# Tar paper over Ice & Water Shield (under comp)?



## A&E Exteriors (Aug 14, 2009)

As long as the instructiins are followed and all the ventilation is proper and functioning they last as long as they say. My best expierences have been with Certainteed Landmarks and Malarkey Highlanders. 

Highlanders are my new favorite. Very tough and almost leathery


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## A&E Exteriors (Aug 14, 2009)

If you really want to overkill it use Grace I&W and synthetic


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## SouthonBeach (Oct 18, 2012)

BuilderBumm said:


> Frankly, I've been telling this customer that they should let us do a metal roof for them. I have ill feelings about today's composition shingles. It seems that the warranties "look" great, but in reality the warranties are pretty light weight and it looks as if today's composition shingles don't last very long - no matter what the warranty is.
> 
> Do today's shingles need replacing far sooner than one would expect? ie: a 30 year shingle only lasts maybe 20 years, a 40 year shingle might only last 25 or maybe 30 years. Is that a correct statement?




It depends on the climate. Most areas I think they last as long as they say if you follow the guidelines on everything. 
In the hot south states. Like FL we get about 15 - 20 yrs life.


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## BuilderBumm (Apr 27, 2016)

Speaking of Malarkey, I had 20 year Malarkey's put on a rental house around 1979. Those shingles are still on that house and they look fine.

That is one of the reasons I asked if the shingles are not as good today as they were long ago. 37 years on a 20 year shingle is great, IMHO.


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## A&E Exteriors (Aug 14, 2009)

BuilderBumm said:


> Speaking of Malarkey, I had 20 year Malarkey's put on a rental house around 1979. Those shingles are still on that house and they look fine.
> 
> That is one of the reasons I asked if the shingles are not as good today as they were long ago. 37 years on a 20 year shingle is great, IMHO.


I would expect the same performance of their modern shingles. Used them a couple times and they are my first choice now. Just finished a 42 sq job with them. When I get my house I am going with the Legacy impact resistant line


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## A&E Exteriors (Aug 14, 2009)

I did a 63 sq job earlier this year that had 20 year OC 3 tabs on it that lasted 28 years and I credit the ventilation for their lifespan.


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## PatChap (Jun 1, 2012)

Who knows how long theyll last. Ive torn off 12 year old and 30 year old shingles. 
Use a good brand, install them per specs and youve helped them along as best you can.
The synthetic over the ice and water is cheap insurance and makes the roof removable. You can get some very good and low cost synthetics that are only slightly more expensive than #15. 
If your able to get a certified roofer, you should be able to get them a real full warranty rather than the standard limited warranties.


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## ScipioAfricanus (Sep 13, 2008)

4" may be the "standard" but what does the manufacturer of the roofing material say is the lowest pitch the comp. should be installed over?

Andy.


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## A&E Exteriors (Aug 14, 2009)

scipioafricanus said:


> 4" may be the "standard" but what does the manufacturer of the roofing material say is the lowest pitch the comp. Should be installed over?
> 
> Andy.


2/12


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## joe karakas (Sep 12, 2016)

BuilderBumm said:


> We are working with a customer on a big remodel in a windy / wet location. Their roof is a 3.5 / 12 pitch. They are insistent on having a composition roof installed over new 3/4". I've been "trying" to convince them to install a mechanically seamed standing seam metal roof, but they like the look of comp better.
> 
> Our roofer is reluctant to install comp on a 3.5 / 12 pitch, as the National Roofing Association says 4 / 12 or steeper, only.
> 
> ...


never install ice and water shield over an entire roof! your plywood deck needs to be able to expand and contract. this is roofing 101.
if your only installing ice and water shield on a flat attachment then you can be safe installing ice and water over that area. installing multiple layers of underlayments creates a moisture barrier in between the layers;/ 
eliminating moisture is the goal not adding moisture


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## BuilderBumm (Apr 27, 2016)

joe karakas said:


> never install ice and water shield over an entire roof! your plywood deck needs to be able to expand and contract. this is roofing 101.


OMG! Too late. The roofers put down the I&W and covered with a double layer of felt - then comp shingles. That said, we hav a lot more air vents than the calculations called for.


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## Golden view (Feb 16, 2012)

That's not roofing 101.


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## Metro M & L (Jun 3, 2009)

304?


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## BuilderBumm (Apr 27, 2016)

joe karakas said:


> never install ice and water shield over an entire roof! your plywood deck needs to be able to expand and contract. this is roofing 101.


As we covered the trusses with 3/4" plywood we used metal H spacers between each sheet plywood for expansion. A lot of roofers use I&W on the complete roof around here. We also called Certainteed and asked them is complete coverage is OK. They said yes.

Certainteed calls it out as OK: "MetaLayment is a vapor barrier. Therefore, if MetaLayment is applied over a majority of the roof deck, proper deck ventilation must be provided". 

So to do this, we spaced the plywood with H clips and created a great ventilation system - far better than the minimum standards.


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## Golden view (Feb 16, 2012)

Golden view said:


> That's not roofing 101.


Roofing 101 is start at the bottom:laughing:

I see plenty of commercial jobs with I+W all the way up. And I'm sure it can move as much as plywood.


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## SouthonBeach (Oct 18, 2012)

joe karakas said:


> never install ice and water shield over an entire roof! your plywood deck needs to be able to expand and contract. this is roofing 101.
> 
> if your only installing ice and water shield on a flat attachment then you can be safe installing ice and water over that area. installing multiple layers of underlayments creates a moisture barrier in between the layers;/
> 
> eliminating moisture is the goal not adding moisture




Don't do roofing in Florida then. It's in our building code book to I&W the whole roof as a way of hurricane mitigation. 
The other is 4" tape on all seams, 2 layers of felt nail 6"/12" oc with 1" cap nails. 

The smart roofers do put a layer of felt over the I&W for easy shingle removal the next time.


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## A&E Exteriors (Aug 14, 2009)

SouthonBeach said:


> Don't do roofing in Florida then. It's in our building code book to I&W the whole roof as a way of hurricane mitigation.
> The other is 4" tape on all seams, 2 layers of felt nail 6"/12" oc with 1" cap nails.
> 
> The smart roofers do put a layer of felt over the I&W for easy shingle removal the next time.


I noticed the synthetic over the ice guard also keeps it substantially cooler


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## A&E Exteriors (Aug 14, 2009)

BuilderBumm said:


> OMG! Too late. The roofers put down the I&W and covered with a double layer of felt - then comp shingles. That said, we hav a lot more air vents than the calculations called for.


You're fine. Don't listen to that reteard.


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