Ice Dams and Roof Snow

Wednesday, September 20, 2017

There is a good deal of confusion surrounding ice dams and problems caused by snow buildup on roofs.  Here is what you need to know:

Q: What causes ice dams?

A: Accumulations of more than about 6″ of snow can — depending on certain factors — lead to ice clogging your gutters as melting snow runs into the gutter and freezes.  Eventually the gutter can fill with ice and snow and prevent additional water from draining off the roof.  Instead, it collects behind the ice buildup (the dam) and begins to form a pool.  The snow along the bottom edge of the roof also acts like a sponge absorbing and holding excess water that freezes on top of the ice in the gutter forming a rock-hard barrier.  The problem here is that roof shingles are only effective when water runs down, not up.  The pooling water leaks under the shingles and through the nail holes and gaps between roofing boards or panels.  If you see icicles on your gutters, you are prone to ice dams.  NOTE: Unheated garages DO NOT present an ice dam problem, so don’t worry about them.

Q: Does removing the gutters help?

A: Yes, but it can present other problems like basement leaks and damage to landscaping under the edge of the roof.

Q: What can I do?

A: There are a few different things you can do to prevent ruined walls and ceilings from ice dams:

1. ) If you already have a ridge of ice along the gutter you can apply a generous portion of the same ice melting product you would use on your steps and walkways.  The same product also comes in bigger tablets specifically made for melting drainage channels in ice dams.  One old trick is to put about a pound of rock salt in an old sock or nylon, tie it off and lay it on top of the ice dam so it melts through the dam and provides an outlet for the water.  Ideally, you’d need one of these every 8′ or so.
2. )  Be sure your gutters are cleaned and downspouts unclogged so that water drains correctly.
3. )  If you are getting a new roof, be sure that the roofer installs more than the code-required minimum of a single strip of ice and water barrier along the eaves prior to installing the shingles.  By code this rubbery membrane must extend 24″ over the portion of the roof covering the living space (even if it’s an unused attic).  On low-slope or ranch style homes it makes sense to cover the entire roof with such a membrane rather than using other underlayments such as roofing felt or synthetic equivalents.  The ice and water barrier is soft and gooey when heated by the sun.  It seals around the nails so that water has a much harder time finding a way in.
4. ) The best thing to do is keep excess snow from piling up in the first place.  Buy a roof rake or hire someone to rake your roof for you.  BUT BE SURE TO DO IT RIGHT!  It is important to understand how to correctly rake the snow from the roof so you don’t inadvertently cause more damage!  Snow is like a sponge, it will absorb and hold water.  This means that wherever there is line between several inches of snow and a cleared area of your roof  below that line, a new ridge of ice will form if that wet snow freezes further.  Because your roof probably has just a 3′ strip of ice and water barrier (of which about 1′ is wasted covering the overhang), you should only rake the first 12″ of snow at the edge.  If you reach up too far and rake all the snow you can reach, A NEW ICE DAM WILL FORM BEYOND THE LAYER OF PROTECTION afforded by the ice and water barrier.  So don’t go nuts; stand on the ground and only remove 6-12″ of snow from the edge over the gutter at a time.  Repeat as needed.   If you go too far, ALL the snow would have to be removed and you really don’t want to go up on your roof in winter.   However, if this does become necessary, call someone for help.
5. ) Be sure you have enough insulation in the attic.  Heat escaping from below is what causes the snow to melt on the roof in the first place.  Yes, there is some solar heating, but the blanket of reflective white snow keeps most of the solar radiation away.  It’s heat loss that is the real culprit.  In Massachusetts there is a great program that analyzes energy efficiency in a home and subsidizes insulation.  See www.masssave.com for details. (Please note we claim no ownership of the image below, all rights belong to the University of Minnesota Exten. Service)

 

 

 

 

 

 

 

 

 

 

You can also install ice-melting roofing coils along the bottom edge of the roof.  There are very effective, but a bit of a waste of money unless you buy really good ones and install them yourself, assuming you are both handy and a decent electrician.  Otherwise you will need to hire an installer and an electrician.  If you buy the cheap coils from Lowe’s or Home Depot you will be lucky if you get a year or two out of them.  They are prone to breaking and the flimsy wires are easily damaged by falling ice, tree branches and roof rakes.  However, if you are installing a new roof, you might want to consider a product like HotEdge (www.hotedge.com) that is a drip-edge (thin metal strip that’s part of every typical shingled roof) with a metal coil inside so that the coil is not exposed to damage.  It’s not cheap, but does seem like a good investment.If you do suffer leakage from an ice dam and it stains your ceilings without causing any bubbling or cracking, you may be able to remove the stain with a simple trick.  Mix 1 part bleach to 3 parts water in a spray bottle and spray it liberally on the stains.  You may need to do this a few times, but if your ceiling has relatively few coats of paint or has an unsealed popcorn texture finish, you will be amazed at how well this can work.  We saved a number of homeowners thousands of dollars by telling them this little trick.  Just be careful not to let the bleach solution get on your clothes, carpeting or furniture! What about mold?  Well, if the water leaks down into your walls in winter, mold almost never grows. It’s simply too cold in the wall and typically dries out before a problem occurs.  The same is true in unfinished attics.  If you have an old house with plaster walls it’s REALLY unlikely mold will gain a foothold. So don’t panic!

In addition, we are an authorized dealer and installer for a gutter guard and valley heat panel that comes heated and can be installed in order to help your home avoid getting those costly ice dams! All Weather Armour offers two versions of their heat panels that can stop the ice from forming! (http://www.allweatherarmour.com/) They come in different styles the ones that insert into your gutters, and ones that go over the top of your gutters, and the panels that follow the valleys on your roof!

Wondering what All Weather Armour’s products look like?