I live in a northern climate. Had major ice dams last year. A new roof was installed with ice and water shield, gutters and gutter covers, oversized downspouts and heat cable that is zig-zagged on the roof, in the gutters and down the downspouts where I have them plugged into outdoor electric stakes with switches that run to outdoor outlets. Is there a rule of thumb for when to turn the power on? Once it starts snowing can I turn it on and leave it? Do I need to wait until I have some accumuilation?
Thanks for your help.
Robin

 

We've had plenty of experience with ice damming before we put up the roof wires. To save on elect. expense I don't put the wires on early and wait until there is a a couple of inches but if it is a fast storm with heavy snow then I do put them on with the first fall of snow. After the storm and when the wires have melted a path through the snow then I just put them on at night to prevent the snow melt from refreezing.

 

Is there any danger in keeping the cables on all the time?

 

You can install a heating cable controller so they turn on only when neccessary.

Click for larger image

 

You probably already considered this, but the real cause of ice dams is excess heat in your attic. Air seal, insulate, and ventilation and no more ice. I know a lot of people use the heat wires, but I like to thing of them as back-up. Plus, reducing the heat loss into your attic, will reduce your heating costs.
Bud

 

Sorry don't mean to hijack this thread but my post HERE is about ice daming.
Maybe something from my question can help you or help with answers from your post.

I did renovate my attic into a living space and I paid good money to have "Corbond" foam insulation sprayed on the ceilings. So heat lose isn't an issue. I was even having this issue before my renovation. When my attic was cold as the out side temp (like it should be).

So if I were to get these Heat Cables what is the cost to run them. It is a rental property and they pay there own utilities. Also power would have to be run from outside since the attic is all buttoned up with drywall.


Thanks in advance. And sorry again for the hijacked thread. :Peeping On U2:

 

Even a well insulated and ventilated roof can have ice dam problems.
A lot depends on the design and orientation of the roof.
And weather conditions.



Ice Dam Leaks

Cost would depend on how long you needed to keep the heat cables on to melt the ice/snow.

 

bud is on the money ,you need proper insulation to keep the heat where it belongs,if you don`t have enough space for fiberglass to raise the r-value,look into closed cell foam insulation with r-values at 6.5-7 per inch---you can check it out at www.soythane.com

 

I'm in Utah and my cables have been on straight for 5 days because of daytime highs under 30. The "pathways" are melted, so is it o.k. for me to turn them off during the daytime. Nothing dripping down the downspouts...........

 

I'm in Utah and my cables have been on straight for 5 days because of daytime highs under 30. The "pathways" are melted, so is it o.k. for me to turn them off during the daytime AND nightime if absolutely nothing is melting??? Nothing dripping down the downspouts...........

 

the cables should be off when not melting ice,you should also monitor heat cables ,to check if they are old,frayed or in need of replacement,nothing like a frayed electrical wire in a water melting situation---you should look into proper insulation.ventilation,and waterproofing so you don`t need the cables---no heat loss =no ice

 

thx r.g. cables are brand new; R-57 new insulation. ( am concerned about getting fan put up there in attic when summer hits tho, because insulation is maybe too much for heat.) and I turned cables OFF while not melting. but alas more snow this a.m. so back on until pathway is melted again.

 

At what temperatures do you suggest turning them off and what temperature do you turn them back on. I have switches ,no thermostats.

 

Welcome to the forums.
An older thread but a topic that is always current.

There really is no set temperatures but it's not very effective to have them on much above 35-40 degrees. I have several here on very shallow pitched roofs. Our temps don't usually stay that cold for too long so I only run them just when the snow ends for a couple of hours. Maybe the next day for an hour or or two to make sure the path is cleared. Sometimes if it's real cold and there is a lot of ice.... I'll leave them on overnight.

I know people that "turn them on for the winter" Definitely not energy efficient.



Pete

 

I have roof cables and I get huge icicles hanging off. Is there any way to alleviate this? Are the cables installed correctly? They appear to be installed per manufacturer's specs. I have always turned them on during or after the snow. Should i be turning them on just before the snow is to begin?

 

Forming ice usually has a magic temperature where it is warm enough for the melt under the snow to run down to the edge where it is cold enough for that to freeze. Where I live the magic temp is in the lower twenties. It also varies with the amount of snow which insulates the shingles and allows the heat from the house to melt the bottom layer.

But be careful. Eliminating the ice dam at the bottom still allows them to form up higher. Plus there is the weight of the snow that may ultimately need to be removed.

I don't use the heat wires so can't give more specifics.

Bud

 

There is a thread on here somewhere regarding ice dams that gets referenced every year around this time.

Had some pretty good info if I remember correctly.

I'll see if I can find it.

Hmm, found it but the article that was very helpful was generated by the Canadian Mortgage and Housing Corporation and they've removed it as 'expired content'. Rather unfortunate.