Ice damming, Part 1: Insulation and ventilation
Winter’s on its way again, and along with that comes the problem of ice buildup on the roof.
That accumulation of ice can lead to ice damming, which in turn gives way to shingle damage, wet insulation, interior damage and a whole host of other problems that you certainly don’t want to deal with.
Roof icing and ice damming are both simple and complicated to understand and to deal with, so I’m going to approach it in two parts:
Part 1, where we’ll look at what causes ice damming and why insulation and ventilation are the only two real solutions to the problem; and Part 2, the pros and cons of snow removal, heat tape and other measures.
How ice dams occur
An ice dam begins with snow falling and building up on the roof. If the temperatures remain relatively low, the snow layer won’t melt. As more snow falls, additional layers build up. The new layers of snow insulate and protect the previous layers.
Simultaneously, you have the heat on inside your home. Some of that heated air gets lost up into the attic. Once it gets up there, it comes into contact with the underside of the roof.
So now two things are going on with your roof. It has an insulating layer of snow above it, and heat below it. That creates perfect conditions for the snow to begin melting from below. That allows a thin film of water to form below the snow layer, where it then runs down the roof until it reaches the eaves.
Once that water reaches the eaves, it’s past the part of the attic where the heat loss from the house is occurring, so now it begins to freeze. A solid dam of ice forms, right above the line of your exterior walls.
Now the real problems start. As water coming down the roof below the snow layer hits the ice dam, it has no where to go, so it begins to back up the roof. Since shingles are overlapped from top to bottom, there’s no protection against water coming in from below. The water begins to work its way under the shingles, and then into the house.
on the day of the tour to pick up their guidebooks.
Weather advisory
Organizers posted the following online at midweek:
You have probably seen the 90 percent chance of snow forecast for Saturday. The Christmas Foundation has spoken to each other, as well as with some of the homeowners, and we are going to push through with the Homes Tour on the 8th!
The Tour will not be rescheduled or cancelled due to snow, as there is simply no way to guarantee that the 15th will be better weather or notify everyone who has seen the 8th on our print ads, rack cards, posters, etc.
It is a risk we take in planning these events a year out, involving so many people’s schedules and Oklahoma’s unpredictable weather!
Some owners may choose to remove their home from the Tour in the case of extreme inclement weather. We will do our best to provide those details as we receive them.
PLEASE CHECK SOCIAL MEDIA OFTEN FOR UPDATES AND SHARE THE POSTS! We appreciate the help, and do not have the manpower/time to respond to 3,000 private messages asking the same questions.
As our website states, all Homes Tour ticket purchases are final and will not be refunded due to weather. Please only purchase tickets in advance if you agree with this policy. Thank you!
Holiday history
The tour is part of Guthrie’s 23rd annual Territorial Christmas Celebration, which runs with various activities through Dec. 23. Guthrie residents launched the event in 1995 with the idea of celebrating the holidays as it had been celebrated in Oklahoma Territory’s early days after the Land Run of 1889 brought in thousands of settlers. Organizers formed the nonprofit Guthrie Territorial Christmas Foundation in 2013 to help promote the celebration.
Guthrie prospered in the years after the Land Run, building up as a modern brick-andstone city with all the modern conveniences, including a mass transit system. It briefly served as Oklahoma’s capital after statehood in 1907, but lost out to Oklahoma City in a 1910 special election.
It also was spared the perils of rapid growth and misguided urban planning. So it remains a well-preserved enclave of Victorian architecture, and its central district is a National Historic Landmark.
But the clock didn’t stop in 1907, and this year’s tour will reflect that.
“We’ll have a nice mix of older and newer places,” Plagg said.