Ice damming -- cold roof, sun melt

1/24/2011 at 11:03:53 PM

I guess a few questions a person needs to know is how old is the house, and is it properly insulated.

your attic space should be the same temperature as the outside temperature. the way the snow is melting on your roof is cause of heat loss along your wall line where it is closest to your roof. it melts the snow and refreezes right away causing ice damming. you need to make sure you have proper air flow into your attic, you need to have perforated soffits installed, and proper vents that allow that air to flow up on the underside of your roof and keeps the attic space the same temp, it also helps keep your shingles from drying out from the underside in summer also. Or over baking them if they are asphalt shingles. Attached is a picture of what should be proper ventilation

Hope this helps you

1/24/2011 at 11:20:53 PM

ryan is correct. it is either the insulation issue or ventilation. the first step for homeowner is to look into attic see if you see sunlight that would mean that nothing is blocking your soffits. second count how many roof vents you have at top of roof. as per o.b.c should be 1 vent per 300 s.f. of roof. check wall between the garage and house to see where possible leaks are. also check if have proper insulation in attic.

another quick fix is to get those heating cables installed on roof, they heat up so that it continually melts snow and ice. good luck

1/25/2011 at 4:13:56 AM

Both Ryan and Nick are right in regards to proper air flow and insulation, But they didn't mention that it doesn't hurt to put extra bafolds in the roof to get more air circulation, and you might want to check where they installed the down spouts to your roof or add another one so that the water runs away from the garage. Soffits are only so big it easily over flow as well.

1/25/2011 at 8:51:44 AM

Ryan,Nick and Lindon are correct but you could go an extra step and re roof ( which could be drastic) and install water and ice shield around the perimeter of the garage roof. It will prevent water intrusion, attic vents in the gable or what have you and more insulation to keep the temperature true from peak to eave.

1/25/2011 at 11:37:54 AM

Rob etc are not right in that they are not answering the question -- I specifically said the area of ice damming is the unheated garage roof.

There is no attic, no insulation, no sun peaking through.

The sun is shining on snow laying on cold asphalt tiles; the snow melts into the gutter which freezes solid very quickly and the continuing melt overflows onto the walkway into the house.

The

1/25/2011 at 11:38:52 AM

correction -- cold asphalt *shingles*

1/25/2011 at 12:32:15 PM

Unfortunately, there is no cure for the ice damming on the roof caused by the sun. You will always have the freeze/thaw activity, but you can eliminate the slipping hazard on your entrance. Install gutters with heat tracing cables to move the water away from the entry. I recommend installing two rows of heat tracing cable through the entire length of gutter and down through the downspout. This will keep the water flowing and eliminate the majority of your slipping hazzard. I do not recommend installing these cables on top of your shingles, they will reduce the life of your asphalt shingles.

1/25/2011 at 12:34:58 PM

Perhaps extending the roof or moving the walkway further from the garage in the spring.

Removing the eaves trough might be another avenue .

I do apologize, I was reading from the answers and got caught up.

1/25/2011 at 1:39:02 PM

Hi M- unfortunalty, you are going to get ice dams under certain climatic conditions no matter what. There is no 'fix' for it, but you can help it a little. The heated cables are your best bet- I had major ice damming last year, slippery walk- same as you. This fall I installed the heated cable- the ice dams are back, but not near as bad as last year. Its certain weather conditions wherein the eavestrough fills with a fair amount of snow. In between snowfalls there may be a small melting period- the water heads for the eves but ends up freezing along the way resulting in the dam. My advice- grin & bear it, salt & watch your step, and start counting the days til sprin.

1/25/2011 at 4:54:42 PM

I agree with the heated cable, but under no circumstance should you fasten these cables to the roof, this will only cause more damage to your roof and deck from build ups and water flow interuptions. Here is my solution...

Check to make sure eavestrough is on the right slant/slope towards the downspout/exit then simply run the heated cables through the eavestrough and downspout repeatedly (if you have the water dismisal at the base make sure to have the cable runs out the end, and for city dismisal then make sure it runs at least to 2-3 feet into the ground ). This will keep bottom from freezing causing damge in the downspout (bursting) and backing up of ice and water that has nowhere to exit but over the side onto walkways and foundations causing a safety hazard and another ice daming / ice jacking problem in the foundation which is obviously very costly.

1/25/2011 at 5:23:40 PM

Thanks, all. Very helpful replies.

1/26/2011 at 1:35:03 AM

One solution we have used for this is a heat trace wire in the gutter. This stops the water freezing in the gutter.

Another option is a gutter cover which keeps snow from accumualting in the gutter - often the wet snow freezes and accellerates the ice damn and overflow onto the sidewalk.

The other possible solution is more slope along the length of the gutter .....no standing water=no water to freeze

Hope this helps.

Robert

2/5/2011 at 4:03:06 PM

Hi M I don't feel Robert from Vancouver is correct at saying put a cap over troughs ,You didn't pay to have them put on not to be used ,I think a heating cable is your only constelation . thanx bill