Comments on: Ice Dams prevention & ventilation of low-slope roofs

By: Mike

Mike — Sat, 09 Jan 2010 01:04:50 +0000

I’m upstate NY where we get an average of 5′ of snow a year. I had a new asphalt shingle roof installed about 5 years ago with the rubber barrier and ridge vent. Last year we added a sun room of the back of the house (we have a ranch style house) where the roof meets from the house to the sun room (on both sides) I get ice dams. Stats in the gutters and works back, I have blown insulation in the attic. Any suggestions?

By: Leo

Leo — Thu, 31 Dec 2009 21:06:38 +0000

Rod, If you want to "advertise" your company, please do not post spam-like comments with your website. The comments are for people to post genuine feedback / questions / suggestions or to disagree. We have a construction directory where you can list you company in appropriate category. Simply use our form to add URL to green building directory.

By: Rod Pennington

Rod Pennington — Tue, 29 Dec 2009 20:24:29 +0000

If you live in the north you are going to get ice dams. The first thing to do when you have an ice dam is to open a channel in the ice to drain away the water and stop leaks into the house. A refillable snow melt sock or ice melt sock thrown on the roof and pulled into place will open a channel in minutes.

Insulating properly goes along way to prevention of ice dams and there are many other expensive engineering solutions, but most of them kinda make you think about the story of the truck wedged under the bridge and how nobody could figure out how to pull it out until a little boy said, “Why dont you just let some air out of the tires and drive it out.”

By: Massachusetts Roofing – recent flat and metal roofs which we installed in MA.

Mon, 23 Nov 2009 06:32:04 +0000

[...] How to prevent Ice Dams – comprehensive guide on which focuses on the root cause of Ice dams which is usually a combination of poor ventilation and and inadequate insulation in the attic space or between roof rafters. This guide will help homeowners minimize heat leaks in the attic, improve ventilation and eliminate the effects of ice dam leaks by installing a Metal Roof or an IB low-slope roofing membrane. [...]

By: Residential IB Flat Roofs in MA, RI and CT: Green and Solar PV cool roofing | Cool Flat Roof - MA green roofing company

Sun, 28 Jun 2009 22:15:30 +0000

[...] roofing membrane is perfect way to eliminate Ice Dams on a low slope roof, as it is a seamless blanket over entire roof. Hot air welded seams prevent water from backing up [...]

By: Rubber flat roofing - why you should avoid using EPDM for your flat roof home. | Cool Flat Roof - MA green roofing company

Sun, 28 Jun 2009 21:54:56 +0000

[...] insisted that the rubber is a good choice for a low slope shed dormer (without mentioning the poor low slope roof ventilation and ice dam prevention associated with shed dormers). They also mentioned that rubber is a good choice for a flat roof [...]

By: admin

admin — Mon, 08 Jun 2009 20:53:03 +0000

Sam,

From my experience and from what I’ve read in the reliable/credible building construction sources, a Ridge / Soffit vent system should not be combined with any other type of ventilation, and those other vents (passive box / can vents in your case) violate the flow /circulation of warm air in the attic and air in some cases either just stays there “spinning” inside attic or very little circulation occurs or parts of the roof are not being vented.

Basically, if you have enough intake through the soffits, and a decent ridge vent, your roof should be ventilated just fine without the need to use any static or power vents. For ridge vent, I like the one that is corrugated plastic from Owens Corning and other brands as it does not obstruct the flow of air, where is a very “popular” Cobra from GAF allows less air to pass through.

For more information on attic ventilation you should check out these sites:

http://www.toolbase.org/Design-Construction-Guides/Roofs/ice-dams – General guide on Ice dam prevention and just a very good source of construction techniques and building product references.

http://roofersreview.com/Ventilation – a very good source for various ventilation issues and solutions.

http://www.roofing.com – Very good source for any roof-related questions. It is a forum with many knowledgeable and responsible roofing contractors, and I’m a frequent contributor there, under nic-name LAMetalRoof.

By: Sam Dorchen

Sam Dorchen — Mon, 08 Jun 2009 20:37:22 +0000

In standard steep slope (4/12 or steeper) roofs I have ventilated the attic space in accordance with the IRC and have used soffit, ridge and roof can vents. Lately I’ve been advised that the best feature for the upper third of the roof is ridge venting. For roofs with large areas and where ridge venting can not supply the required free area I have used ridge vents and roof cans placed in the upper 1/3 of the roof. This method allows the soffit and upper 1/3 venting free area to be equal or balanced. However, I’ve been told that the use of ridge vent and roof cans is not recommended because the movement of air through the ridge vent will draw air through the roof cans and diminish the amount of air coming through the soffit venting. Please comment on the combined use of ridge and roof can vents.

By: Low slope roofing and shed dormers

Low slope roofing and shed dormers — Tue, 26 May 2009 02:00:47 +0000

[...] metal roof could be used to solve the constant roof leaks and ice dams on such low slope roofs, but in this particular case (the picture above), the pitch of the roof is [...]

By: Meghan Huestis

Meghan Huestis — Tue, 21 Apr 2009 13:03:00 +0000

Good day, I was researching ice daming for work and as someone who has had the problem over the winter I found the info to be very informative. I have ann older minihome with flat roof, 1970 roof! I have had 3 contractors come look at it and all have recommended rubber roofing. None have mentioned how to prevent ice daming so this article was very informative. Thank you!