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Ice Dam problems and repairs (part 1)

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In 2005, we had the roof re-shingled. The back of the house has a full dormer on my Cape Style house. So it has a 3/12 slope on top of the full dormer. I asked the roofer to put down ice and water shield over the entire back roof and shingle over. 2011 weather created the perfect conditions for ice dam. So, we had water backing into the house from ice dam. It took me a while to figure out how water got in as I have mention the back of the house has ice and water shield over the entire back roof.



 



After some good research on how ice dams are formed and what creates them, I learned a few things about proper insulation and ventilation. I realize that the roofer did not install the first layer of ice and water shield properly. I realized that even though in 2009 I had an insulating company top off the attic with blown in cellulose that was not good enough to prevent ice dam.



 



The roofer did not remove the gutters to overlap the ice and water shield over the fascia board. When the Ice Dam was formed on the gutter, water backed up and flow under the ice and water shield and worked its way in. My house was not properly insulated and ventilated. There was heat lost above the bathroom fan. This was the heat source that started the ice dam.



 



Because lack of proper insulation and ventilation above the bathroom exhaust fan, the heat lost melts the snow, water runs down toward the frozen gutter but it is back up from the frozen solid gutter. The water works is way under the ice and water shield and in the house. 1-27-2011



 



snow melt above bath vent location2.jpg



 



 



Water stain on bathroom ceiling caused by the ice dam.



bath fan n water stain.jpg



 



 



Removed bathroom ceiling drywall. Moved exhaust fan because there is not enough space above the fan for proper insulation and ventilation.  Insulated low ceiling area with 4 inch thick rigid foam insulation because the joists are 2”x6”. Leave about 1” air space between rigid insulation and roof sheathing for intake air. Spray foam any gaps around rigid foam to seal leaks. 4-21-2011



bath fan rigid insl installed 1st 3ft from ext wall.JPG



 



bath fan moved1.JPG



 



 



The house does not have eave and soffit vents for intake air. I removed part of the chimney so it will be below the roof line to make room for the new eave. The back chimney is not used so it is capped now. Contractor installed blocking for soffit vent installation.  4-22-2011



back blocking over bath2.jpg



 



 



 



back blocking for soffit vents2.jpg



 



 



Contractor removed first 3 course of shingle from the roof. Installed new Grace Ice and water shield and make sure it overlap the fascia board. If there is ice dam build up on the gutter, water cannot backup under the ice and water shield. 4-22-2011



 



back soffit vent ice n water shield.JPG



 



 



With proper soffit intake air and ridge vent (exhaust air), the gable vents are covered up. 5-4-2011



 



right side view of house.JPG



 



 



 



No snow melting with proper insulation and ventilation over the bathroom area. If there is excessive heat lost, you will see the shingles on this picture and not a white roof. 1-17-2012 Need more snow for update.



back of the house 1_17_2012_2.jpg



 


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in all the years of construction, I have never wrapped ice and rain onto the fascia, ever, if your soffits were vented correctly,like they are now, you wouldn't have had ice back up, bathroom room vans are notorious for being vented wrong, all the work you had done looks good,

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Looks good . Nice job.



 



Ice and water shield is installed correct.  It is suppose to overlap fascia and gutter goes on top of ice and water shied.  In fact, when you re roof you are suppose to take gutters off,ice and water shield installed properly and reinstall gutters. This is from roofing manufacturers such as GAF and others. If you think about it how else would it work. Even if your soffits and ridge are vented properly there could be certain days it could back up.


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Looks good . Nice job.

 

Ice and water shield is installed correct.  It is suppose to overlap fascia and gutter goes on top of ice and water shied.  In fact, when you re roof you are suppose to take gutters off,ice and water shield installed properly and reinstall gutters. This is from roofing manufacturers such as GAF and others. If you think about it how else would it work. Even if your soffits and ridge are vented properly there could be certain days it could back up.

 

it could, but if it's ventilated right and insulated right you should have no problems, oh, and I won't use cobra vent anymore, GAF snow country vent for me these days, even the GAF rep I talked to says the cobra vent is junk,

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AS in the picture above the gutter goes on top of the ice and water shield and the new roof would hang into gutter. This way the ice and water if it backs up is always on the outside. If you are going to do aluminum fascia under the gutter you have to tuck it under ice and water shield.


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That looks great, I extend my I&W over a 1/2'' on my rakes and eaves. Thats how Certainteed likes it, so thats how I do it. Im qualified to give a better warranty than other roofers who are not certified by certainteed, but my work has to be done to spec. I agree though that it probably doesnt matter as long as you have a properly ventilated house

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I use 3/4" so when you go up the roof with your edge shingle plus your shingles it all lines up.

 

Well, I use drip edge up the rakes too so it all gets covered anyway, but if you are not using drip up the rakes, the specs call for a 3/4 overhang of I&W, so good job

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Well, I use drip edge up the rakes too so it all gets covered anyway, but if you are not using drip up the rakes, the specs call for a 3/4 overhang of I&W, so good job

 

drip edge all the way around for me, 1/2 inch overhang on the first course, 3/8 overhang up the rakes. Also I use the swiftstart as my first course so it will self seal to the starter course of shingles,

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drip edge all the way around for me, 1/2 inch overhang on the first course, 3/8 overhang up the rakes. Also I use the swiftstart as my first course so it will self seal to the starter course of shingles,

 

also, I snap my lines from side to side and top to bottom, if I have to adjust to keep the overhang even all the way across I do, I've been very fortunate to work with alot of good carpenters who have taught me on how to do things correct,

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