also the supporting 2x6”s running from the roof peak to the bottom roof edge (measured up to 2” gap). The panels are 4’ x (up to) 14’ with 3/8” OSB interior and exterior skin. They have 5 5/8” EPS (foam) core. There are supporting 2x6’s on each end of the 4’ panels but none between the 4’ span. These SIPs are manufactured by Insulspan (through Foam Products Corporation out of Maryland Heights, MO). Insulspan has moved and is currently located in Blissfield, Michigan. We have contacted both Insulspan and Foam Products and we have been offered no assistance or even suggestions to remedy this major issue. Each stated they will not accept responsibility. Is the SIP industry not prepared to stand by their products? We are very concerned about the structural integrity of our home now (recently hearing lots of popping) and are unsure where to even begin the process of fixing this problem. Our original contractor has contacted another area SIP manufacturer for repair ideas. This company has suggested constructing another layer on top of the exterior panels with 2x8” rafters. Then jaking up the interior ceiling and using long screws and large washers to screw into the new 2x8 rafters. The rafters would then be covered with OSB and a metal roof. We spoke to another Insulspan/ Foam Products customer who had exact same issue (his house built in 1992)and he added interior support by constructing additional beams to reduce the span. To repair or replace SIPs seems an almost impossible project. I have reviewed many posts on this site and there seem to be so much knowledge about SIPs. Our hope is that someone can offer advice to this major SIP problem. Which method would be the best to fix our situation? What are some other options besides removing and replacing the entire SIP structural roof? So very grateful for any response. Morrie and Barb Fraser 618-541-0194 Will attempt to upload a few exterior & interior pics.

Trying to diagnose an issue on the forum is probably not the best method. If you haven't already done it ,get a structural engineer involved

Attached are a few pictures of exterior. I will also attempt to upload interior pics too. I have attempted to contact a couple structural engineers but we live in a rural area and have not had any luck finding one available.

Posted By SIP Problems on 07 Dec 2016 07:14 PM
Attached are a few pictures of exterior. I will also attempt to upload interior pics too. I have attempted to contact a couple structural engineers but we live in a rural area and have not had any luck finding one available.

unfortunately looks like a failure , you need the engineer to assess in person

Do you have original structural drawings stamped by a Professional Engineer(PE) like a PDF you can post, or a section through the damaged area and a dimensioned floor plan showing where the damage is occurring and roof planes? It appears you're having deflection issues based on incorrect spans the PE may be liable for.

Before you get too much further, have you taken the contract you signed to a construction contract law attorney? Since the home build occurred in MO? that is where it has to be litigated. The PE should have errors and omissions insurance if you have not exceeded the statue of limitations for this type of contract.

Anyway, EPS nor OSB is not that good in deflection or elasticity...The condition here is called plastic deformation or permanent deformation.

These are the things the SIPs industry don't want you to know and no most do not stand behind their products. Most foam or OSB mfg don't so why should a panel. You built your home out of junk, sorry you were mislead. There will be other issues I won't get into.

SIP Problems,
, will need a PE that specializes in construction defects ,most likely will need to do "destructive testing" ,
in other words will need to cut out a section to see what is going on
you may not even have a product defect, it could very well be an installers defect , or they might be exceeding their span limitation,
but we can't guess looking at pictures
you need an on site inspection by a PE before you can take any course of action
this forum will have many opinions, like elbows we all have them, and they will have you running around like a chicken without a head
I get calls on many SIP issues from around the country, but unfortunately if I can't visit the site , I can't render an opinion.
the local projects I visit , I can usually determine what the issue is
but I can tell you this :don't expect the builder, engineer or MFG. to help much , they usually all run the other direction.

Morrie, I've been doing structures engineering for over three decades. Chris is the right, some panels may be flawed since it appears to be localized and since they and the rest lasted 15+ years it points to a localized issue perhaps. I was wanting to see a floor plan or section cut to see if this house is symmetrically loaded like an A-Frame. Lets hope that is not the case since the rest of the panels may be on their way - it's called reaching fatigue life short lived in this case and this design. To know that before you hire and spend more money on a PE that will do the same, a good one, ALL the panels have to be inspected since you may not want to dump money into a section when the rest are on their way.

They forgot to tell you that their design had little history. A PE signed off on this design they would be the first to talk to. Most do not do fatigue calculations(life cycle) since there are no non-destructive testing mfg requirement nor SIP history. Instead we use large factors of safety on the order of 2Xs what is needed that puts large weight on structure and foundations. I think we assume the foundation is not causing this, you'd see that in walls, windows, doors, etc.

More details to help educate you,

EPS has a very low yield strength meaning where it deforms and will not return, around 10 PSI at it's max deflection (@ 10% deflection @ about 60 PSI at 5 5/8' thk). Once it exceeds that it won't return. An Engineer should use half that, which is very low for a 4' span or horizontal foundation it is used to insulate. When they make EPS the same mfg processes and binders determine it's strength. It should be unlikely some panels are flawed but it can happen in a lot/batch run or at the bond lines(where voids or delaminations did not get filled by the mfg,  infiltrated water or moisture) to the OSB which also adds to it's yield strength.

