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ice damming = roof leak

Posted: Sun Feb 01, 2009 7:28 pm
by butch2
this is sort of a continuation of this thread I started back in dec -I've reasoned it down to having to be ice damming up the water thats trying to move downward but is heading back under the shingle and finding a way down my walls /celiling

https://www.mobilehomerepair.com/phpbb/v ... ing+stains

wife and I figured theres not much we can do about the leak(s) which has produced several 1 to 2 inch stains along the north facing side of the mobile where the wall meets the ceiling .the best advice I got from a contractor was to shovel off the snow which my dad did for me last month ---then wait til spring to hope for stains to dry up enough to then paint over them

however - wife and I have redone all the flooring (mostly laminate in bedrooms /new linolium tiles in hallway/bath/hitchen) in the home except the living room --so we decided to go to home depot and snag some laminate for the living room .

while ripping out the old carpeting I noticed wet spots along the floor directly below the really bad batch of 1-2 inch celiling stains .I'd say in total theres probably around 1 foot worth of these wet spots when you add them all up which probably isnt too bad .The wetness seemed new and not something thats been lingering for a long time -but , I did something out of my comfort level and took off a sheet of paneling to see just how wet it was back there .Much to my pleasant surprise it was actually dry as a desert on the backside of the panelling and all the 2x4's running vertical as well as the one running along the floor and roof support were dry too .I decided to puncture the membrane so I could check out in behind the pink insulation and found that the plywood behind the pink insulation and the backside of the insulation had some frost on it -but nothing too wild and willy .I'm assuming this frost is the water that has leaked down the wall from the ice damming

I'm confused as to what I should do now -wait til things dry up on their own ? File an insurance claim and see if its worthy of gutting ?

third winter here and first time we've had this happen
crazy winter tho -alot of snow and colder than usual

there are no bathroom vent venting into the attic either -its vented through the wall instead

I've started looking at steel roofs but they probably cost more than my mobile is worth

arrgh -advice anyone ?

RE: ice damming = roof leak

Posted: Sun Feb 01, 2009 7:33 pm
by butch2
p.s -might look into this next winter but I'm not sure it would have the moxy to handle a northern canada ice buildup

http://www.heatersplus.com/easyheat.htm

Posted: Mon Feb 02, 2009 9:48 am
by flcruising
The culprit to ice daming is too much heat 'leaking' to the attic. If you can insulate and seal up your attic well, the ice daming will go away.

http://www.umass.edu/bmatwt/publication ... _dams.html

http://www.energystar.gov/index.cfm?c=h ... nt_icedams

RE: ice damming = roof leak

Posted: Mon Feb 02, 2009 11:47 am
by Greg S
Actually although lack of insulation is a contributing factor the real culprit is probably lack of ventilation above the insulation. Ventilation at the eves and peek (if there is one) prevents the heat escaping from the interior from heating the underside of the roof which causes the snow/ice to melt on the roof leading to the ice dam. You need to add ventilation if possible.

Posted: Mon Feb 02, 2009 1:12 pm
by flcruising
Yes, forgot that part. :)

The articles explain completely.

Posted: Mon Feb 02, 2009 10:28 pm
by Jim from Canada
To solve the problem, you have to stop the leak. You are saying you have shingles, so I am going to assume you have a pitched roof. Likely a low slope, which is what I have. I re roofed my place. You don't have to go as drastic as I did but here is what you want to do.
Strip the shingles and repair any weak spots in the sheathing. The sheathing should be minimum 5/8" T&G OSB if your trusses are 24" OC.
Metal edging on eaves.
Cover the sheathing entirely with Ice/Water sheild (get Grace brand if you can, it is twice the price , but worth it).
Metal edging on the gable ends
Shingle and flashing.

Look at my photo album to see the job I had done. In addition to the above, I upgraded the sheathing to 5/8" Plywood, I added a 2x4, on edge to each truss to make room for more insulation in the catedral ceilings. I also upgraded to a shingle more suited to a low slope.
It rained the morning of the shingling. The roof had only the Grace on the sheathing and I had no leaks. It never will.
I plan on opening up the inside as there is no vapour barrier in the house. I will install styrofoam baffles from the eaves to the ridge vent (having a cold space between the insulation and roof is very important, unless using spray foam....use "Walltite" if you sprayfoam). I am then going to install 10" of Roxul insulation (R 36) by using both a 4" and a 6" batt. 6 mil vapour barrier is next, then finished walls.
Hope this helps

Jim

Posted: Mon Feb 02, 2009 10:34 pm
by Jim from Canada
P.S.
While I was at it I had the eaves extended to about a 1 foot overhang. My Soffits sit higher now but I added a freize board above my siding to make up the difference. Had the freize board covered in aluminum and aluminum soffit installed. I have about $7000 put into it. I would have saved about 1/2 that if I was able to (physically, buggered my knee up) do the job myself. I have the fascia yet to do.

Jim

RE: ice damming = roof leak

Posted: Tue Feb 03, 2009 1:28 pm
by butch2
thanks for the advice gentlemen

jim , my fellow canuck -the shingles we're done in 2004 and they are in very good shape after I inspected the roof before buying the place in 06 .former owner kept all receipts and the job was done by one of the better contractors in town so cant imagine he'd forget to use the proper sheathing etc.....but I guess you never know .

I still have the sheet of panelling off the wall and things seem to be drying up .I'm gonna sit tight and see what happens this coming weekend as its supposed to warm to +7 celcius on saturday --compare that to -35 this morning .

Posted: Tue Feb 03, 2009 3:00 pm
by Jim from Canada
Well, what I described is well above code. 24" OC trusses can have 1/2" OSB sheathing with H clips, but have you ever walked on one built that way? Not good. Code also only requires tar paper for the bottom 3' under the shingles. Again, a recipie for a leak. Keep your eyes peeled and see what you come up with, I am looking forward to warmer weather too.

Jim