Comments on: Blocked Proper Vents Causing Ice Dams http://www.homeconstructionimprovement.com/blocked-proper-vents-causing-ice-dams/#utm_source=rss&utm_medium=rss&utm_campaign=blocked-proper-vents-causing-ice-dams Expert Home Improvement Advice Sun, 12 Feb 2012 23:48:06 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Toddhttp://www.homeconstructionimprovement.com/blocked-proper-vents-causing-ice-dams/#comment-53691 Todd Wed, 26 Jan 2011 02:55:56 +0000 http://www.homeconstructionimprovement.com/?p=1846#comment-53691 Lynn - Well first of all ice dams are the result of two issues, one heating entering the attic and two poor ventilation. So yes adding insulation is a good idea but addressing the ventilation is just as important i.e. ridge vents and soffit vents.Typically there's not much you can do under the A/C unit, however, you can create a frame around it and increase the insulation around it. Lynn – Well first of all ice dams are the result of two issues, one heating entering the attic and two poor ventilation. So yes adding insulation is a good idea but addressing the ventilation is just as important i.e. ridge vents and soffit vents.

Typically there’s not much you can do under the A/C unit, however, you can create a frame around it and increase the insulation around it.

]]> By: Lynnhttp://www.homeconstructionimprovement.com/blocked-proper-vents-causing-ice-dams/#comment-53690 Lynn Wed, 26 Jan 2011 01:58:48 +0000 http://www.homeconstructionimprovement.com/?p=1846#comment-53690 Any advice on adding more attic insulation around a big air conditioning unit? We definitely need more insulation up there to stop the icicles and damming. How do we keep it tight up there with the air conditioning unit? Any advice on adding more attic insulation around a big air conditioning unit? We definitely need more insulation up there to stop the icicles and damming. How do we keep it tight up there with the air conditioning unit?

]]> By: Handymanhttp://www.homeconstructionimprovement.com/blocked-proper-vents-causing-ice-dams/#comment-53563 Handyman Thu, 20 Jan 2011 05:00:45 +0000 http://www.homeconstructionimprovement.com/?p=1846#comment-53563 Todd seems to have a full grasp of the issue at hand. I'd like to add, though, that no matter how much or what type of insulation you put in the attic you WILL still have heat loss and unless the building is in the desert and unoccupied there will be moisture. That is what venting is for. One goal of ventilation is to keep the whole roof deck as near to outside ambient temperature as possible. This prevents snow melt from the bottom up, which results in melt water trickling down to the eave and refreezing. A good envelope around the heated portion of the building is important to prevent migration of moisture laden air but there is almost no way to eliminate the presence of moisture in the attic. If that moisture is not vented away it will condense in the insulation, thereby reducing the r-value and promoting mold, wood rot and damage to wall and ceiling panel. In the summer, attic ventilation keeps the roof deck relatively cool to improve shingle life and reduce heat transfer down into the living space. It also allows humidity to escape freely rather than becoming entrapped in a closed space right above your comfy air conditioned living space, where it could condense and cause the same aforementioned damages. Todd seems to have a full grasp of the issue at hand. I’d like to add, though, that no matter how much or what type of insulation you put in the attic you WILL still have heat loss and unless the building is in the desert and unoccupied there will be moisture. That is what venting is for. One goal of ventilation is to keep the whole roof deck as near to outside ambient temperature as possible. This prevents snow melt from the bottom up, which results in melt water trickling down to the eave and refreezing. A good envelope around the heated portion of the building is important to prevent migration of moisture laden air but there is almost no way to eliminate the presence of moisture in the attic. If that moisture is not vented away it will condense in the insulation, thereby reducing the r-value and promoting mold, wood rot and damage to wall and ceiling panel. In the summer, attic ventilation keeps the roof deck relatively cool to improve shingle life and reduce heat transfer down into the living space. It also allows humidity to escape freely rather than becoming entrapped in a closed space right above your comfy air conditioned living space, where it could condense and cause the same aforementioned damages.

