# Ice Dam -Gutted and now unsure how to fix.



## 10Char2Much (Nov 4, 2018)

They made this an add-on Porch I guess 30yrs ago -We moved in 5yrs ago. We get destructive Ice dams. 2yrs ago New Roof with Ice-Water underneath.. Guy also said he can help with fixing the affected porch..Well we got more water inside, sheet rock was soggy and water running down from the ceiling where it meets the door. The beams they used 30yrs ago are 2x4 and for the most part are 24" on center...The Guy used R19 with new 2x4s 16" on center. I'm not sure the best way to fix. I know I need more insulation I live in Massachusetts, I know the chart to show me how much R value I need, but not sure how to fix the 2x4 problem. I would guess remove all the new 2x4's and add on top of the older ones to achieve 7"


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## Nealtw (Jun 22, 2017)

The white woold in the wall is the original beam, expose that right a cross, cut the new 2x4 shorter and drop the into hanger at the white beam. 
Venting is needed at the low end soffit. And at the top end, tricky.


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## Bud9051 (Nov 11, 2015)

Do those rafters hang over the wall giving you a soffit area?
Difficult to fix with just 2x4's up there. Adding another 2xr may give you 7" but you need 1" to 2" for a vent channel. You also need a high vent to give the warm air a place to exit.

Can you post a picture of the outside?

Bud


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## 10Char2Much (Nov 4, 2018)

Thats the outside..Thank uou all gor quick responses -Bob


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## 10Char2Much (Nov 4, 2018)

One more outside


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## Nealtw (Jun 22, 2017)

10Char2Much said:


> One more outside


 So how does this roof tie into the house or other roof?


It looks like there is some blocking between the rafters we would need some open space between each rafter pair.


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## Yodaman (Mar 9, 2015)

R19 is light for Mass, should probably be R40 min. for a ceiling. Going to need baffles to keep a airway open. Since you have 2x4 ceiling rafters, I would likely put in faced R13 first same direction as rafters. Then run unfaced R19 perpendicular to it. 

As others suggested, you need a high vent to exhaust. And last, was ice and water shield put down under the shingles?


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## 10Char2Much (Nov 4, 2018)

Here is where the side wall meets the roof.


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## 10Char2Much (Nov 4, 2018)

Yes, Ice Water is under the new roof.


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## Yodaman (Mar 9, 2015)

Lots of pics, but still don't see a exhaust anywhere. Stand out in the yard 20-30 feet and take a pic of the roof.
The exhaust vent is critical if you want to have a chance of success.


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## joecaption (Nov 30, 2011)

Most common causes for ice dams and leaks I've seen on a shed style roof like that are lack of enough pitch, not enough insulation and no venting.
When that new roof was installed I wonder if they followed the manf. suggestions on how to shingle a shallow pitched roof?
Should have been doubled up 30 LB. felt and less exposure on the shingles in most cases. 
Looks like they used vented soffits, but are they open to the attic on the back side so air can get in?
In your area I'd suggest using 2 gable vents, roof vents would just get covered in snow.
I agree R-40 is about the min. amount of insulation needed and I'd also add a vapor barrier before the sheetrock.


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## Bud9051 (Nov 11, 2015)

Been following but don't see a vented solution that provides the r-value and air flow. This might be a good place to use spray foam directly under that roof deck. It would need to be thick which is expensive but it is closer to "one and done" than anything else. Cold temps are not the friend of spray foam so very soon or next year.

Note, we have not discussed any snow melt coming from the main roof and it can be contributing to the issue. Not sure if there is any soffit venting left for that.

just wanted to introduce the spray foam (may have been mentioned) for consideration.

Bud


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## 10Char2Much (Nov 4, 2018)

There is no exhaust vent on the sides or roof -The black pvc coming out of main roof was placed there by plumber when they correctly reinstalled upstairs drain issues we kept having.


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## Yodaman (Mar 9, 2015)

It looks like you may have a ridge vent installed in the main roof. Can't tell from here.
If so, you can cut some openings in the old roof deck which is now covered by the porch roof trusses. (ref pics from post 8) This should have been done during the original porch construction.


Rigid foam 2" under the ceiling trusses but about the drywall will help with air sealing and also add R10 of insulation.


Also, is this a cold room? Non-heated porch?


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## Dave Sal (Dec 20, 2012)

Looks like you have no venting at all. No roof vents, and I doubt that there are any soffit vents under your eaves. The goal is to have the temperature in the attic space as close to the outside air temps as possible. That way, snow won't melt and then refreeze, backing up under your shingles causing the ice dams. 

Add lots of soffit vents. As an example, I have about 36 or so on my house, half on the upper level and half on the lower level, along with two static vents on each roof. I also have a powered attic fan on the upper level. A remote temperature probe in the upper attic shows that the attic temps stay about 5 degrees above the outside air temps most of the time.


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## NotYerUncleBob2 (Dec 29, 2017)

It's a fundamental design flaw. A low near zero pitch with a higher pitch roof above it will always eventually have problems like this. 
Here's what's happening:
-Snow falls covering both roofs.
-Snow begins to melt on both roofs, but it all runs to the low pitch porch roof where it starts to pool under the snow. 
If it isn't getting under the shingles at this point, it soon will.
-Sun goes down and it freezes solid.
-Sun comes up and the upper roof snow begins to melt again and run down to the lower roof where it's already frozen and now you for sure will have water under the shingles and finding its way into the house. 
So, what are the solutions?
Option 1. Build a new gable roof and valley over the porch to give enough pitch that all water just goes on its merry way to the gutters. 
Option 2. Create a freeze proof roof so ice dams can't form. Unfortunately this is nearly impossible because you just don't have enough space and eventually Mother Nature will create the conditions to overcome your plan. Always. Nature has a 100% track record over enough time.
Option 3. Just heat the outside of that low pitched roof to melt the snow so you don't get ice dams.


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## Nealtw (Jun 22, 2017)

High end venting can be done by cutting holes in the sheeting on the old roof 
As long as the house roof has proper venting but this should be open to help the venting of the house roof. The bottom 2 boards should have been removed when this addition was built but of coarse it was just built as a roof over a deck so they did not have the need at the time,


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## Yodaman (Mar 9, 2015)

Doesn't help you now, but maybe someone else. When I re-shingle these shed roofs that merge into the main structure, I run ice and water up the entire porch. Starting at the bottom with 100% coverage all the way up past the transition a couple feet. 

It doesn't solve the insulation and venting issues but does give you a fighting chance.


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## Nealtw (Jun 22, 2017)

Yodaman said:


> Doesn't help you now, but maybe someone else. When I re-shingle these shed roofs that merge into the main structure, I run ice and water up the entire porch. Starting at the bottom with 100% coverage all the way up past the transition a couple feet.
> 
> It doesn't solve the insulation and venting issues but does give you a fighting chance.


 That would be helpful, ice dams would be problem above both the shed and the house walls. But now he needs venting to move moisture along and out.


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