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  • Need ice daming solution

    I'm having ice daming issues on a new house. I plan to add more insulation (have R-49 now) to completely cover the HVAC ducting in the attic. But to eliminate the warm air in the attic (approx 39-40 deg when the outside air is 10 deg) is there anyone who makes a fan system to evacuate the warmer air in the attic? There is great ventilation at the soffets and I would assume that the warmer air being evacuated by a fan would be replaced with colder air. I have a heat activated fan at the top of the roof but that is for the summer and it is covered with snow now.

    Thanks

  • #2
    Re: Need ice daming solution

    You might get a better response to this in the construction forum. I dont know of anything on the market, but thats such a good idea surely there has to be something out there commercially available. I'll bet Garager would know.

    You could use your existing fan and add a couple hundred dollars worth of HVAC controls. It would work great and be completely adjustable.

    Andy

    Comment


    • #3
      Re: Need ice daming solution

      Without seeing the vent layout/design and pitch of your roof, it's hard to say. I assume you have a ridge vent, and I assume that your gutters are properly installed to hang below the roof edge.

      Regardless, I can say without hesitation that with a conventional asphalt roof, ice damming is the norm during the winter months.

      Upgrading to a metal roof, preferably aluminum which will shed snow the quickest, is certainly a long term solution to avoiding ice damming.

      Then again, I haven't seen your place - the roofline/pitch/ventilation/gutter considerations may contribute to ice damming regardless of how you attempt to rectify the situation.
      I'm on "The List" and I love it!!

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      • #4
        Re: Need ice daming solution

        There is a saying that to much ventilation can be bad. And its true, what would happen is this warm air will act like the chimney effect, it'll down draft or swirl around. If you have a ridge vent and soffit vents, that should be adequate enough.

        You need to tackle your heat source, now. Slow that heat down, so your venting will work properly and not be over whelmed. Any insulation touching the underside of your roof deck, must be moved away by at least 1".

        Air flow works great when its running up between the rafters all the way up to the peak, this keeps the underside cool. To have air flowing from one gable vent and out the other, won't keep the underside as cool as ridge/soffit vents do.

        Power vents on a temp sensor, I have installed a few in my days and the biggest problem is the noise, they sound like jet engines. It'll bother you trying to sleep at nights.

        If for some reason you don't have a ridge vent, you may wanna look into installing twirly birds, they work good with soffit vents. But you don't want, ridge/soffit and gable vents, this causes the chimney effect, and won't vent properly. Ok, I'm winded out and done....
        Great Link for a Construction Owner/Tradesmen, and just say Garager sent you....

        http://www.contractorspub.com

        A good climbing rope will last you 3 to 5 years, a bad climbing rope will last you a life time !!!

        Comment


        • #5
          Re: Need ice daming solution

          I should also add, do not chop the ice off your roof. There are these big tablets and I mean big. True Value or maybe an Ace hardware store sell these things in a bucket container. The price is around $20.00, throw these up above the ice and the will slowly melt the ice down to nothing. This will not harm any vegetation down below, but I can't remember the name of the stuff, I'm having a brain fart right now....

          I also have issues with rain gutters, they will cause ice problems too. I personally will not add them to my house, unless its a non heated room down below, such as a enclosed back/front porch. This is a big/huge debatable problem. If your foundation and landscaping slope, was done properly, you do not need the gutters. Gutters in winter, kills the bottom 2 ft, even with Ice and Water protection under the shingles. As tinmack suggested, metal on the roof is the way to go when you live in a Northern area.I do about one asphalt roof, to every 4-5 metal roofs up here now. All you have to do is drive around town and look for metal roofs, when you find one, look at the neighbors roofs, and you'll understand....
          Great Link for a Construction Owner/Tradesmen, and just say Garager sent you....

          http://www.contractorspub.com

          A good climbing rope will last you 3 to 5 years, a bad climbing rope will last you a life time !!!

          Comment


          • #6
            Re: Need ice daming solution

            http://www.roofmelt.com/
            I'm on "The List" and I love it!!

            Comment


            • #7
              Re: Need ice daming solution

              Summer is a great solution,
              but I second Garager advice.
              Push sticks/blocks Save Fingers
              ~~~~~~~~~~~~~~~~~~~
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              attributed to Samuel Johnson
              ~~~~~~~~~~~~~~~~~~~
              PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

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              • #8
                Re: Need ice daming solution

                I think the metal roofs are a great idea. I need a new roof next spring and will be looking into steel. How do todays prices per square compare with fiberglass/asphalt shingles? A couple years ago I think the price for steel was about 3 times higher, but that was when you could get a good shingle for $45 a square.

                I'm still not understanding the too much ventilation/chimney effect theory. I thought the chimney effect is what you wanted. Air entering the soffits and exiting the roof vents. It sure seems to me like just a little bit of forced air movement would make up for a lack of soffit/ridge vent.