]]> By: Toddhttp://www.homeconstructionimprovement.com/blocked-proper-vents-causing-ice-dams/#comment-43915 Todd Tue, 25 May 2010 00:30:51 +0000 http://www.homeconstructionimprovement.com/?p=1846#comment-43915 Tim - The general rule of thumb (this can change depending on your local building code requirements, which you should check) is 1 sq. ft. of ventilation per 150 sq. ft. of attic space. Your attic is roughly 650 sq. ft. which means you should have at least 4.3 sq. ft. of net openings. A 1 inch diameter hole has approx. 0.02 sq. ft. of opening. If you take 4.3 sq. ft. required and divide by 0.02 sq. ft. supplied you would need 215 1-inch diameter holes to provide sufficient eave ventilation. You would also need the same sq. ft. in the ridge vent. make sense? Sounds like you only have 8 sections times 3 holes which is only 0.50 sq. ft. of ventilation.If you installed a 2 inch wide strip vent along the length of the soffit you would have plenty of ventilation.Make sense? Tim – The general rule of thumb (this can change depending on your local building code requirements, which you should check) is 1 sq. ft. of ventilation per 150 sq. ft. of attic space. Your attic is roughly 650 sq. ft. which means you should have at least 4.3 sq. ft. of net openings. A 1 inch diameter hole has approx. 0.02 sq. ft. of opening. If you take 4.3 sq. ft. required and divide by 0.02 sq. ft. supplied you would need 215 1-inch diameter holes to provide sufficient eave ventilation. You would also need the same sq. ft. in the ridge vent. make sense? Sounds like you only have 8 sections times 3 holes which is only 0.50 sq. ft. of ventilation.

If you installed a 2 inch wide strip vent along the length of the soffit you would have plenty of ventilation.

Make sense?

]]> By: Timhttp://www.homeconstructionimprovement.com/blocked-proper-vents-causing-ice-dams/#comment-43910 Tim Mon, 24 May 2010 16:11:57 +0000 http://www.homeconstructionimprovement.com/?p=1846#comment-43910 Todd,I have a question for you that the manufacturer can't/don't want to take the time to answer. I had a contractor add aluminum soffit to my house for appearance but more for added ventilation. Every 46" or so they drilled (3)-1" holes in the wooded soffit and installed a 12"x6.5" vented section of aluminum soffit that has a free air space of 13 sq inches per 1 LF. So it appears that I won't be getting the 13 sq in due to the 6.5" not being 12" and the 1" circles instead of the entire vented area being. The million dollar question is what is each vented area rated at for airflow into the attic? The area of the attic above garage and family room is 34'x21' so gut feeling is I don't have enough airflow coming in (only one side of house has soffit). There are 8 sections of the vents also.Thanks,Tim Todd,

I have a question for you that the manufacturer can’t/don’t want to take the time to answer. I had a contractor add aluminum soffit to my house for appearance but more for added ventilation. Every 46″ or so they drilled (3)-1″ holes in the wooded soffit and installed a 12″x6.5″ vented section of aluminum soffit that has a free air space of 13 sq inches per 1 LF. So it appears that I won’t be getting the 13 sq in due to the 6.5″ not being 12″ and the 1″ circles instead of the entire vented area being. The million dollar question is what is each vented area rated at for airflow into the attic? The area of the attic above garage and family room is 34′x21′ so gut feeling is I don’t have enough airflow coming in (only one side of house has soffit). There are 8 sections of the vents also.

Thanks,

Tim

]]> By: Toddhttp://www.homeconstructionimprovement.com/blocked-proper-vents-causing-ice-dams/#comment-42618 Todd Mon, 22 Mar 2010 17:30:07 +0000 http://www.homeconstructionimprovement.com/?p=1846#comment-42618 Jonathan - I have to disagree with you. Ventilation is crucial unless you want to "spray foam" your attic as your company (I removed your link as I find it to be spam) wants to sell. I will agree that ventilation is not needed if you can completely seal the space with foam. However, if you use other insulation methods the ventilation is 100% required as proven by the millions of homes with proper ventilation. Jonathan – I have to disagree with you. Ventilation is crucial unless you want to “spray foam” your attic as your company (I removed your link as I find it to be spam) wants to sell. I will agree that ventilation is not needed if you can completely seal the space with foam. However, if you use other insulation methods the ventilation is 100% required as proven by the millions of homes with proper ventilation.

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