I maintain a manufacturing facility that has a low slope,raised ridge metal roof. My issue is that we are getting a number of leaks at the low edge where there is gutters located. It seems to be leaking from the walls at the top. Would this be caused by the gutters filling up and freezing, thus creating ice dams? Should I remove the gutters to prevent this from happening? Any feedback would be appreciated.
James

James,
Please read all of my Ice Dam columns - there are several - to understand the dynamics of what is happening. You can't stop the ice dams, but you can stop the leaking!

I have an existing house and we have put a small screened in porch over the deck with a roof set on the existing roof...with enough elevation 1" or so allowing water to run down the existing roof and the new roof to run off on to the existing roof into the existing gutters. There is opportunity for snow accumulation to occur in the valleys of the new roof and existing roof to create possible ice damming. What about heating coils with a thermostat or am I wasting my money. Thanks.

Steve

James,
I disagree with the comment that you cannot stop ice dams. I have never had an ice dam on my house in Western Massachusetts and have fixe three older homes that had ice dams for years so that they will never have to rake snow again or chop ice dams. On one home that I reroofed last year there sits two feet of snow with no sign of an icicle or any melting. The solution is a little on the expensive side but if done in conjunction with reroofing is a must do to eliminate future ice problems.

I have ice dams on the east side of my house built in 1955 on a crawl space and am in central Ohio. I am wondering if these dams are causing the mold problem in the N. E. corner of my house where the gutter pipe is located. The mold is present on the bottom where wall meets floor. There are other corners that also have mold in the S.W. side of the house. Thanks

For James Williams: I am puttin on a new room on a 3/12 pitich in Michigan with ice dam problems. What did you do to corrrect the problem. Thanks Dixie Wong @ dixie@dixiewong.com

I have two questions regarding ice-dams and leaking, which I have now all the way around my roof.

1. I do have a 2 foot overhang (with exceptions of a bay window that extends out to directly behind the gutters). The rest of the way around the house it leaking out the soffit vents (icicles hanging outside many of them). Soffits are wood; no metal or vinyl siding over them. This has been occurring for a number of winters now, only this is the first year it has come inside (via the bay window and hence really caught my attention). Will the soffits generally dry out as this year they're all getting really wet underneath, or will they likely need to be replaced (when I get re-roofed and make sure I have the correct membrane under-layments)?

2. I've read that some of this leaking can be caused by the ice dams in the gutters causing water to back up and seep over the back top of the gutter and then down into the soffit. How likely is this the cause versus backing up under the shingles? Does this also need to be checked for proper sealing between the upper-back of the gutter and the roof - should the ice-shield membranes wrap down behind here somehow? Or is a gap here acceptable and rarely the cause of leakage?

Thank you very much!

Hi All, This thread has some very useful information. I have a situation that is a little different than the typical ice dam issue. I have ice dams on only one roof of my house. It is only one side of the garage with an 8/12 pitch, the back side. There is a finished room above the garage and the ice dam is forming along the small attic space next to the finished room. Now here is the catch. I have a steel furnace stack that goes through this space and out the roof. The heat generated from this stack is melting the snow and thus creating the ice when it reaches the overhang. The front side of the garage is fine, only the back side with the stack is the issue. The gutter, 25 feet in length, will fill solid with ice. The downspout will fill solid with ice. The furnace stack is on the opposite end of the gutter where the downspout is. The ice in the gutter just below the furnace stack will build up above the shingles. The soffit is vented aluminum the full length and the roof has a ride vent the full length. Without the furnace stack the roof would perform fine. How can I get rid of the extra heat generated by the furnace stack to stop the snow from melting? Rerouting the stack is not an option.
Thanks for your help.

Hello everyone,
My situation is this: I had a local builder put an addition on our house here in Central, MA. about 2 years ago. I planned on doing the interior finish work except for the insulation in the cieling (a man must know his limitations).

