Old 11-24-08, 06:20 PM
Thread Starter
Join Date: Nov 2008
Posts: 3
Unhappy icicles

a few months ago we insulated our attic and installed the rafter vents to ensure proper ventalation. I thought this would get rid of our icicle problem that we have had in previous years but it has not. Did we do something wrong or could it be the eavestroughs themselves (they are not plugged).
the icicles are right above our door and make it slippery, what can we do or did we do wrong and how do we solve the icicle problem?
Sponsored Links
Old 11-25-08, 04:58 AM
airman.1994's Avatar
Join Date: Dec 2005
Location: VA
Posts: 5,631
Sounds like you have soffit vents. Do you have ridge vents. This sounds like you need to increase the ventilation. Insulation will not help with the condensation.
Old 11-25-08, 03:21 PM
Thread Starter
Join Date: Nov 2008
Posts: 3
i think we have soffit vents, when you look up you see vents in the aluminum siding just before the eavestrough on the overhang of the house. We installed rafter vents in the attic, how would we get more ventilation? We do have a roof vent and we redid our roof 2 yrs ago.
thanks for your help
Old 11-25-08, 04:06 PM
airman.1994's Avatar
Join Date: Dec 2005
Location: VA
Posts: 5,631
There is a formula for venting an attic I will look for it. Do you know what the humidity level is inside your home?
Old 11-26-08, 08:14 AM
Join Date: Feb 2007
Posts: 2
Make sure there is nothing blocking those soffit vents, such as insulation. There should be plenty of air space from the soffit vent up the slope of the roof so the air can pass through the attic and out the rafter vents or ridge vents.

Here is how to calculate it.

Calculating Ventilation Area of Attic
Old 11-26-08, 08:25 AM
mikeTN's Avatar
Join Date: Dec 2007
Location: Nashville
Posts: 635
Question icicles

I don't know what an "evestrough" is. We use gutters in Tenn. to take away or re-direct water from the roof edge. If you have snow, ice, etc. build up on your roof, the sunlight will melt it and it will run down to the edge of the roof and drip off unless you have a gutter to catch the water. As it drips, it will refreeze and become icicles. Insulating the attic is great for the heat bills, as is the ventilation in summer, but the icicles are going to form at the lowest point of water run off reguardless. If the last row of shingles(your climate may require some type of insulator/water barrier) overhang into the gutter, you should not have any icicles dripping at the door.
Old 11-26-08, 06:50 PM
Thread Starter
Join Date: Nov 2008
Posts: 3
our gutters in canada are on the side of the road but for those in Tenn. they are also known as an eavestrough. The melted snow goes into and over the eavestrough to form icicles which drip in front of our door.
I will check that there is nothing covering the soffit vents but we did install rafter vents. These are a plastic vents that fit in between the rafters so you do not cover the entire area with insulation, they allow for air flow from the soffit vents.
i thought by installing these we would eliminate any ventilation problem and have good air flow.
Old 11-26-08, 07:00 PM
dhamblet's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Oct 2008
Location: PAcific Northwest
Posts: 264
Is your gutter/eavestrough freezing up and blocking water flow causing it to overflow and form icycles? Possibly use heat tape in the gutter to keep it flowing?
Old 11-26-08, 07:41 PM
Join Date: Mar 2005
Location: USA
Posts: 6,126

There are some locations (climate, geography, orienteation etc.) where some icicles cannot be prevented from the interior.

Often, warmer climate with a difficult orientation will get melting and subsequent freezing no matter what is done inside. In this case heat tape may be the onlt solution if you do not want to look at. What should worry you is if the there ice dams, which can occur with completely open gutters in some climates.

In cold climates much of the snow on a roof disappears by the process of sublimation (solid to vapor), while in other areas, the orientation and weather may freeze the water before it can be removed (slope, gutters, downspouts, etc.).

Try to look at the situation and understand what is happening. Heat tapes are not attarctive, but they are effective to melt and remove water. Often people take pictures of nice homes with uniform icicles.

If your gutters are clear, make sure you actually have good ventilation and no ice dams causing them. Just because you think you have the right setup, does not mean it is effective. - It takes detective work.

Old 12-26-08, 07:14 AM
Join Date: Dec 2008
Posts: 1
Is your door at the top of stairs going down? We added insulation last fall and still have the same problem you have. Upon further exploration, we found that the sloping roof over the stairs is the bottom of a large space over the stairs in the attic. The original builder did not put a covering over this space, but did insulate right over the space (nothing in the space). So this cavity is being heated from 3 sides and we think is causing heat to leak through the insulation causing the melting and problems over the door. We have seen some websites that say to either insulate the cavity or put plywood over the top of it in the attic floor and then insulate.
Old 12-26-08, 03:58 PM
Join Date: Nov 2001
Location: USA
Posts: 1,873
First you need to understand how icicles form at eaves. Especially since this appears to be a reoccurring problem for you. When snow is on the roof and it is below freezing outside, if the temperature rises above freezing inside your attic the snow will melt underneath the snow. The melted snow will go down your roof until it reaches an area of the roof that is below freezing, usually at your gutters or eave overhangs. At that point the melted snow will freeze and usually form icicles.

Inadequate ventilation will cause this situation but it is usually found in several places. Your description suggests that it is localized at the front door. In this case the attic by-pass or recess light fixture is the source of heat that is probably causing the snow to melt.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes