Help?!? Metal roof condensation

I need help. I applied a elastomeric acrylic roof system over a metal roof and now its leaking. Does NOT leak when it rains. But on clear cold days it drips. Anyone here have experience with this?

---Awhile ago there were some big lawsuits from condensation on metal roofs. The owners sued the roofers who sued the architects who sued the contractors who sued the landscapers, etc.. ---The roofers claimed they followed the specs. The architects said they followed the books. The contractor claimed the roofers should know better. The metal manuf. said nobody followed their specs... ---The solution is to seal off the ceiling from the building's moisture thus, ending the condensation. This is done with plastic vapor barrier and caulking all penetrations. It has to be tight where no building air can reach the metal. I believe there are companies that do just that. Also any wet insulation has to be removed. ---I would think an interior solution would be much cheaper than a new roof, etc. ---Also insulation pushed up to the underside of the roof is almost always trouble. It traps moisture which then condenses on any cold surface. I have seen several homeowner projects where they tried to add a room in the attic. They rolled insulation between the rafters and then sheet rocked the ceiling. A few years later all the roof deck started to rot because of all the water trapped between the insulation and the deck. The water vapor goes right through the sheet rock and then gets trapped. I know of a roof right now where the deck sags about 1-2 inches between the rafters. Replacing it is going to be ugly. Even ridge vent won't help if the insulation is too tight for the air to flow. ---I once saw a commercial building where they had an open ceiling but pushed insulation up between the TGI's. This was a wearhouse and I think the TGI's were 16 inch. It rotted out the TGI's and the entire ceiling decking and roof had to be taken down and all the TGI's replaced, then the deck and then reroofed. Fortunately the glulams were still OK but they were starting to go as well. That cost over 100k. It would have been far cheaper to have no insulation and a higher heating bill than to save on heating and get nailed for a huge repair. Insulation can create as many problems as it cures.

Lanny

I just submitted a proposal of like spec. on a metal roof structure.....Haven't heard from owner...Mor'n likely, they'll have someone smear chit all over it.....

Kingnear,

Mulehide is the privately labelled line of products available exclusively through ABC, in effect making ABC "the manufacturer".

This is the primary reason I try to avoid any product that is private labelled.

A new metal roof may not really solve your problems either. If you want to discuss this email me at MikeAtHRI@aol.com and I'll give you my phone number.

There's no preview of my uploaded pics, but I think these ones are from a metal recover. We'll see after I save the reply...

I'm not so certain it is a manufacture product issue kingnear. From what I've read it is the building interior issue.

B) :) :) B) Deep Down In Florida Where The Sun Shines Damn Near Every Day

Thanks kingnear, interesting read

" Does NOT leak when it rains. But on clear cold days it drips."

I'm not sure quite what to make of the 'clear' part, but it certainly sounds like a condensation/ventilation issue to me.

On another note... I am very disappointed in the Manufacturer with the support they gave us (or lack thereof). We used Mulehide products, through ABC Supply. Now ABC is our main supplier and have NOTHING but good things to say about them and their associates. But Mulehide is a subsidiarity or sister company or something. We looked at other products like Conlklin and Sherwin Williams, but went with Mulehide because our past relationship, and we've used alot of their EPDM product. Once we bought the equipment but before we landed jobs we had a company rep come out and demonstrate how to install the product. It took about 2 hours. And most of that was how to hook up and clean out your equipment. Every time after that we had a problem they (customer service) would say consult your application manual. Everything you need to know is in there. Can you send a field rep out to show us how to do this or that? I'd say. No. But we can do an inspection for you if you pay $200 and sign a waiver that we're not liable for anything. "What the??!!??!!" At the beginning I tried to get certified, but they ho hummed about it and dragged their feet and never got me paper work. After this last project I decided to get out of it, and my partner (install guy) quit. I've had to butt heads with manufacturers before, but when they won't even help you to install and back up their product...I don't need those head aches.

No, Im still here. Was gone for a couple days. Since I posted my question I have got some good info. What you said Mike substantiates what I heard from a local engineer and what I've been reading. Just a quick history of the project: We did the project in August. At the time there were a few leaks here and there, hence they called us to install a coating. We've been installing these for about 3 years. The building did not have any venting previous this project. The pitch is about 2/12 over metal perlins, cathedral ceiling, with blown on cellulose insulation on the ceiling (16"). The building is 150' long, but the last 50' is a newer addition and has large fiberglass batts on the ceiling instead of cellulose. This section does not show signs of leaking. The customer understands its not my fault and that I could not have known that we would create a problem by installing a coating. Nevertheless, they have millions $ of equipment getting dripped on. The number one question they want to know is why didn't it leak before if they didn't have venting then either. Did the panels have just enough air leaking through the seams to allow for venting? 3 weeks ago we added a ridge vent and bottom vented closures, but the attic space is only about 4'x2' by length of building. But with the cellulose being right up to the panels I dont think that will help. I like Mikes idea of installing a vapor barrier over the cellulose on the ceiling to stop the moisture from penetrating the insulation. Otherwise I could be looking at installing a new metal roof system over top in the spring. $$$$

kingnear disappared.

Is there any kind of ventilation to this roof? First thing that comes to mind is that you have blocked it.

One answer to this problem is to install 2 inches of foam over the roof then use coatings to prevent the sun from damaging the foam. 2 inches will give you enough R- factor [R-14]to stop the thermal transfer from the exterior to the interior. If you have condensation problems and you simply coated a metal roof with a white elastomeric coatings, you have magnified the problem because a white reflective roofing reflects the heat and the roof stays colder longer allowing for a longer condensation period. This being said I believe roof Coatings to be a great value to the building owner. Here again it is all about preparation of the roof BEFORE you apply the Coatings System. I install elastomeric coatings manufactured in Minn.by Conklin. We can not coat every roof and the contractor needs to KNOW where they can and can not be used. I would suggest 2 inches of foam and Coatings.

Thanks for the info wywoody. Its very interesting, looks like I'm gonna have to study more. I think my point is still valid but maybe I was off on the pyramid subject. I still feel its proven that stacked stone, uncut stone to be even more specific, is the absolute pinnacle of building technology. Even though in my short life I have witnessed so much concrete failure I have also torn off a 120yo chimney cap in new jersey made of concrete that I threw down three stories and I still have it completely intact. I have observed that the concrete is a very different mix than what's common today. My guess is that it is a much more organic mix than todays but that's a guess. I really appreciate thinking people wether I agree with them or not. Thanks again for the information.

You're right, Tom. Sometimes I try to instigate lively conversation when none is warranted. Whether the pyramids were the greatest building innovation in history or just a blownup version of what any 2 year-old can build with building blocks-it makes no nevermind to me.