Icy eves

Author: Dave
Date: 12.23.09 - 6:27am

(not computer RE related, but still a form of RE so...)

So Winter is back upon us here in the frigid north, which for many means its time to fight with those pesky icicles that grow on the roof and eves.

I bought an older house several years ago which suffers from icing problems. Over the years Ive tried several different remedies and talked with contractors to try to determine how to solve this problem. I found it odd that in the 50 years but this houses existed no one had ever a eliminated this problem.

It turns out that making an ice free home is actually a bit of an art one that I am setting out to master it least for this house.

The first year I didn understand its characteristics I let the ice build and dam unencumbered. I lost two ceilings that your witch was enough of a lesson for me. I guess I should have known there could be a problem when first I saw icicles creeping down from the soffit. Then when I saw an icicle or two dripping between the window panes I started really hoping for a thaw soon. Unsure what would happen or if I would get lucky and did nothing also I knew of no remedy at this point. Turns out I should have been more proactive either calling someone to get on the roof and remove the ice or to attempt to melt it off myself from within the house.

Over the years I have tried many things. The first thing I did was hire a roofing contractor to come and do ice removal. If youve never had to pay for the service let me tell you there are several methods they may use.

The first guy I got was happy to go up there shovel out some water chip at the ice a little with a hand ax and spreads salt for $75. This was a sham all the way around. I had drips again inside the house within an hour, additionally salt is bad for your roof its really not recommended he accomplished nothing but taking $75 from my pocket. He did this several times before I caught on.

The next contractor I hired knew what he was doing. He waited until a semi-warm day then sent a guy up with a sledgehammer. Note that this is not ideal its very tough on the roof but if you are literally already to the point of having interior house damage it may be a necessary risk. So he went up and the pounding been commenced. The house shook ice fell and by the time he was done there was not an inch of ice left. The problem had been effectively reset to zero.

Not wanting the repeat event, The next summer I had three roof vents installed and 4 inches of blown in insulation added to the attic. The same contractor performed the work and advised me on things to observe to help him determine what the roof system needed in order to correct these problems. He was a very wise man things that are very common sense but I wouldve never thought to look at. For instance after a fresh snow look at your roof and look for sunken spots in the snow that represent warm spots on the roof that is melting snow. Also look at the times that icicles form. Is it the sun melting the snow on the roof at the warmest times a day, or are there specific hotspots on the roof that are doing it.

if you have hotspots on your roof it could be several things. Maybe there is no insulation in a side wall and the heat is traveling right up a vertical wall with a lot of surface area and constantly hitting the same spot on the roof. Maybe you have a section with a cathedral ceiling where the insulation is packed all the way solid. In this situation the heat from inside the house is absorbed by the wall and travels straight up through the insulation. Where the insulation touches the roof hotspot develops. In this situation and air gap between the roof and the insulation is necessary. This allows the heat to dissipate into the air and travel along the slope of the roof like smoke over a piece of paper.

Now that I have been trained to look for these things I can start

experimenting with a remedies. First lets get back to management though. The next winter I was anxious to see what effect his steps would make. I can see mel spots around the fencing installed in the ceiling, so I knew they were working well allowing heat from the attic out. However I still had specific hotspots on my roof causing problems. I wasn quite sure how to handle them at this point so I needed ways to manage the ice build up. I bought a roof rake and every time it snowed I would make sure to remove the snow from these problem areas. It kept icing to a minimal status, but it was also a rather tedious job. If you missed the day you could easily have bad ice problems again. Ice melting and removal again became necessary. I would occasionally knock off icicles with a broom or throw a sock filled with salt on the eve to try to melt a channel. Finally I came up with a really good solution that could tackle even the largest of ice dams that I face. I attached a water hose to my roof Rake, then hooked it up to the hot water faucet that turned the water on and directed the stream right onto the damn it takes awhile bought within an hour or so you can have a dam removed without any damage to the house.

This year however I am trying to actually remedy the problem. A closet section with a cathedral ceiling has had half-inch foam insulation applied on the interior wall. So far it seems to be effective. Once I am sure that is all the area needs I will drywall it in. I also went up into the attic and dug the insulation away from the cathedral ceiling sections making sure there was an air gap as far down as a long stick could reach. The melting in this section of roof seems to be greatly diminished. It appears that there were actually three or four distinct mel spots in this section. The major one seems to have been eliminated which was caused by insulation packed solid with no air gap between it and the rough. The next melt spot in this section appears to be from hot air traveling vertically up through the side wall and constantly hitting the roof in one spot. Foam on the side wall was attempted and lessened the problem however it is not completely solved yet. I think next I will install several soffit vents to trying to enhance the airflow for these two rafters in the cathedral part of the roof. This problem spot is actually on both sides of the House where a dormer juts out for a bedroom.

