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TOPIC: Insulation Concerns

Open Porch Metal Roof, How to eliminate dripping, frosting , heat and noise?

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I have a deck off the back of my home with a metal panel roof. The roof is attached to the wood rafters and is unfinished so I am looking up at the back of the rafters and the bottom of the metal roofing panels. When the temp and humidity is at the right combo it creates condensation on the back of the metal and rains on the deck off the roof. When the temp and humidity are again at the right point it forms frost on the back of the roof and snows on my deck. In the summer the deck gets direct sun which is why we put a roof on it, with the roof it's like being a chicken in tin foil on a barbecue, the heat becomes opressive. When it rains the noise from the rain on the metal is so loud you cannot sit in the den which leads to the deck and hear the TV if the sliding door is open, which is another reason for roofing the deck so we can have the door open all the time for ventilation as we don't use A/C. What are my solutions to these problems? i have been told insulation and a ceiling but what type of insulation? I am leaning towards vinyl for the ceiling for appearance, cost and low maintenance but don't know what insulation to use. This roof is a shed type, low pitch over 2x6 rafters.
Guest User

5/29/2006
I am sorry about the problems you are having. The roof panels should have been installed over solid decking and underlayment and them, if desired, a pseudo attic space could have been included as well. Who installed the roof? Was the roof installed in keeping with the manufacturer's recommendations? I supposed there are other attempts at a "fix" that you could make but ultimately I suggest re-doing the entire thing. I am sorry to be the bearer of bad news. As one of the most experienced manufacturers of residential metal roofing in the country, I never would have suggested this type of application. Todd Miller
Todd Miller
Isaiah Industries, Inc.

5/29/2006
This is simply a shed type roof over a deck. It was installed by a local contractor and is just like the thousands of others that are built similarly. The roofing is attached just like you would attach it when building a shed or a barn. I've never seen any with solid decking or underlayment, just rafters, strips and then metal.
Guest User

5/29/2006
I understand that and, in my experience, they are all wrong. Sorry. Now, some of those systems do have insulated panels rather than just sheets of roofing and that is different. There is no way, though, to turn sheets of metal roofing into insulated roof panels. Condensation occurs when warm moist air comes in contact with a cool surface. Your metal roof is cooling down quickly during the evenings and then condensation is occurring. I certainly would look to make sure that you do not have any unnecessary sources of moisture or heat beneath the roofing and eliminate those if you can. I do not know if you have space to do this but if you want to build a ceiling and then put a vapor barrier behind that and insulation, and then either entirely close off the resulting airspace between the insulation and the roofing or make sure it is extremely well ventilated, you may remedy this situation. It won't be an easy project though and, again, I am not sure you have the space for it. Okay, one other option, you could have someone spray roofing foam on the back of the pabels -- probably 4 - 6" of it. If they do a really good job, that might eliminate the problem but I cannot guarantee that with expansion and contraction of the metal, they foam may delaminate from the metal at some point. I hope I have helped some. I am sorry I am not more encouraging. I am not so much frustrated, I guess, with contractors who do things like this as I am with other manufacturers who do not take steps to make sure that their products are not used incorrectly. I perhaps vented that a bit here and I apologize if it comes across as mean-spirited. I am just frustrated. Metal roofing is great stuff but it must be used properly or else problems like this occur and they end up being black eyes for the entire industry. Todd Miller
Todd Miller
Isaiah Industries, Inc.

5/29/2006
I have a shop with the metal installed the same as mentioned here. Wondering if we can use rigid foam insulation between the rafters and then poly over the foam facing the inside of the shop.
Guest User

5/30/2006
As long as you can get the vapor barrier completely sealed, that would probably be a good choice. Todd Miller
Todd Miller
Isaiah Industries, Inc.

5/30/2006
I understand your frustrations. From reading these boards I guess you can see the frustrations of the people that are paying for these poorly done jobs by professional contractors. It's not just the metal roofing, I have had problems with cement finishers, brick masons, and other "professionlas" I have hired. What if I remove the metal roofing. Then sheath the roof with plywood or OSB board, install roofing felt and then reinstall the metal roof? Would this be acceptable?
Guest User

6/4/2006
Unless you have a horrible moisture problem in the area below this, that should take care of things. Some metal roofs may allow you to install a rigid insulation board between the deck and the underlayment. You may want to check with the roofing manufacturer on that. If you can add insulation to help prevent cold transfer from the roof into the decking, that would be helpsful. Todd Miller
Todd Miller
Isaiah Industries, Inc.

6/5/2006