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TOPIC: Ice Buildup

Ice Damns

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I have had it with ice damns. Not a single thing more I can do with my asphalt shingle roof and ventilation to prevent them. If I get a metal roof, will they go away?
Guest User

2/20/2003
Your ice damming problem is probably mostly a result of an improper roof assembly and asphalt shingles are most vulnerable to let water in in this condition. Installing a metal roof alone will not cure the problem however installing one in a certain way will help you treat the symptoms. I would need more information to better identify your problem however if you have an older home that has had an insulation upgrade then the attic has lost its ability to breath. In older homes there is typically no air barrier installed under the plaster or drywall to stop warm moist air escaping. When it hits the attic (if you have one) and it can not ventilate out it heats underside of the roof material causing the snow tomelt which runs down and freezes when it hits the cold overhang of the roof. Take the opportunity of installing a new roof to correct some of the deficiencies. Remove the old roof and install a new metal roof on a strapping system that allows air to move up the roof. Use a good quality underlayment and along the eaves and valleys use a peel and stick ice and water shield. Depending on the system you chose there are a number of venting closure strips or intregal system details that allow air in at the bottom and out of the top. If you have an attic, ventilate it as well at the same time. Then I would look to stop the heat loss in those areas. Remove the baseboards and caulk the joint of the drywall to the ssubfloor. Remove the window trim and foam the joint in with a spray canister. Remove the light switch and plugs and foam through the holes in the box to seal them up. Then paint the room with at least two coats of a high quality oil paint and reinstall the trim. This will stop the air loss. Contact me directly with more details on your house and I can help identify it further.
Allan Reid
Dura-Loc Roofing Systems, Inc.

2/21/2003
Moved into our new home July 2001, southcentral Colorado. More snow this winter. Snow/ice accumulating in north facing valley. If it wern't leaking, would you recommend I do anything about the accumulation. It is getting under the roof panels, running out/icycles on underside of panel, even some leaking from soffit (2' overhang). Roofer said it's to be expected, that's why we install ice/water shield in valleys and perimeter. Claims he instaled 3 runs of overlapping 36" wide ice and water shield in valleys, 3' along perimeter. If properly installed,should I see water/ice running from underside of paneling? Should I install heat cables in valleys/perimeter? Am I better off with roof mounted snow stop or let the snow slide off. What about gutters? We want to plant beneath drip line, can't do it without gutters but I'm afraid snow will rip gutters off if I don't use snow stop. If I should use heat cables, can you provide me with recommended metal roof method of attachment. Would you recommend a cable manufacturer. Appreciate help Jack
Guest User

3/3/2003
Snowguards (snowstops) serve the purpose of holding the snow on the roof enough to prevent great slides of snow and instead to cause the snow to slide in smaller chunks. Due to the damming problems you have had, I would not suggest doing anything to impede the snow, particularly in the valley area. A cold attic is the best way to stop ice damming with any roofing material. This consists of strong insulation on top of the ceilings and good airflow through the attic. Usually the best way to get the airflow is a combination of ridge vents and soffit vents. Heat cables (heat tape) in the valleys and over the overhangs can help to melt the snow and ice and prevent damming. If you use heat tape and later install gutters, you need to line the gutters and downspouts with the tape too. Otherwise, the melted snow cannot run off. I know that Raytehon used to make heat tape. I think they have maybe changed hands though. I do not know of any other manufacturers. There are various clips and even adhesives I believe which can be used for attaching the heat tape. The best method for your roof would have to be determined after consultation with the heat tape supplier and the manufacturer of your roofing. It depends a lot upon your roof design. The use of the ice and watershield is designed to prevent water that does get through your roof covering (whatever it is) from reaching the roof decking and getting inside the home or overhangs. It sounds to me like something is up and the water/ice is getting bast the ice and watershield. If this cannot be alleviated through creating a cold attic, then the roofing may need to be removed and the underlayment inspected and replaced. To answer your very first question: No, I personally do not suggest trying to remove ice and snow provided the roof system (roofing material, ventilation, and underlayment) is functioning properly.
Todd Miller
Isaiah Industries, Inc.

3/4/2003
I have a chalet in cold snowy NH. We have no insulation on our roof just 2 layers of shingles. We have a 3 foot overhang and because that part doesn't get heated on the weekends and the rest of the roof does we have created ice dams. we installed the electric heating coils and that still didn't stop our roof from leaking into our house. Will a metal roof stop all of the leaks? And can we insulate the metal roof as well.
Guest User

3/11/2003
I have a chalet in cold snowy NH. We have no insulation on our roof just 2 layers of shingles. We have a 3 foot overhang and because that part doesn't get heated on the weekends and the rest of the roof does we have created ice dams. we installed the electric heating coils and that still didn't stop our roof from leaking into our house. Will a metal roof stop all of the leaks? And can we insulate the metal roof as well.
Guest User

3/11/2003
The situation you currently have with melting snow could also happen with a metal roof. The best solution to ice dams is to create a cold and ventilated airspace between the roof deck and the insulation. Whether that could be done on your chalet would be a good question to pose to a structural engineer or experienced building contractor. That said, metal roofs can help alleviate ice damming and the effects of damming due to to their relatively smooth surfaces which encourage ice and snow to slide from the roof and also due to the interlocking nature of many metal roof panels.
Todd Miller
Isaiah Industries, Inc.

