Sounds like the builder did not foam seal the spline joints, this could be a potential problem if you are in a cold climate. as the warm air will condensate at the joint

Mr. Kavala is most likely correct. The panel joints weren't sealed properly.

This doesn't sound like a panel problem, rather it sounds like an installation problem.

No offense, but it sounds more than just lack of foam. I'm no expert, but how is foam going to prevent "buckling"? Is this buckling of the shingles due to the panels lifting/translating from each other? And if this is SEEN from ground level (as opposed to on the roof), I would think the deflection is rather large for the eye to see from several yards away.

I can't imagine SIP homes settling more or less than stick. I CAN imagine the foundation settling TOO MUCH due to lack of attention from the foundation designer/installer, though.

Point taken. However, if warm moist air is allowed to escape through the panel seams, the roofing felt and shingles above can become deformed. Even worse, the top layer of OSB can start to rot. Also, wet OSB tends to expand.


I guess that the biggest clue is this statement:

How does one foam seal the seams when the seams are abutted tight together during installation; moreoever, what's the solution, now that the shingles are in place...a complete tear off? Ouch!!

C.G.

Here's another head scratcher, regarding the proper sealing of panels, esp. roof panels. We sealed all of our INTERIOR panel seams with rubberized butyl tape (provided by Fischer SIPS out of Louisville, KY) and have noticed that frost on the roof panels doesn't accumulate on the seams either; however, SO FAR, the shingles are OK (installed NOV05). Furthermore, all of our seam splines were sealed with Fischer SIPS's specialized version of "Liquid Nails".

C.G.

Chris,
What type of splines were used to join your panels. If you used 2x's, which is fairly common for roof panels, the problem is most likely caused by differences in R values of the wood vs the foam in the SIPS. A 2x8, for example, has a much lower R value than an 8" SIP. It will transmit warmth to the shingles much more so than the foam. Therefore, at each seam that contains a 2x, you will have the possibility of frost melt caused by the relative warmth of the wood vs. the foam. I have seen this happen in reverse, with condensation forming along the wood lines on the underside of roof panels in a home under construction in which the HVAC had been turned off overnight.

Wes's statement helps to indicate that there is more than one possible cause. You'll need to hire a professional to investigate the situation & the cause. That would depend on the type of spline used. Also, remember, that most SIP manufacturers recommend an 1/8" gap between the edges of the panels. After the panels are installed, your options are limited. If simple OSB splines are used, you could drill holes along the vertical panel edges and inject foam.

Yea, I think the roof is the least of the problems. I would think that repairing the drywall would be more expensive.

Wes and J.C.,

I don't mean to steal Miked's thunder on this particular message thread but I hope that my concerns and questions are akin to his. At any rate, we've 2x10's for splines in the roof and, so far, haven't seen any sheetrock issues to be concerned about but who knows what the future holds? Thanks for your input guys.

C.G.

As a structural engineer who has designed over a hundred SIP buildings and personally built several in the last few years I may have some insight into this problem. Many of the responses have been on track and the problem is with the fact that (2) 2x’s were used as the spline. Your comments are a text book example of 2 reasons why I NEVER use a (2) 2x spline.

First, the lack of frost at the spline lines demonstrates the very low R value of wood. One of the biggest advantages of SIP construction is the lack of thermal conduits (2x’s) through the wall. If you use (2) 2x’s every 4’-0” oc it is exactly the same as using (1) 2x at 24” oc (typical cheap stick construction). This will lower the overall wall perforamce of a 6” SIP wall from R23 to about that of a stick wall with batt insulation (about R12).

Second, as the building materials expand and contract significant stress is created in the walls and roof panels. The OSB skin can handle the stresses as well as lateral joints (nails or screws attached perpendicular to the wall plane). However, nails applied parallel with the wall plane will tend to pullout creating a gap between the (2) 2x’s at the spline. No amount of foam or mastic will stop this from happening. The joint tape helps because it will stretch and prevent some air leakage. (I have been in SIP homes under construction and you could see daylight through every 2x spline.)