Anyway, the first year I left it as an empy shell because of a limited budget for the project. The interior wall that connected the new addition to the house was not opened, and that winter we got ice damming. It was not at the lowest edge of the roof but the entire roof!

The builder did all the designing and was informed of all my concerns. Needless to say I called him back and showed him the damage after a length, heated discussion and speaking with the building inspector he reluctantly came back to fix it. He told me he would pull off the shingles and put the ice dam membrane on the hole roof.

I, unfortunately for me, was not home when he came to do the work.

Needless to say, this year after doing all the interior work, got ice damming again. This time it has made stains all over the interior wall and new ceiling.

I am wondering if I should contact my home insurance or just get it fixed and send him the bill? Contact a lawyer?

Also, what should I look for in hiring a new contractor to fix this for good?

Ice Dams can be prevented! Remember a house is a system.
Most solutions that are perscribed to slove ice dams are simply temporary fixes do not eliminate the problem. An Ice Dam is not a roofing problem, although often roofers are the ones called to resolve them. They can stop the immediate leaking and are likely to sell you ice and water barrier, or aluminum or copper Ice shield. Neither of these prevent the problem they simply helps prevent leaks by providing a seamless material between the reservoir of water and the interior. That is not the solution! Ice dams are created when the snow on the roof melts from heat loss into the attic due to air leaks called convective losses, and thermal leaks called conductive losses. Stop the convective losses and reduce conductive losses and the problem is solved.
This is the type of work energy specialist, weatherization company, insulator, or someone who truly understands the issues, and will do a near perfect job at air sealing before adding additional insulation.
Air leaks exist in every house unless someone expended special effort to seal them. One does not normally think about these potential leaks or realize the damage that can be caused. To give you a sense of what an air leak is the next time your bathroom is nice, steamy, and warm, try this. Turn on the bath fan and with the back of your hand feel around the switches and outlets, you will find that the air is drawn into the bathroom through the any tiny hole, perhasps the slots in the outlet. The source of the air may be the basement, the attic, or the outdoors. When the air escapes a warmed house it contains moisture, called realitive humidity, the amount of moisture air can carry is realative to its temperature. Without sinking too deeply into this subject, let us just agree that, the warmer the air, the more moisture it can hold. As the warm air cools it must release some of its moisture, this is called condensation, hence the water droplets on the mirror or window after a shower. It is why we have frost on our windows after a cold night, the air cools as it approaches the cold window, and deposits its moisture on the glass, which will drip or freeze depending on the temperature. The condensation process goes on within a wall cavity and can cause serious issues.
If I haven’t convinced you probably are in denial, but for the sake of finishing this explanation, trust me there are leaks in houses, it is easy to prove and measure with reasonable accuracy.
There are three ways that air moves, stack effect, wind, mechanically. The one we will be concerned with right now is “Stack Effect”, this is warm air rising. It does this because warm air is more buoyant than cooler air, while warmer air rises cool air drops creating air currents. One type is called convective loops, a topic for another day, which we will ignore for now. The other type, stack effect, is the concern for ice dams. As the days and nights grow colder, the heat comes on and the air in the house is warmed up, warm air is more buoyant and rises to the top of the structure. This effect creates a high positive pressure at the top house. As the air leaks out it causes a negative pressure at the bottom of the house and for every cubic foot out a cubic foot comes in. Air leaks in or out of every hole and crack it can, around lights, fans, cracks in the plaster, switches, outlets, the attic hatch (is it gasketed and insulated), the joints between the top wall plate and the dry wall, some big offenders are, the chase ways for chimneys, plumbing, and electrical. The cooler air is dryer since it can’t carry as much moisture as warm air, then as it warms within the house it absorbs the home’s moisture, this is why homes become dry in the winter, air leaks. Not that old tale that warm air heat drys out the house. Back to the point, the air that is leaking out of the house is warm and will warm the bottom of the roof deck (sheathing), where condensation and frost will occur as it gives it heat to the roof deck.
