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Discussion Starter · #1 ·
I plan on replacing the windows,trim and siding on the two front dormers this spring I plan on covering the boarding with Ice and Water barrier rather than house wrap because of heavy snow conditions.
I plan on roofing over the existing roof (one layer) after the dormer work is complete now my question ..can I run the Ice and Water barrier out over the existing roof rather than tearing off the first layer around the dormer then fill in then re roof.
I would like to try and save the step of tear off and fill in around the dormers if I can .
Doug.
 

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Ie and water shield must be adhered to the wood substrate. IN other words, tear off the shingles and install the ice shield on the roof deck.

You should always tear off a roof anyways. Installing over an old roof is sub standard IMO. Yes it is faster. Yes it is cheaper. Cheaper and faster usually isn't better. Since this is your house, don't you want the best roof posible?

If it were my house, I'd never allow a second layer of roofing. And just to prove I am not a fanatic, many local villages are now requiring a tear off, no exceptions. Good for them!
 

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Grumpy, believe it or not, they still allow a one time shingle over here in hurricane alley.
Technically, there must be a bond break (felt) between the I&WS and the sheathing, pretty well negating the value of the I&WS.
I don't see anyone doing it and everone seems to be passing inspections so I guess that that part of the code is being ignored as it should be.
 

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Teetor that bond break is crazy. I wouldnt do it either.

Dshea, tear it off, or youre wasting your time and money with a substandard product.
 

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Between Grumpy's help and my own research I'm becoming a roofer! 3 days and 3 roofing estimators and I know more than they did. Thanks Grumpy!
I have another one coming tomorrow.
FYI, lows are about $8-9K, most are around $12K and the guy yesterday won the pot at $19.2K. That's Pinnacle Roofing, they hit the pinnacle alright. I assume that they're national, the estimator said that they were pulling in help from Grumpy's area.
 

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DSHEA,
No Grace Ice & Water Shield over old shingles. Even though it would work quite often, especially over old, flat 3-tabs we do not recommend it or want to take the risk. Clean, dry roof deck. See www.graceconstruction.com and click "Roofing Underlayments" on the left side for more info.
Jim
 

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Discussion Starter · #7 ·
Why do they require a tear off ?

Grumpy said:
Ie and water shield must be adhered to the wood substrate. IN other words, tear off the shingles and install the ice shield on the roof deck.

You should always tear off a roof anyways. Installing over an old roof is sub standard IMO. Yes it is faster. Yes it is cheaper. Cheaper and faster usually isn't better. Since this is your house, don't you want the best roof posible?

If it were my house, I'd never allow a second layer of roofing. And just to prove I am not a fanatic, many local villages are now requiring a tear off, no exceptions. Good for them!
Why the tear off requirement I could understand a load requirement or perhaps a fire safety issue if multiple layers are involved but one ..why ?
As far as my own situation I more or less knew what the answer would be cheap has got to work one of these times but not this time thanks for your input.
Doug.
 

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If GIWS is over old shingles and they move while frozen, the movement can break the seal of the GIWS around the fastener shaft. Expansion and contraction of the shingles under the GIWS can even be enough to break the seal sometimes. I wouldn't think there would be much tear-off labor, just around a dormer, right?
Jim
 

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Multiple layers will not lay very flat. Multiple layers do not allow you to identify decking issues, like rotted, cracked wood. Multiple layers are proven to not last as long as single layers. Multiple layers make diagnosing a problem more difficult if your roof ever decides to leak. Multiple layers add weight, but that usually isn't an issue.

If you do decide to install a second layer over the existing, make sure to repalce ALL flashings regardless of their current condition.
 

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Grumpy said:
Multiple layers will not lay very flat. Multiple layers do not allow you to identify decking issues, like rotted, cracked wood. Multiple layers are proven to not last as long as single layers. Multiple layers make diagnosing a problem more difficult if your roof ever decides to leak. Multiple layers add weight, but that usually isn't an issue.

If you do decide to install a second layer over the existing, make sure to repalce ALL flashings regardless of their current condition.

I only wish my competition thought like that. I do very few recovers, and the ones I do, I walk the roof with heavy heels looking for any sign of soft spots, raised sheathing, and the prior applicators straightness for a possible 'Butt-up' method. Unless I know I did the original roofing, I always pull the old flashing and install new ones, and all that picky prerequisite still doesn't mean you're roofing over concealed damage. I also will not recover English standards with metric (learned my lesson years ago with that one).


Best regards
 
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