underlayment on a go-over ?

I have seen more and more "roofers" using paper and ice & water shield on go-overs Is this common ? I have never once used paper or any underlayment on a go-over. Am I missing something ? >>>

We just did a layover last week. 12:12. It was re-sheetd about 12-15 yrs ago. We pulled the vinyl siding and re-flashed one dormer and re-flashed the chimney. Added 2 vents and replaced the pipe boots. Some galvanized behemoths that were prolly 50 yrs. old. I under priced it by about $1000.

Funny thing is..... I am recieving a bunch of compliments on that darned layover! >>>

Did you do the recover with 3-tab or laminates?>>>

---Looking back over 35 years of roofing I have torn off over 1,000 residential roofs with 2 or 3 layers of comp shingles. I can't ever remember one with felt between the layers. I am sure at least one did but I don't remember. If fact, I have torn off many comp roofs over shiplap with no felt at all. As far as I can tell the lack of felt didn't seem to amount to anything. Obviously felt is a requirement today or the warranty will be void. ---Now what have I learned? For the last 60 years in my part of the country (rainy Seattle) roofers of all shapes & sizes do not apply felt between comp layers. And most all 3-tab comp roofs that were a 2nd layer lasted about 20 years which was the warranty. ---I do believe recovers lose about 15% of life expectancy. That is just a guess. I have seen many 20 year 3tab roofs go 25 years even tho they were the 2nd layer. 3rd layers do look ugly and I wouldn't expect them to last much longer then 12 years but some do. ---Laminates as recovers seem to work well. ---Obviously I am biased towards complete tear-offs. As a roofer the more work we do the more we charge and the more we charge the more we make. However, I work for the public who has quite a varied agenda. Some want quality at any cost. Others want the cheapest price. Today I sold a recover. In spite of the fact that tear-offs are better I cannot tell someone that a recover is a bad roof. How can I tell someone it is a bad roof when about 90% of the houses in the older neighborhoods have 2+ layers? Do 90% of those houses have bad roofs? If so, why do they perform so well? ---Thursday I started a job with 2 comps over wood shingles over skip. If we tear off all 3 layers we have to sheet the entire house. Add $2,000 to the bill. Well, times are tough. There is not enough money for that. So we do what is so simple. We tore off the 2 comps and recovered the original wood shingles again. We cut back the wood shingles (should have already been done by the previous recover roofer) 4 inches all around the perimeter and nailed a 1x4 in place for secure nailing on the perimeters. My helper and I did it in 2 days with me gone bidding roofs for 4 hours today. Saved the customer $2,000 and the new roof is every bit as good as either of the previous recovers that each lasted 20 years. So why not? ---Ice & water is so expensive you could almost pay for a complete tearoff. Definitely no ice & water. Lanny>>>

My comments concerned built up roofing membranes over 1 existing roof. I believe BOCA codes prohibit a recover when 2 roofs exist. We also used as a base sheet a product known as Ventsulation which was excellent and could be spot or stripped mopped. The indentations on the sheet permitted the flow of trapped gases and/ or moisture to flow to the extremeties.>>>

Let's just say it might help to consider this type of issue from something besides a box canyon point of view. Maybe lay it out like a typical troubleshooting chart would look with a flow map to help in the process. For example, take what Roofsrus1 is saying about climate. The chart would show the following fork: Roof is located in a climate zone with heavy ice and snow build-up: Yes or No. If yes, proceed to section on ice dam protection. If no, proceed to standard shingle application specs. There would be many such forks in the flow chart. One of them would pertain to recovers. Is recover an approved application by manufacturer and/or code. Yes or No. If yes, is recover an acceptable option for the contractor and homeowner. Yes or no. If yes, is the condition of the existing roof pristine or no. If no, do you mind having dirt, dust, and grit getting inter-mixed with the new material as it is being applied? If no, skip the section on felt. If yes, go to section covering underlayment options.>>>

In order to establish a good nailing base, we will install shingle underlayment and then nail our roof recover. Conditions, weather conditions, here in Oregon are mild enough that a roof covering will last twenty to thirty years per roof covering unlike other areas of this nation. That side you have other conditions that are factored in being; condition of shingles including granular condition alongside condition of roof sheeting allow us to do many, many roof recovers. That being said-do not believe or give us heck about roof recovers. Our neck of the country and its weather conditions are mild enouh that shingles will last anywhere, on recovers, from twenty to thirty years per roof covering. This allows the residential homeowner to save thousands of dollars when the time comes for their houses to be roofed again.>>>

When did allow lay overs here, we never used felt unless we were laying over wood shingles then city code made us put 30# over the wood... thery was it would make for a smoother apperance.... it still looked like cheat. :silly:>>>

Looks like Vaa and elcid did not read the question.>>>

Im a roofer from michigan your allowed 2 layers here. Underlayments on a recover is crazy and a waist of time and money.>>>

I'm right there with you Rozziroofer......Goofy, isn't it?>>>

In FL, two layers are allowed but they just don't work. In addition, if the home goes up for sale, the lender will usually not lend on a "go-over" and the roof will have to be removed anyway.

I have only sold ONE in many years of roofing-- on a barn. I can't see where underlayment would benefit either performance or longevity.>>>

Would like to debate need for a nailed base sheet when redoing a BUR. Direct attachment to an old roof w/ asphalt would mean that you would inherit any and all the deficiences of the old roof; whereas, by nailing thru the original, you would be venting any gases or moisture entrapped in old system. What say you.>>>

I thought the whole purpose of nailing over was for a cheap job. Doesn't all this unnecessary stuff kill the purpose?>>>

If I am correct, most manf. do not supply instructions for installion felt/I&W. A couple of manf. do write that they do not reccomend felt/ I&W to be installed on over-roofs/over-lays. We all know that the life span of shingles are lower when applied over and existing layer, most home owners that pay for this type of roof are quick sellers or financially strapped H/O's

The most popular reason I here why the felt is used is because it will help the shingle keep a straight course. I CAN KEEP A STRAIGHT COURSE JUST BY USING THE GAUGE ON MY NAILER! Other that, I see no reason to use the felt, maybe I will find out when it comes my turn to tear one of those roofs off!

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There you go!>>>