The other thing that happens is that heat moves to cold, this is indisputable. Stand in a warm room with a few windows in it, the air temperature is 70, but you feel cold, why? The heat from your body radiates to the cold glass regardless of the air temperature and even if the window is the best money can buy your body at 96 to 99 degrees will lose heat to the window. OK, prove it to yourself, take a balloon, fill it with hot water, not too hot, tie the end off, the balloon represents your house. No matter how we turn the balloon there is not any leakage. Achieve this level of air sealing and you won’t lose heat by convection. However the balloon in your hand feels warm because it is loosing heat to our hand by conduction, assuming the water is above your body temperature. Let us take this a bit further, place a piece of paper between the balloon and your hand, hence insulation, now add more, a little insulation in ineffective, but if you keep adding paper or just put a book between the balloon and your hand you will no longer feel the heat. So if you put enough insulation in an attic you can substantially reduce convective heat loss.
Wow, now that we have finally learned the minimum we need to know to understand the solution to ice back up we can attempt to solve the problem. Air seal the attic absolute, think about our balloon, if we turned the house upside down, and filled it with water, would it leak? That is extreme, but if you do not have this mentality, you will not achieve your goal. Once that is done add thermal insulation, enough to substantially reduce the conductive loss. HOW MUCH, well the zone five international building code says R-38, but I say R-50. Unfortunately we have many structures build in a fashion that does not allow for adequate insulation at one of the most important locations, the area directly above the exterior wall. One solutions is to use some high R-value foam, polyisocyanurate, another is a two part spray applied high density foam. Great for use in this critical section to both air seal and thermally insulate, R-7 per inch.
There are yet a few details I need to address before closing out.
Attic ventilation is used to sweep away heat and moisture, which gets into your attic, the work we do is not likely to be perfect so some ventilation is still a good idea. The build ing code requires this although wwe don’t want to close the door after the hourse is out, so don’t try to solve the ice back up by just adding ventilation, it can have other effects.
Ice and water barrier is an asphaltic and or rubberized product used to HELP prevent leaks from entering the house by providing a watertight barrier below the roof shingles. These products add extra protection if one is installing a new roof. Ice and water barrier needs to be installed from the lower roof edge to a point that is two feet beyond the interior face of the exterior wall as a minimum. If you have ice back up it is likely to happen at the exterior face of the exterior wall, this is because of the air leaks into the exterior wall carrying warm air to the top of the wall and the thermal loss though the poorly insulated section where insulation tapers down with the roof slope is greatest here. Understand, the exterior wall is a colder surface and heat move to cold so there will be a higher heat loss in this area.
Clearing the snow from the edge of the roof can create another ice backup at the point the remaining snow ends. Let’s think about this for a minute, we learned that because of the heat losses the bottom of the roof deck warms and therefore melts the snow above from the bottom, this water runs freely until it finds a surface that is cold, which is typically at the exterior face of the exterior wall. Here an ice dam forms and grows as long as the melting water runs. If we scrape the lower section the reservoir is exposed and it freezes stopping the immediate problem, but the cold spot has now moved up the roof and with the right (or wrong) conditions a back up can still occur. A simple temporary solution is to take a pair or soccer socks or panty hose (guys, don’t use the new stuff find the old ones) fill then with some Ice Melt (potassium chloride), tie off the top, and lay it perpendicular to the roof edge. The sock will melt through the ice dam and allow the reservoir to drain, remember this does not solve the problem.
A roof with no icicles and snow on the roof is typically a well-sealed and insulated house. Never insulate without air sealing first and remember moisture is the enemy!
Now, just when you though you were off of the roof there is one more thing, the snow will now stays on the roof longer, and in a good (or bad) winter the snow may accumulate to a point, which will push the design limits of the building and action of another sort (shoveling) will be needed to resolve the issue.
Yes, I know why solve one issue to create another, because you will be in control of the situation and not driven by the midnight leaking roof, you will waste less heat energy, save money, and be more comfortable.
Always remember a house is a system and one must always consider the effects of each action taken.