3/11/2003
I have a house in Breckenridge, Colorado at 9,000 feet and have a metal roof that has been on for 10 years and we are very happy with it. However we do get snow/ice accumulation (18-24") and sudden discharges on the north side over the deck/spa area when a warm/sunny day comes in. It has broken the deck railings the last three years. During this last winter we had more acute drops and accumulation on the deck. I would like to gutter/heat tape the area. What is your experience and what vendor/products do you recommend ?
Guest User

8/14/2003
I have an 9 year old cathedral ceiling house with asphault shingle roof 5:12 and 6:12 pitch. Construction is styrofoam trays & R38 insulation batting in the rafters, with plastic sheeting stapled to underside of rafters and then the sheetrock against that. We have removed the shingles on the north-facing roof and installed ice & water shield 3 rows deep (approx 9' up from softet). The roof has leaked from the first winter we moved in, down exterior walls mostly but also from ceiling lights and skylights. We are planning to get a metal roof both for the snow shedding capabilities and also the air-space that strapping will provide. So I believe I want vertical panels of some sort rather than shingles. But I'm quite confused about the difference between standing seam with clips, without clips, versus wider ribbed panels with exposed fasteners and without. Do you have any recommendations regarding the pros and cons of each? Which one offers a more "water-tight" installation? Is there any difference in paint durability from one to the other (because one is cold form on site AFTER painting, versus factory extruded and THEN painted)? And by the way, what is oil canning? Thanks much!
Guest User

8/15/2003
First is that if you are getting ice damming then there is heat loss and or a ventialtion differential where the overhang is colder than the roof over the home and melted snow from the heat loss and or the sun runs down and freezes at the eaves. Heat tape will help elliminate this and I believe most do not harm the finish. You can also purchase snow retainers that will help control the avalanching. I strongly recomment that you contact the manufacturer of your roof and get their recommendations as each product and installation have certain sizing and spacing requirements.
Allan Reid
Dura-Loc Roofing Systems, Inc.

8/19/2003
We have seen this all to often where attention to detail is not there in vaulted ceiling assemblies. You probably have a combination of heat loss and lack of ventilation. The air barrier inside should have been sealed with caulking at all joints and penetrations. Check around all plugs and light boxes for air leakage. There are ways to retro seal these. As well you may have gaps in the insulation. The new code calls for a minimum of 1" of air space over the insulation and the styrofoam trays don't always provide this especially in longer runs. Check that you have clear soffit intake and ridge exhaust. A metal roof system can help you deal with some of the symptoms you have. make sure that you provide a clear vertical air movement. This may require strapping vertical and the horizontal. As to Standing Seam. This is typically a commercial system that has floating clips for long runs to deal with expansion and contraction. In shorter instalations fixed clips can do the job. After installation the seams are mechanically rolled shup and this type of system as excellant weather resistance especially on low slopes. You then may be looking at other vertical rib panels that are either exposed through fastened or concealed fastened. This depends on the look you want and sheet length. Both do residentail applications well. The big issu is to get the proper steel substrate and paint system no matter where the sheets are formed. Ask a G90 galvanized or a AZ50 steel substrate with a SMP or Kynar 500 paint system. Then once you choose a panel you can check with the manufacturer to check on warranties. Our member manufactures must offer the above systems. As to oil canning, vertical rib metal roof is produce from coils of thin steel and then roll formed. The nature of coiled steel and the manufacturing process can create certain stress across the coil and minute length differentials between the sides and centre of the coil. When it is roll formed in certain profiles certain waves can be seen in the flats. This can be made worse by improper attachement of the sheets. Choose a panel from our members and it will help ensure you get a quality roof to MCA standards.
Allan Reid
Dura-Loc Roofing Systems, Inc.

8/19/2003
Allan, With all due respect, you guys are the experts and the metal roofs with the ridge rows and the external screws, seem to be fairly standard. Why can't we get a specific recommendation or recommendations so we can further research it on the internet, rather than a response that demurs to a risk of infringement of a competitor company (by saying consult your manufacturer) ?? There must be some block or de-ice systems that have a longer history of success or some new approaches worth researchimg. As experts, point us in the right direction rather the stock answer of going back to the manufacturer. In my case the manufacturer responds that this is not his area of expertise (indicating one should seek counsel elsewhere). Bill
Guest User

8/21/2003
I am building a new house in the mountains of Washington with a foam core roof that should have an R48 insualtion value. All my neighbors have problems with their roof edges and especially gable valleys tearing out. How do you construct the valleys so they minimize tearing? I saw your suggestion to use strapping. How does that effect the gable valley construction? I may install heat tape, but worry that it will be ripped off with the huge snow loads when they finally slide. The house will probably be completely covered with snow by springtime. The snow then slides and takes chunks of roof with it. Is it advisable to put heat tape between the roof and underlayment? At least the heat tape would not be pulled off.
andy leash

9/4/2003
Hi Andy, Your questions are a bit complex and hard to answer in this forum. If you'd like, please call me at my office and we can discuss things in detail. 1-800-543-8938 ext 201
Todd Miller
Isaiah Industries, Inc.

9/7/2003
As i once worked on a bit a roofing in my time my best option is to get a new ventillation roof with all the trimmings
Guest User

4/23/2010
get stuffed
Guest User

4/23/2010
Subject: Metal Roofs info Hello, I'm doing some research and wanting to know approx how many sq feet of metal roofs are currently existing in the United States, and how many sq feet were installed in 2009. Even a best guess would help. Any info you could provide or direction on where I might find the answer, would be greatly appreciated!! Thanks
Guest User

4/27/2010