We presently have substantial ice dams on a roof that was done about a
year and a half ago (complete rip-off of old shingles down to plywood,
installed 30-year GAF architectural shingles). Our contractor, a
really reputable firm in my area, installed the ice & water shield
under the shingles along the edges of the roof. Long story short, we
are getting water intrusion into the house now from melting ice/
snow. Isn't the ice & water shield supposed to be a foolproof way
of protecting against this, or is it only a half-measure? Also,
what are my alternatives right now? Just let it melt off? Or should
I get it shoveled, and if I do so, will this damage my semi-new roof?
Obviously the Ice & Water Shield is not foolproof. As in everything
else in roofing, it's all in the details. If the membrane does not
wrap over the edge of the roof and get adhered to the sub-fascia or
fascia, or even inside the gutter, then it's not a big stretch for an
ice dam to back up water under the membrane.
I am not saying that is definitely what is happening on your roof, but
it is a possibility. It depends where exactly the water is coming
in. It can travel a fair bit before showing up, depending on the roof
construction, vapor barriers and such.
Shoveling would damage the roof if the shovel was strong enough to
break up an ice dam and it was scraped against or chopped into the
shingles. It depends how much is up there what's the best way to
Ice dams are cause by to warm an attic which can be usualy be traced
to air infiltration or lack of enough insulation. You need to stop the
ice from building up or will be getting bigger issues like rot. Get an
insulation guy out, its not a roof issue.
Ice and water shield may not go high enough. It's best to cover the
entire roof with it.
Shovel your roof asap and keep it cleaned off for now.
Get your attic insulated to cut down on bottom melt. You must have a
great heat loss in your home.
It all depends on the weather around your home. Many people here have ice
dams and icicles. The outside air is way below freezing. The sun shines
on the roof and begins to melt the ice. Then it is night time and what
water there is, refreezes. Then it starts up all over again day after day.
The result is an ice dam. Using a roof rake as much as possible is what we
do. If it gets any worse, we may have to call in roofers to go up there
and shovel off more than we can reach from the ground. We're older people
so we can't go up to the roof.
Unless you're related to them, and end up having to tote their bed pans
while they recover from the hip replacement, if they recover. I'm the
wrong side of 50, and while I do still (very carefully) go up on my
single-story roof, I don't get nearly as close to the edge as I used to.
My inner ears started telling me NO! about five years ago. I don't
bounce worth a damn any more.
And I raked the bottom five feet of the lee/shady side of my roof
yesterday, from the ground. No leaks, but my metal-wrapped gutter boards
that always stay wet are already rotted, and I'm afraid that if I let
the iceberg get too big, a gust of wind will tear the whole mess off the
house. Of course, that WOULD force me to fix it all correctly....
Up in the Great-White-North, roofs which ice damming is a problem, the old
school solution is to start the roof with about 3 or 4 feet of sheet metal.
Sheet metal is laid on the eaves, it covers and seals the cold part and the
warm part of the eaves. The first course of shingles are then laid, 3 or 4
feet up from the edge of the roof/eaves. If large sheets of ice fall off
the metal, causing a hazard below, a rail system is usually installed on
the sheet metal. The rail system is about 6" from the edge and is about 4"
tall. I think in the old days they would lead solder the over-lapping joints
of the sheet metal and then paint the metal to match the colour of the
If a younger person falls most of the time it's injuries. For an older
person, it's probably a death sentence. My 92 year old neighbor decided to
ride a bicycle. He fell and injured his ankle. Then it was complications
and he was in a nursing home for a year where he kept going downhill and
Nothing wrong with the ice dam. You don't have proper soffit to peak
ventilation. Attic insulation could probably be improved, too. When
the weather permits, get your roofer back and have the ridge vents and
soffit vents re-engineered. Attics need to be as close to outside
ambient temperatures as possible.
Agree with everything everyone else says. Make a plan to look at
insulation and attic venting before next year. In the meantime, you
might want to try some of those hockey pucks they sell at the Borg
(made of salt or some such material that you hurl up into the trouble
areas - if you have a decent arm you might be able to alleviate the
issue and stop the infiltration). Some people round here use a long
sock filled with ice melter, which they place on top of the dam (or if
you get to it before it forms, the gutter). That might help also, but
may involve a ladder...
Was this a problem before or just after the new roof? If the latter,
suggests they changed something, probably the ridge vent. Not all
ridge vents are very effective.
Hmmm, apparently the hockey pucks are a waste of time. My work buddy
tried them on his house over the weekend - apparently no difference
whatsoever, despite the ambient temperature climbing up into the low
Two ways to remove them that I know work.
1. Get the roof heating cables. Get a bunch of pine 1 by 4s. Space
the 1x4s about 2-3 feet apart. Run the heat cables in from one to the
in a series of loops about 2 feet apart; fasten with romex or coax
clips. Put the whole mess up on your roof with one row of 1x4s up on
the roof above the ice dam, the other just over the edge so it pulls
the loops of heating cable down against the ice dam. Plug it in and
give it a few days to melt slots into the ice dam which will allow the
trapped water to flow out. Effective, but slow. Works best if you do
it a couple days before the roof starts to leak. :-)
2. Hire a professional that will use a steam generator feeding a
wand. They will use the wand to cut the ice dam into chunks which
can be tossed off the roof. If done properly, it won't damage your
roof or gutters.
As far as the cause of ice dams, the basic mechanism is that the low
part of your roof is coldest, especially if you have overhangs. The
high part of the roof is warmest, because 1. any heat in the attic
will rise to the highest part, and 2, often that where the most solar
heating happens. When the high part of the roof is above freezing,
the snow there will start to melt. The water will run down, under the
snow, until it gets to the cold part of the roof where the temp is
below freezing. It freezes there and starts to build the dam. This
repeats each day/night cycle.
Poor insulation, poor ventilation, or heat leaks into the attic
increase the likelihood of this happening, but it can happen with a
well insulated attic with no air leaks and proper ventilation when
the outside temp is only a little below freezing and there is solar
gain to the high part of the roof.
One way to minimize the process, before the dams form, is to rake the
snow off the roof, but you have to rake the top. Many folks try to
stop it by raking just along the bottom, but that often makes it worse
because the bottom get colder faster without the insulating snow, and
you haven't removed the source of the water, which is the melting snow
Once it starts leaking, option 2 is your best bet, if you can find
someone in your area that has the proper equipment and knows how to
use it. Do not hire anyone that plans to chip the snow and ice off;
this will damage your roof and gutters for sure.
re: "2. Hire a professional that will use a steam generator feeding a
I had ice dams and leakage into the house real bad one year. (I've
since solved the problems with Ice Melt cables)
My friend owned a carpet cleaning company and had a truck with the
water heater and hoses, etc.
Business was slow during the winter and he wanted to make some extra
cash, so we agreed that I would take pictures and videos in exchange
for him clearing the ice dams with hot water and high pressure nozzles
on the ends of the hoses from his truck. He was going to make a
commercial and print brochures and hire a few guys to help him.
I'll say 2 things about the experience:
1 - It worked. He cut the jams into 1' - 2' sections and then undercut
them to get them to fall off the roof. The leaks stopped.
2 - He never did it again. It took so long that there was no way he
could charge enough to make it worth his time. By the time we were
done, everything - including us - was covered in ice. Walking was
extremely hazardous, climbing ladders was next to impossible and our
hands were numb.
He went on to become a home inspector and never looked back.
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