I need a new roof on my 1962 vintage home.
One bidder says they will install 3′ of Grace ice and water shield around the lower edge of the roof. Another says 6′.
I looked at the Grace web site and it says to base the amount you use on a number of different variables including climate, slope, degree of ventilation of the roof space, etc.
We’re located in southeast Wisconsin and winters can bring a good bit of snow. The house has overhangs that vary, but some are up to 30″. The pitch is not too steep to walk on and I believe that it’s pretty well ventilated (ridge vent is in place now and there are a number of soffit vents).
Any recommendations? I’m even wondering if 6′ is enough.
Thanks.
Replies
Have you had any ice dam problems in the past? With the 30" overhangs you might want to consider the 6' width. Is it that much of a cost difference? It's really a matter of the material cost, the labor shouldn't be that much more.
Ice damming usually begins to leak a couple of feet in from the wall line. Go with the six feet of I&W. Definitly. You won't regret it.
John
Correct me if I am wrong but ice damming is caused by the lack of constant air temperature, which is caused by poor ventilation.
Now at $80 to $100 a roll, I think 6 feet is unnecessary. If the roof is ventilated properly, then 3 feet is not needed as well.
I love this stuff, but I feel people use it too much "just to be safe". I use it in all valleys, but not on the end. We did not have this great material 100 years ago and there are many roofs that remain without ice damming because of proper ventilation. Unfortunately I have seen entire roofs covered in this stuff.
Kyle
I think Grace recommends not to cover the entire roof with Ice and WatersheildMike
It's O.k. to think out of the box, Just don't walk off of the plank!
They say not to do the whole house? They do it all the time on custom mountain homes here in colorado. I would say on nicer homes, it is the norm rather than the exception. In fact, our entire roof has it....so now you have me worried!
Is Piffin out there? Did you do this in Telluride?
Paula
Edited 5/6/2002 12:50:22 PM ET by Paula
Stop worrying, your roof is OK.John Svenson, Builder, Remodeler, NE Ohio (Formerly posted as JRS)
Paula,
I'd trust Svenny's expertise
I went to the Grace web site. The data sheet does say that you can apply the membrane to the entire roof deck
http://www.na.graceconstruction.com/product.cfm?mode=c&did=8&id=63#727
Sorry for the scare, but I still vaguely remember reading something to the contrary.
Mike
It's O.k. to think out of the box, Just don't walk off of the plank!
Edited 5/6/2002 5:05:46 PM ET by Mike S
Edited 5/6/2002 5:07:38 PM ET by Mike S
Thanks guys. I guess thats one less thing I'll worry about. That only leaves 4,098,223. .....
vent cathedral or not vent......acid stain or something different....power wash logs or sand....declare bankruptcy and walk away free or stick it out..... :-)
Paula
One more comment on the ice and water issue. Even with proper ventilation it's still possible to get ice damming. We've seen problems in the past on a couple of houses tucked tight into a steep hillside on the northeast side of the hill. On frigid days in winter when the sun shines in the morning {doesn't happen to often here} it will melt snow on the roof but before it's melted off the sun is gone down over the hill for the day by lunch time. This starts up the ice damming even tho there is plenty of ventilation in the attic.
Bish
About the old days...
An old timer, up in the Adirondaks, once told me that they used to figure about "one cord of wood per foot of snow". In other words, their lack of insulation caused ALL the snow on the roof to melt, at a rate of about a cord/foot(depth).
Supposedly they did not have much ice damming in the old days because it melted off so quick. I guess it could work if your overhangs were real short (and your fuel supply was infinite).
Those big condos at the mtn village? The ones with lots of barrel tile? And dozens of skylights?
You bet your bippy we did!
Excellence is its own reward!
Hmm,
Most homes built 100 years ago leaked like sieves (therefore the roof's were cold( unfinished attics)). The house was not insulated nor was the attic. I live in a house that was built in 1931 and when I finished the attic I got ice dams (new insulation with baffles to allow air flow, ridge vent, roof vents and continuous soffit vents). Use Ice and water shield as much as you can afford. Getting a Cold Roof is an iffy proposition
John is right on. The general rule of thumb is 3-4 feet inside the wall line, because that is where heat rises and hits the roof causing melting, and re-freezing.
In addition, I would recommend that the same stuff is applied to all valley's and around all perforations of the roof.
I'm in Moscow, and we use it up here a lot.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1927
I'd go with six foot.
our rule of thumb is three feet beyond the wall
Excellence is its own reward!
Is the 30" overhang measured horizontally, or along the rake ? The rake measurement could be significantly more then the horizontal length on a steep roof.
Redneck Extraordinaire
As was said , if you had no ice problem before, 6 feet may be excessive. I build in N.E. wisconsin & U.P. of Michigan. Our general rule of thumb is that it should extend up the roof to a point at least 1 foot inside wall line below. This is actually a code requirement in my area of MI. If ice problem existed before, 6 feet is a good idea. Much easier to put it on now, than to tear off to add later. I would verify that your ventilation is proper, regardless. IMHO ice & water is an expensive product, but effective. I also only use Grace, if customer wants a cheaper brand, my warranty is out of there. Good luck.
Brudoggie
Thanks to everyone for the tips on ice and water shield.
It turns out that the bid including 6ft was less than the one that only included 3ft. Other aspects of the bid were comparable and the references checked out too.