Home Forums Hunting & Shooting Alaska Roof Ice Dams and snow load

Going to be a bad one this year, went down to Sterling with a snow rake almost 40" of settled snow was able to rake top 18" off the rest of Ice had to stay.

Back at home in Eagle River bad snow year, lots of Ice damming my house most of the roof is good tried to use snow rake but to much ice. Looking at bad houses in the neighborhood some have 10 plus inches of ice dams! 57 straight days continuous freezing weather.


House buying tip for Northern climates best to look at houses in the winter easy to see the problem houses! (Hot spots in roofs)

House with a hot roof


Snow load ice cycles just appeared last 2 days finally saw above freezing

Snow is an excellent insulator. Somewhere between the inside ceiling and the top of the snow on the roof the temperature goes from room temp to freezing. With enough snow insulating the roof the snow against the roof rises above freezing, melts, and the liquid water trickles down the roof until it runs into cold air. Nasty ice dams are the result. Even well-insulated roofs can have ice dams with enough snow on top. I don't live in Anchorage any longer but always hated having to fight the ice dams on my roof. An ice dam 10" high is bad juju.

Heat tape. Plug it in once a week overnight.

My brother-in-law lives in Northeast Vermont, in sight of the Canadian border. I have seen houses up there in winter with a sheet of ice from the gutters to the ground. Even here in New Jersey we get ice dams on our roofs. The warm air in the soffits melts the snow and it freezes when the sun goes down. After a few freezing and thawing cycles, the ice and water go over the back of the gutter and facia board into the soffit, and from there into the house. Then I see houses with pots and pans in their front bow windows to catch the dripping snow melt. Almost none of these 60 year old houses have ice and water dam material overlapping the facia board to roof deck gap, and almost none of my neighbors bother to do something about the problem.

Here at 1700’ in Central NYS we get both lake effect and nor’easters, up to 200” of snow a year. Metal roofs, snowrakes and heat tape are common ways of preventing ice dams and the subsequent mess. I believe there is also snow melter material similar to rock salt that is specifically for roofs.

I had ice and water shield applied to my complete roof, every square inch of it. Got very tired of dealing with heat trace and leaks...

Exactly.
Warm roof vs cold roof.

Amazing how much time and money some spend every winter on such a baffling problem.

I'm thinking ours isn't working, we've got ice buildup all around our house, insulation might be blocking the lower eaves, gonna have to check that pronto.

Just walked my neighborhood majority of the roofs have bad ice this year, my section of drop-down roof with thaw wires is bad this year. And its snowing again!

When we were building the shop the boiler went out and the mechanical contractor wanted to heat the place to avoid issues with the in floor tubing (as I recall it was a pretty good cold snap). He brought in a big salamander heater, and of course there was no insulation in the lid yet (and no lid for that matter). Overnight it built a 14" thick ice dam the entire width of the overhang, which was not quite 3 feet. I was insulating the walls at the time and so much water came in that the insulation was falling out of the bays.

I spent 10 hours up on a ladder breaking ice over my head with a framing hammer. Make a channel, get the water draining, rinse and repeat.

Ice melt or water softener salt stuffed in a leg of pantyhose and laid over the dam will help a lot to dig a channel. Beware that when a 1 foot by 3 foot chunk of ice finally lets go for a 20 foot drop, you AND your ladder should be out of the way.

Heat trace applied at the eave is worthwhile on a metal roof. They make a specific heat trace for shingle roofs exactly to prevent ice damming. However much prevention it takes is worth having to apply even a little bit of the cure.

Sheesh what a pain!

Good on you for reusing your pantyhose.

It is his favorite mask... but he does not use the legs... hence the excess pantyhose leg sectioms...

I live in neighborhood that went up fast during the pipeline boom of the 70's, so there wasn't a lot of quality effort. I am super thankful that my Dad talked me into blowing in a bunch of extra roof insulation (and maintaining the airflow) right after buying my place. My neighbors' houses have ridiculous icing issues but mine is pretty much ice free.

Installing insulation baffles is considerably cheaper than buying and energizing heat trace, but to each his own.








Durovent UDV2248 Rafter Ventilator Pack of 70, $159.04 link

Keeping a roof system breathing is completely lost on many DIY'ers.
All my life I've had homes in heavy snow county in Alaska and NW Montana and never had a ice dam on one of them.

Properly insulating and ventilating a home in the south is every bit as important. Summer heat build up in attic spaces will cook asphalt shingles from the bottom up shortening the life of them considerably. Moisture trapped in these non-ventilated spaces creates rot, mildew and mold.

Then there's the spray foam guys....

Ha!

You know what I always say.... Waist not, want not.

Ok how to install baffles on existing house no attic from the outside any video links?

That’s catchier than waist not, Ice melt.

Waisted away again! In Victoria's Secretville!

The solution is non-baffling

Build better and repair less , I got 70 r's in the roof , and what ever the outside temp in the rest of the space...

Pretty easy way to add a c-note to your monthly electric bill.

At this point, until the ice melts getting more ventilation (air circulation) in the roof. After the ice melts Art is correct. Ice and water shield from the edge of the roof to AT LEAST 4 feet above the exterior walls. Then figure out how to get more ventilation. I've even put a box fan up in the roof. Helps a lot. Especially after a long cold spell and before it warms up and all that ice built up on the rafters starts to melt.

Your boiler guy had head stuck in arsehole

JeffA is dead on! Proper design (from the start or via retrofit) beats band-aid "solutions" every time.

I totally agree. I built my 3 houses and none every had more than a few 12" ice cycles. I build with Energy Heel trusses. I gives me 8" of insulation room out to the outside of the outside wall. I rarely use the styrofoam air vents anymore. I make the air vents with 1" pink foam . This gives me R5 wiht only 1" of room. I do this about every 3rd truss. Between the trusses that dont have my home made vents , I pack regular insulation about the walls and between the trusses. but push the insulation to the outside of the wall, or at least so I can still see half the top plate of the wall.Then you can use spray foam and foam the top plate of the wall and up to the bottom of the sheathing , under the shingles. Spray the foam up the bottom of the sheathing ( under the shingles) up 4' or so. This eliminates all , or 99% of the ice back damming. Foam is expensive. If its too much , you can take foam sheets and to the same. I put R 60 in my last ceiling with cellulose . I also have 4" of closed cell foam in my walls. The house is so efficient that it would cost me about $1,000 a winter to heat my house at todays rates of Natural gas. It is a 2200 sq. ft. house with bigg windows and 9' ceilings. If I didnt have windows or doors, I dont think it would cost $500 to heat this house. I live in SE Wisconsin in wind swept farm country , so its very windy many days.