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Ice Dam HELP

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Old 12-25-2008, 11:11 PM   #21
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Re: Ice Dam HELP

Soffit ventalation allows cooler air to travel under the sheathing from the soffit through the attic to the ridge vent, this keeps the roof itself cooler and less ice/snow melt. The ice jamming occurs when the melt goes down the warmer roof and freezes at the eaves where it is significantly cooler since it is beyond the insulated wall/attic. Another thing to do is if you have a full attic is not insulate the roof, only the ceilings them selves. If the home has vaulted/cathedral ceilings or the attic space is utilized for living space then proper vent must be used by code to help prevent ice/snow melt. I have also seen contractors use 2" foam insulation with fiberglass under it for heat transfer to the roof.
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Old 12-26-2008, 01:33 AM   #22
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Re: Ice Dam HELP


Sorry. I misread your post. Woodchuck2 summed it up though.

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Old 12-26-2008, 03:30 PM   #23
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Re: Ice Dam HELP

Originally Posted by buckeyeso2 View Post
I don't think I agree with your heat loss theory. You are right in saying that ice damming comes from heat loss, but soffit ventilation does not have anything to do with this. The attic is still going to be the same temperature, even with less vented soffit!!
I know what your thinking but did you ever hear of wind chill? Ceiling insulation is required to be at least xx amount of inchs right? The lower roof slope near the eaves of the most homes dont have the full insulation thickness required because of the angle so heat is lost.
For insulation to be effective it needs an air barrier like plywood walls and drywall. In an attic the barrier is one sided. Now factor in How much colder it is with a large breeze flowing over the insulation. If an air dam is constructed to block wind where the insulation comes in your golden but often the detail is left out to get air into the attic. So in my book you can acheive air circulation without allowing a full draft.
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Old 12-26-2008, 03:45 PM   #24
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Re: Ice Dam HELP

Originally Posted by Patrick View Post
I wasn't aware people till use spike and ferrules we use hidden hangers with a diagonal lag screw

The real problem with this customer is they had water around the windows. We looked at their old siding and windows, and there was NO flashing or window tape, and there were gaps everywhere.
I dont use spikes either just asking. As for the window thing........This is a Warning.... Mold and moisture will be an enourmous problem because #1 homes originally sided had only one layer, #2 the walls often were plaster not paper which breeds mold and #3 Many homes were uninsulated so if any water got in dried by draft.
Flashing tape is recent. If you reside over any foam board but dont tape the seams the entire wall will allow water in. Fanfold is the worse than rigid boards but as water rolls down into a jay channel over a window it will need to bleed down the wall to get back out the siding. Residing allows a million more places for water in. We need to stress these things at the sale because proper details take time.
I used to do roof and siding with a 3-4 guys when the guys started putting 6-8 guy on roof for one day completion I focused more on siding. Now those guys are doing the siding too and a alot of quality is lost to speed.
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Old 12-26-2008, 06:37 PM   #25
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Re: Ice Dam HELP

so tom your saying air is blowing thru the insulation instead of over it ?
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Old 12-26-2008, 09:59 PM   #26
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Re: Ice Dam HELP

tom m.

i beg to differ. i agree that you do not necessarily want gale force winds blowing through your attic, but reducing or blocking soffit vents is definitely NOT the answer to solving the ice damn issue.
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Old 12-27-2008, 09:56 AM   #27
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Re: Ice Dam HELP

Kind of a homegrown way of clearing ice dams.

Clear 4-5 feet of snow off the roof as described earlier.

Hook up a garden hose to your water heater or boiler.

Place the hose in the center of the gutter where the water will flow to both outlets.

this will take a little while to clear but will save you the trouble of replacing a ton of sheetrock and painting ceilings.

I have never done this to a customers house ( fear of messing with their hvac and breaking it, I put it off to a roofer that I know) but it works every time to my house, and in New England I have done this plenty.

Now I am going up to the attic and looking at the insulation and see if I can't fix it once and for all.


Last edited by Jayrek; 12-27-2008 at 10:03 AM.
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