In comparison mineral board like Roxul IS board has 30% yield max deflection @ 700 psi compression. FOAMGLAS even higher. Great for horizontals and large spans.

What is more probable and inherent in this design people do not realized is mold, especially at the seams supported by the rafters where most the load is, or it can mid-panel....there has been many cases on the internet. Your corrective actions here begins by visual inspections, taking the shingles off the roof in the center of the bow to each rafter, just a small 2' wide area strip for now. If you see rot you don't need to hire an engineer nor go through the expense of destructive testing. BTW: We use destructive testing to develop structural properties, we fail the part in bending to obtain yield strength, limit load, and ultimate loads.....It is VERY expensive process using stress/strain gages, fixtures, lots of docs, over kill for you best left to the manufactures that should have done this. Instead, they throw their designs in the field and let people like you do it for them, unfortunately! 

Now you can see it really needs to be litigated and a stop put to this design. You have another that has had the same issues there may be others for a class action suit. Let the courts decide who is at fault. Difficult for a business to run from liability law. If you decide on this path, talk to an attorney first.

Hope that helps....Your situation is bad, it won't be cheap. The EPS has split/cracked, infiltrating moisture/water/mold/rot, will continue as you see more roof loads(snow, etc) and can ultimately buckle failing the roof. Thats the popping sound. Framing over this with 2x8s is a bad idea won't stop it....You may end up eating away a negative margin of safety in the walls and foundation, like the roof may have been designed to. You'd be better off less risk in the long haul removing all the panels, decreasing the spans to allow for another insulation method. You can do that yourself, with a GC, following code, no expensive engineer. Besides, if you're already having difficulty finding a PE finding one that specializes in SIPs repairs in unlikely especially with it's lack of history and documented standards/structural properties.

I recommend you refer to this forum topic. http://www.greenbuildingtalk.com/Forums/tabid/53/aff/5/aft/83955/afv/topic/Default.aspx

Here is another link to refer to. http://www.energyvanguard.com/blog/59518/A-Building-Enclosure-Double-Disaster-Control-Freaks-Missing-Again

OMG! Great links for my failed building library, thx. The only blog I have ever written that received lots of hits was two years ago we production managed in part and I was on site, a $20 million commercial Timber SIP wrap, metal roof on water & ice barrier, no cladding vents other than house wrap that is usually not enough. It's not just about throwing it or a "gap" there has to be air flow in that gap at a certain CFM verified. I predicted SIP would fail over a 25 year life max in wet climates, there was plenty of evidence already now more. This architect did not know what he was doing. Today's US architects are more about art and space management many are not degreed engineers rather call themselves "designers" ya right try computer jockies at the home level and certainly not fluid dynamics. PEs specialize in Structure, have their hands full. In wet climates they need to utilize inputs from fluid analyst most do not.

I'm just amazed how people spend $100s of $100 of thousands of dollars or millions leaving home designs and trust in the hands of manufactures, builders, and contractors, DIYs, that have for the most part any knowledge of building physics and chemistry. Now we have the internet where ill-advice is all over the map not based on sound material properties or fluid dynamics, more on guessing like the threads above.......Then we have the "advisers" $ experts" with a database full of sponsored materials to promote.

What a mess!

Here is some more great information regarding OSB Sips for the Fraser family. http://www.homeconstructionimprovement.com/cold-roof/ and https://www.youtube.com/watch?v=txhzL5FC8-A

I stopped watching that video half way since the guy is full of it and what I mean by the unqualified should not be doing fluid dynamics. You just throw throw any cladding gap up there(eg: 3/4") and hope it has the right flow/CFM, and if the sorption rates of the materials are not right the gap is worthless. OSB sorption rates are very low it is junk!

Polyurathane Foam(SPF) & families stand alone have been under investigation by the EPA for quite some time:

https://nlquery.epa.gov/epasearch/epasearch?querytext=spray+polyurethane+foam&typeofsearch=epa&doctype=all&originalquerytext=spf&areaname=&faq=true&filter=sample4filt.hts&fld=&sessionid=4A824C568DB04D2ED0436BE91626F5B6&referer=http%3A%2F%2Fwww.epa.gov%2Fsaferchoice%2Fflame-retardants-used-flexible-polyurethane-foam&prevtype=epa&result_template=2col.ftl&stylesheet=

Sandwich it between OSB skins is asking for trouble no clading gap will solve.

Here is a SPF nightmare that put one family out of house and home, caused personal injury I hope they won a big lump sum in court, a huge expense: SPF NIGHTMARE!

I advise the Fishers consult Dr. Joe. https://buildingscience.com/users/joseph-lstiburek