                Andy

                Comment


                • #9
                  Re: Need ice daming solution

                  my first question is where did you get a 50 degree Delta-T from a non conditioned attic to ambient air temp? Insulating ducts is a great idea, but are they sealed? or do you have a problem with distribution loss that needs to be corrected? R-49 is great but is there a thermal bypass issue?

                  Comment


                  • #10
                    Re: Need ice daming solution

                    40 degree attic temp with 10 degree outdoor leaves a 30 degree Delta T. Im sure the difference comes from the sun beating on the roof making the attic warmer, and inadequate ventilation. I highly doubt the duct system is at fault.

                    Andy

                    Comment


                    • #11
                      Re: Need ice daming solution

                      Thanks to all who have responded. Lots of good ideas.

                      Here are some other facts: Roof pitch is 7" in 12". Asphalt shingles. House is 2 yrs old. Gutters all around. Ridge venting at top but is covered in snow (I think the ridge vents would do the job if they were exposed). No gables available.

                      I was thinking about taking the gutters off but the problem of the higher temp in the attic should be lowered first IMO. The HVAC ducting is not covered by the blown in insulation (just the insulating blankets that are normally wrapped around them...insulating guy said they are about an R-8), but I will be having additional insulation blown in to cover this ducting next week. Hopefully this will reduce the heat radiating to the attic area.

                      My possible solution now (if the added insulation doesn't reduce the temp enough) is to run 6" ducting from within 6" of the top of the attic down to an inline ducting fan (need to find a quiet, low energy fan) and then into the unheated garage via a regular register. Does this sound like it would work? This will be done only if the added insulation doesn't bring the temp down to below freezing. I'm assuming this system will bring the temp down enough to keep the attic below 32 degrees.

                      Again, thanks a bunch for your input.

                      Comment


                      • #12
                        Re: Need ice daming solution

                        Originally posted by marchboom View Post
                        Thanks to all who have responded. Lots of good ideas.

                        Here are some other facts: Roof pitch is 7" in 12". Asphalt shingles. House is 2 yrs old. Gutters all around. Ridge venting at top but is covered in snow (I think the ridge vents would do the job if they were exposed). No gables available.

                        I was thinking about taking the gutters off but the problem of the higher temp in the attic should be lowered first IMO. The HVAC ducting is not covered by the blown in insulation (just the insulating blankets that are normally wrapped around them...insulating guy said they are about an R-8), but I will be having additional insulation blown in to cover this ducting next week. Hopefully this will reduce the heat radiating to the attic area.

                        My possible solution now (if the added insulation doesn't reduce the temp enough) is to run 6" ducting from within 6" of the top of the attic down to an inline ducting fan (need to find a quiet, low energy fan) and then into the unheated garage via a regular register. Does this sound like it would work? This will be done only if the added insulation doesn't bring the temp down to below freezing. I'm assuming this system will bring the temp down enough to keep the attic below 32 degrees.

                        Again, thanks a bunch for your input.
                        You want to make sure whatever you do, that your soffit venting is not clogged up by insulation. Keep those open so that fresh air can enter the attic before esacaping through the ridge.

                        I wouldn't mess with anything other than more insulation, which is a good thing regardless of your roof situation.

                        As far as the roof, considering it's two years old, put a metal roof on when you replace it, which will probably be in another eight or ten years.
                        I'm on "The List" and I love it!!

                        Comment


                        • #13
                          Re: Need ice daming solution

                          Originally posted by Ruudacguy View Post
                          I think the metal roofs are a great idea. I need a new roof next spring and will be looking into steel. How do todays prices per square compare with fiberglass/asphalt shingles? A couple years ago I think the price for steel was about 3 times higher, but that was when you could get a good shingle for $45 a square.

                          I'm still not understanding the too much ventilation/chimney effect theory. I thought the chimney effect is what you wanted. Air entering the soffits and exiting the roof vents. It sure seems to me like just a little bit of forced air movement would make up for a lack of soffit/ridge vent.

                          Andy
                          3 times asphalt is too much for steel. Look for an aluminum shingle system. You should be able to find one for 3 times the price of asphalt. Then again, price difference is a moot point, as it's an apples to oranges comparison.
                          I'm on "The List" and I love it!!

                          Comment


                          • #14
                            Re: Need ice daming solution

                            Just curious, Where do your fart fans discharge ?

                            Comment


                            • #15
                              Re: Need ice daming solution

                              Originally posted by stokefire7 View Post
                              Just curious, Where do your fart fans discharge ?
                              They all discharge out the side of the house under the soffits.

                              The insulation guy said the soffits all look good and are not covered with insulation. We took a temp reading with an infrared gun and the underside of the roof above the soffit was 31-32 degrees (outside temp was approx 15).

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