The solution is to use SIP splines wherever possible. In roof s with long spans that require a little more structural strength, use TJI splines. These splines educe the thermal conduit from 3” to ¼” or less. They also eliminate parallel nailing and create two tightly attached planes to apply mastic or foam (between the spline and the OSB skin). This eliminates the straight line gap and forces any air movement around the spline and through the tight joints. IF you need to support a point load in a wall, use a 4x or larger instead of (2) 2x’s.

The question is how you can repair your problem. If you do nothing, hot moist air will continue to pass through the gap, cooling off and creating condensation, and the problem will get worse. The condensation running back down the gap and saturating the drywall is what is most likely causing the drywall failure. And as someone previously mentioned, the condensation is wetting the OSB, causing it to swell. It is also greatly reducing the structural strength of the OSB, and since the OSB is the structural material in your roof, it is a real concern.

There are two ways to attack the problem. First, since the drywall is ruined and mold could be an issue, I would remove the interior drywall, chalk the joint with an elastic silicon, and apply the SIP joint tape (which should always be used in cold climates), and drywall the ceiling again. Second, I would remove the roof shingles, sand down the swollen joists, apply an elastic roof coating such as “Snow Roof”, and apply two layers of felt and shingle the roof. This will be expensive. Good luck.

Brian

It appears you are suffering defects caused by poor installation. In my company we only connect sips in roof applications using osb splines, this prevents cold bridging, which can be a very major problem in locations where there is a high Temperature differential across the sip. The problem is not caused by the sip!!! it comes from the guy who fitted it!!!! Cold bridging creates Interstitual condensation and rot of the OSB, this cold briging can even come from Sipscrews passing right through the Panel, stick connections and I beam connections are notorius especially if there are loose fitting gaps around them. Look for black mold growth a nd small wet due patches. We also liberally apply MCPU Adhesive NOT SILICONE CAULKING, throughout the joint to ensure a strong tight connection. I have worked extensivly in Skandinavia and Austria, you should look at the lengths they go to to prevent cold briging, and cold spots and application of vapour barriers. One last point Building control in the UK will never authorise the use of shingles on our roofs. we apply a waterproof roofing felt, then counter battens and fix interlocking clay or concrete tiles. Even if a tile fails the water ingress will run down the roof betweed the battens on top of the roofing felt without making contact with the OSB Sip facing. You need a competant contractor in there immediatly to examin/ rectify this problem.
Dont accept a cosmetic repair, it will not work,

Here in the UK we have a no of BAND WAGON/ cowboy  Sip Makers usually cold store manufacturers who have come into this market in the last 2/3 years, they have no real knowledge or experiance of SIP BUILDING. yet if you look attheir websites they all claim to be the BEST , Experianced etc etc and they continually steal images and technical data.  Making as Sip is easy,  applying them properly is where the skill and most of all experiance comes in.

I am giving expert testimony on SIP Building Law suits here in the UK on all but 3 of the UK Sip Manufaturers/ Installers.
We have specialist Sip design companies springing up, claiming to be experianced Sip designers, these guys are not even architects or home designers.
1/ 2 years is experianced ??????? Not in my book
And I see their rubbish work every day
A  sad situation that  reflects very badly on to a fledgling Industry and is allready having to field unfair biased criticism.

You have some very experianced people and SIP Manufacturers in the US with years of practical experiance. I have seen numerouse postings from inexperianced people blaming particular manufacturers products, I know Premier, WInter Panel, Insulspan, there is absolutly nothing amiss with their product. I repeat most problems that occure in sip comes from the application. CHECK THEM OUT BEFORE YOU HIRE THEM

As concultantys in SIP Technology hardly a week passes without us being approached by a disapointed sip users in trouble asking for advise on such problems one job is a $2.000.000 plus house, with saging window aperturesand roof  ridge, somhow the cowboy who buili it, put it up without any building structural calculations. This unfortunate couple talked to my associates  but dismissed them as being too expensive, they chose a
"EXperianced " sip company from the North Of England 400 miles away in preference because the price was 25% lower!!!!!!!!!!!!!!!!!!.
This house now  needs to be torn down and rebuilt and the company is bust. and there is NO INSURANCE  was that cheaper?????