The dormer roof is also a problem. It has been responsible for the worst of the ice damage so far. This year I installed fine if soffit vents along its length. I am not a fan of ladders but I was lucky to be able to install them from working inside the house through the window. (The upper window slides down) it appears to be lessened but I am still getting more ice than I want. Not able to physically observe the section of roof, I was not sure how to inspect it for problem spots. Using a cheap USB camera taped to a broom handle I was able to reach it out the window and observe the roof on a computer screen. It turns out that the side walls supporting the dormer roof are creating huge melt spots for the entire rafter length near them. I did not install a soffit vent for this rafter span, so that is my next order of business. Additionally I may have to crawl into that section of the attic to stuff some fiberglass insulation down between the studs for that section of wall to slow down heat loss.

The final section of ice problems is in the back where the last 4 feet of the roof line cut into the body of the House and form another cathedral ceiling like area. To make matters worse a bathroom renovation for some reason caused someone to block off several rafter sections at the top tightly two of these had a large ventilation hole drilled in them but the other four were sealed tight. Also someone had later packed the entire area solid with insulation not allowing any higher to escape. I dug out the insulation and cleared the vent holes as best I could I also tried to create an airspace as deep down as I could with a long stick. This area is still getting a fair amount of ice soffit vents will be required I believe, but that is a ladder job and not for me.

Hopefully this will be the year that I make this house ice free for the rest of its days. the contractor warned me that for some houses no matter what you do you will still have an icing problem. Hopefully Ill be able to solve this with passive solutions only, but if not I have arty purchased an expensive roof heating device from thermal technologies so that I never lose another ceiling again. One final note, the contractor said that heat tape is a poor choice because you have to always lead on or it can become overwhelmed and encased in ice. The thermal technologies device is heat tape inside a 1 foot wide aluminum extrusion. It is guaranteed to melt all snow and ice on within contact. While much more expensive (800 dollars for a 14 section) it allows you to only turn it on when you have in ice dam and it will remove it. This is much easier than standing outside for an hour with a hose and can be performed by anyone.

I will update this post as I keep working out the details on how to tune this houses heating losses. Hopefully the tricks and experience discussed in this paper can help others with their own icing problems.

Comments: (4)

On 12.23.09 - 6:55am Dave wrote:
One other tip. Those contactless digital therometers are pretty sweet tools for detecting cold spots on walls or to determine which walls are loosing lots of heat. Is it a spot? is it an even dissapation? Actually sort of fasicanating. While thermal imaging tools would be the coolest, scanning an area with one of these little guys allows you to build a mental map to visualize the same data in your mind. The Ryobi model i bought was under 30 bucks and worth every penny. (Also handy to find/and quantify the severity of drafts unders doors and windows, and is useful in the kitchen as well)

On 12.23.09 - 7:18am Dave wrote:
One more bit, I think i found another hot spot. House has a hot water baseboard retrofit, some plumber drilled through a closet door jamb to run a 120 deg hot water pipe. This jamb is built up with two side boards and a front face board. Perfect hollow duct leading right up between the two sides of the wall. Put a hot ass pipe at the bottom...and guess what? Lines up pretty well with a very hot spot on the roof (as observed from the ground had to line up exact spots) but i bet this theory leads to the solution of another intense hot spot. plumbers are not roofers..he probably never would have thought about it.

On 12.30.09 - 8:15am dave wrote:
Quick update, found 5 spots where the hot baseboard water pipe goes through walls. All 5 spots lined up with heavy icing spots on the roof. Good corrolation. I bought a pack of 4" round plastic soffit vents and a 4" hole saw and a couple batts of "handy insulation". Drilled into the interior walls just above the pipes, stuffed insulation in the stud vacity just above the vent and inserted the vent. Pretty easy way to go. I was thinking about drilling a hole above the insulation and spraying in Great Stuff..but the can says fumes are flamable and can cause flash fire. umm maybe not. Called a foam spay guy. He said he can spray a plug through a 1 inch hole (but not fill the whole cavity all teh way down) but he says its a min of 400 bucks to show up because its allot of setup and a 20 foot trailer. Need an alternative non flamable spray foam for one section of wall where i cant drill a 4 inch hole. Icing appears to be fairly well diminished, but since i didnt establish a reference point to a known undisturbed ice reference cant say for sure yet.

On 12.10.13 - 12:59am Dave wrote:
So the ice problem looks like its finally solved. The big step was installing heated roof panels from meltyourice.com. They arent that expensive when you consider the about of work they save and having to deal with the constant risk of loosing a ceiling due to water damage. They arent that expensive to run either, i dont even notice it on my electrical bill. The second step was to install a power vent fan in the attic. Keeps the house cooler in the summer, and auto turns on when humidity peaks to help keep keep the ice from forming during melt periods. Between all the steps above, I am finally ice free. That was a long and winding road!

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