Prevent Ice Damming On an Older Roof
LESLIE: Now this next caller has me a little confused.
Josephine, you’re in Nevada but you have a question about a home in New York?
JOSEPHINE: Correct, correct. Yes, we had bought a smaller home in New York and I’m only there for three or four months out of the year. But they never installed any flashing or anything to prevent the ice backup.
LESLIE: Ice damming.
JOSEPHINE: Well, this winter, of course we had lots of nice ice and we had backup and leaking into the house and …
TOM: Well, here’s what happened. It’s a condition called ice damming. And when you have a storm and the snow on your roof begins to melt, it melts in the roof section which is over the living space; so over the second floor …
LESLIE: Because the heat is coming up from your living space and causing it to melt.
TOM: And then all that water runs down until it hits the area just about where your exterior wall is because guess what; that overhang in the roof is part of the outside. There’s no heat over that, so that freezes and causes a dam. And what happens is that water hits that dam, it builds up, and then it backs up and goes under the shingles. Because asphalt shingles, architectural shingles, only work when gravity is doing what it’s supposed to do. But when you put the dam and it starts to back up, then that’s when it leaks and it can cause a lot of damage. I mean ice damming causes thousands and thousands and thousands of dollars of damage to homes every year.
Now the solution is a product called ice and water shield and we like a manufacturer called Grace that’s really the founder of this product. It’s called Grace Ice & Water Shield. And what happens is the Grace Ice & Water Shield gets installed on the sheathing under the roof shingles. And it’s about 3 feet in diameter and it’s sort of a rubberized material and it completely seals that area of the roof so that if water does pond there and tries to back up, it can’t get through the ice and water shield and is not going to leak into your house. But it has to be installed when the roof is first put on.
Since your roof is already on, it can also be done as a retrofit. It’s a little trickier but here’s what has to happen. The bottom 4 feet or so of roof shingles have to be pulled off the roof, the ice and water shield put on, and then the edge of the roof reshingled. It can be done. It’s best if you can do it when the roof is new but since yours is not, it can be done as a retrofit and that will solve this problem once and for all. And frankly, I’m surprised that with a home in New York, it wasn’t put on to begin with. They really should have put it on. You shouldn’t build a house without ice and water shield.
JOSEPHINE: Someone suggested this tape – electrical.
TOM: Oh, to melt the ice dams. Yeah, that’s an appliance that you have to put on your roof and have plugged in all the time and that’s pretty expensive to run. I wouldn’t recommend that over just simply improving your roof so it never happens again.
JOSEPHINE: Well, that’s what I said to my daughter, “That sounds idiotic.” (Leslie chuckles)
TOM: Yeah. I would recommend you install the ice and water shield and I think that’s going to solve your problem.
JOSEPHINE: And it’s by G-r-e-y?
TOM: No, Grace, G-r-a-c-e. You can go to GraceConstruction.com and learn all about it.
JOSEPHINE: Oh, OK. Alright.
JOSEPHINE: Thank you very, very much.
TOM: Thanks so much for calling us at 888-MONEY-PIT, 888-666-3974.
Leslie, who’s next?