Something not to overlook is the interior air pressure. If your furnace is pulling in more air than it exhausts you will have areas that warm moist air is being forced through your exterior
envelope (cold climate conditions). A good SIP installer cannot combat an improperly ventilated house.. SIPs certainly perform better than most systems when in comes to air leaks, but no house is completely airtight. A simple fix could be to just run your bath fans more often (cheapest option). This will lower interior air pressure and actually pull (slightly) in dryer air from the exterior. Having air flow outside to interior (again cold climate) will dramatically reduce your chances of mold and rot in the exterior shell. One thing I have learned since working w/SIPs is that the whole house is a system; the shell and HVAC need to be planned and integrated.

Very interesting points, AVANT. A newbie like me can learn a lot from pointers like this.

My design (as done by a SE... albeit not that familiar with SIPs) has (2) 2x's at every joint (8'W panels) for structural reasons... I think. I never thought about the parallel nailing and pullout effect due to temperature & resultant contraction/expansion.

How about this... If you have to have (2) 2x's, how about screwing versing nailing those parallel scenarios? I'll ask my SIP guy about the TJI splines... and/or 4x stock.

Q: Are there TJI splines for roof spline applications comparable in strength to dimensional lumber? My SE spec'd dimensional lumber for my roof splines (I have 10".).

uncleho,

Nails and glue would help your situation, but you missed the point above. The issue is using dimensional lumber rather then an OSB or mini SIP for the spline. The problem is that some factories do not do testing of their product with splines other then dimensional lumber. And that is an issue because you will get more thermal bridging and losses the more dimensional lumber that is put in your cavity. As for TJI's, they are stronger then their dimensional counterparts.

It may be that your point loads require dimensional lumber, but it is more likely that you are getting dimensional lumber because the factory hasn't tested other connections as this is a big expense. In fact many point loads can be accomodated by a beam pocket in the OSB. If this is the case, you should talk to your SE about eliminating all the dimensional lumber. And if your SE does not have OSB or mini SIP connections, you might want to consider a company that does for the reasons stated above by AVANT.

According to the test results from my SIP supplier lumber splines in SIPs can support a larger roof load. However, when I design a structure, if TJI’s are not strong enough, I either shorten the span or thicken the roof panels. Usually this only occurs with heavy snow loads so a thicker roof panel is better anyway.

From a structural standpoint, lumber splines do NOT increase the lateral resistance of the wall (4x end bucks do, but not splines). The only reason you need vertical lumber in a SIP wall, as mmacgowa said, is for vertical point loads (beams or girder trusses typically) when their loads are significant. Most loads on a SIP wall can be supported by the panel only.

My SIP manufacturer performed the standard wall lateral test for their ICBO; which is made up of (2) 4x8 panels attached together with their standard spline (SIP type spline). I think most of the SIP ICBO’s use this same setup.

Hey Brian,

Sounds like you have a lot of good sips experience; may I ask you about an unrelated sips topic?

I have had General Panel design the sips package for my Northern Utah home, but it is really patchwork. Many more seams than I would like. 

Do you know a good company who can provide sips 9' by 24'?

  Then the crane does the work and we don't have to carry all these smaller panels around, plus the seams are minimized.

Thanks,

H. Ball

Likely, nobody. Sheets of Jumbo OSB are 8' x 24'. And, many manufacturers don't even use those. So, you are probably stuck with using 8' x 9' or 4' x 9' panels.

Pulte Homes uses 9’x24’ SIP panels produced by Premier for homes in the east (out here in the west they still use stick). However, they only make them for Pulte because they have to buy a complete train car load of 9’ OSB at one time. They do not offer them for individual projects. Also, the OSB guys cut the 9’ OSB from 12’x24’ OSB sheets (the largest I know about) so sometimes they have to pay for the 3’ drop. Premier is limited to 9’ because of their press size. As SIPs become more popular someone may start pressing 12’x24’ panels but I would not suggest you hold your breath.

It wouldn't surprise me to see Pulte have PBS(Pulte Building Sciences) start to actually manufacture the panels themselves. As they ramp up volume, it would only make economic sense. And, if they can manufacture prefabricated concrete basement walls(Think Superior Walls), they can manufacture SIPS.


I would be happy with 10' x 24'. Then we could have a 9' ceiling and still hang the joists from the wall.