HELP.... My 4 year old, polyurathane roof panels are collapsing/sagging on the top. My roof has a slight pitch to the back. The underneath side looks ok, but the roof has dips and low spots forming over 70 % of the building. Water stands up to 2.5" deep and 4' long in the center, of 2 panels. My panels are 4' x 12' and 6.5" thick. The panels have 1/2" black board, then EPDM rubber roof on top. We have been studing sips for years and this is our first building application, but have never heard of anything like this. I fear the worst !!! Please Help. Thanks in advance.

I am not sure if you have water damage in the existing roof system. If so, you probably will need to remove the roof panels and replace it with new panels. If there is no significant water damage to the roof structure you could probably get away with building new panels with proper drainage channels on the existing structure. If you contact Polycore Canada (1-877-765-9267) they can provide you with replacement panels, or tapered EPS/steel panels to go on top of your existing roof. What ever you decide to do, make sure the water can run off the roof so that you don't have the same problem down the road.

You have to do some forensic work and find out what is going on.  Was the roof constructed with not enough of a slope so the low spots were there originally or did this develop over time?  If it did develop over time what is the reason?  You stated that the panels look fine from below.  Is there any sign of water penetrating the roof deck?  Was the roof job such that it allowed water to penetrate and the weight of that deflected the roof?  Once you know the reason you have the problem then solving the problem becomes easier.

Ponding water can cause enough weight to be put on a roof that it will deflect more which will allow more water to pond putting more weight on the roof which will allow it to deflect more setting up a bad situation.  I would talk with a competent architect or engineer before proceeding with putting anything else on top of the existing roof to make sure it can handle the extra weight. 

Thanks for the replies : We do not have any leaks. The black board that goes down before the rubber roof is installed, is still hard, it gets mushy when wet. There is 6 inches of slope to the rear, and until this problem no water stood on the roof. The panels are attached to wood plates that are bolted on top of metal bar joists. All aspects of the construction were engineered and passed by both panel supplier and local building codes. ( my local inspector said if there was a tornado and he was close by, he was coming to my house ) I think this is a break down in the foam itself or it was injected into the panels improperly. Let me say this to anyone looking to build with panels.... I feel certain this is an isolated case, I did alot of reserch before chosing this type of construction and think its a good way to go. My panel supplier was aware of the original 2 panel failure, but I have not informed them of what looks to be a total failure of the entire roof. I'm sure manufactures read these forums and I had hoped someone would have a repair idea, but with no replies... a total replacement must be eminent. As far as doing a core sample or inspection into a panel, I was advised not to at this time. We are in a holding pattern for options and more info. Thanks for reading.

hcci;

who advised not to core? I would probably do that immediately to determine what is going on. I would also get the mfg. involved as soon as possible to make a claim on the warranty

I'd like to know where you are located and who supplied your SIPs. Do you mind sharing that? You can email me at [email protected].

Posted By hcci on 04 Nov 2009 08:55 AM 
As far as doing a core sample or inspection into a panel, I was advised not to at this time. We are in a holding pattern for options and more info. Thanks for reading.

At this point the only way to determine anything is with destructive testing from above or below

Posted By hcci on 04 Nov 2009 08:55 AM 
I think this is a break down in the foam itself or it was injected into the panels improperly.

It is a good testimony for EPS cores that can be seen before they are laminated, with polyurethane you never know if the core is fully injected, if the mix was proper, if offgassing is blistering and seperating from skin and if shrinkage is occuring.

We've used urethane for over 10 years and are dealing with our first failure. I'm a firm believer that 99.9 % of panel issues are installation problems, but we have roof panels that have collapsed. I'd like to know if there are other cases and if they are from one supplier. Anyone out there who knows of similar failures?