Ice Gaurd membrane

[Brian A. MacNeish]

Robert:

"A balanced ventilation system is absolutely critical to the life of the roofing system, both for winter and summer"

Just because these companies sell roofing materials, does not mean they have a fully up-to-date technical staff that has re-trained in building science!!! I have found these types are some of the hardest to talk to- they are so engrained in the old stuff they cannot believe that it was incomplete. Bill Rose had a Q&A spot in The Journal of light Construction about 10 years ago, where he slams manufacturers about using every excuse to avoid warranty claims when the real reasons are shingle quality. The short answer also talked about shingle temps in vented cathedral ceilings- yes, the shingles are cooler at the lower sections of the roof but near the top, they are hotter than if installed in a regular, unvented roof. You can always draw all kinds of arrows on diagrams but........will the air always go there or develop the velocity/volume needed for the hoped for effect- cooling? NO. The inspection field needs a lot of training in building science; all is not as it appears.

[Ed Fako]

I too have read all of the posts here, in addition to every ventilation technical paper I could find over the past several years of research on this subject.

There is a significant study to support the claim that shingle color has much more to do with shingle life longevity, but the fact of the matter remains, that the manufacturers REQUIRE proper BALANCED ventilation system between the fresh air intake and the attic exhaust. The ideal scenario in most cases would be weighed in favor of a 60 % intake to 40 % exhaust ratio.

If at least the proper true 50/50 balance can not be adequately achieved, either a complete "air-tight" vapor barrier must be installed on the warm side of the attic floor insulation.

If these scenarios can not be achieved, then you must DOUBLE the amount of attic exhaust ventilation to a 1 square foot per every 150 square feet of attic floor space ratio versus the standard 1/300 ratio.

Whether some experts defy or denounce the warranty tactics used by the shingle manufacturers, it remains that those are their warranty conditions which must be met.

For those that "build or roof to CODE", I personally feel that they are only doing the minimal amount necessary to meet the least minimum standard regulated, which is all to frequently not even inspected and verified in the first place.

Per GAF, Alcoa, and Air Vent; Each has stated in writing, that over 90 % to 95 % of all residential shingle roofs do not meet the manufacturers specifications for warranty approval. Unfortunately, there are no mandated manufacturers inspections required to pass along a useless piece of warrany information along to the homeowner.

I have been roofing for 29 years, and have owned my own roofing company for 23 of those years and real life experience has shown me that any reroof or roof over layering will reduce the useful and functional life of the newly installed roof system to between 12-15 years before becoming desirable to replace once again.

The actual 1/300 and 1/150 ratios come from a HUD archive document originally dated 1942, which I have a copy of.

The HVI and Air Vent, "Principles of Attic Ventilation" guidelines document very well, that a more reasonable ventilation calculation would be best though of as "air exchanges per hour instead of total NFVA intake and exhaust.

Edit add on:
Marcel made some excellent points regarding the mishaps and potential hazards regarding a re-roof over an existing layer(s) in post # 9, but to add to that would also be the pockets of hot trapped air, called heat sumps, contained in this encapsulated area, which further promote the premature deterioration of the newly installed roofing materials. Additionally, why is the first roof being roofed over in the first place? Because it is worn out! Does it then not follow suit, that the crumbling substrate will be less than desirable of a surface to install a new roof on?

Ed the Roofer

[Marcel R. Cyr]

Ed the roofer;

I like it, good job.

Marcel

[rcramer]

Hey Ed,

I like it too.

Bobby the Roofer

[Peter C. Russell]

You can post what ever you want out of a text book, but my 22 years experince in NE has taught me 1, always strip a roof and start from scratch ( even metal roof ) and 2 Always vent a roof.

[Marcel R. Cyr]

Originally Posted by prussell

You can post what ever you want out of a text book, but my 22 years experince in NE has taught me 1, always strip a roof and start from scratch ( even metal roof ) and 2 Always vent a roof.

Ditto

Marcel

[Ed Fako]

Thank you for the warm welcome guys.

Ventilation and a lack of warranty qualification just so happens to be one of my hot buttons.

Since I am not a home inspector, I have not actively posted in this forum, but I like the technical disection of many of the exterior aspects of the building envelope.

I moderate and frequently post on another site called ContractorTalk dot Com and to a lesser degree at JLConline dot com as well. But, it always remains stimulating to find an additional outlet to further expand my data and knowledge resources from.

I added some additional information in my earlier post via a current edit too, referring to some of Marcels valid information.

Ed

P.S. How do I go about getting my User Name changed to Ed The Roofer, which is the name I use on all of the other forums I participate on?

[Marcel R. Cyr]

Ed the Roofer,

Welcome.
Wish I could help you in how to change your name, but I am not much of a guru when it comes to computers. ha. ha. I am sure someone will chime in to help you.

Marcel

[Ed Fako]

It is a VBulletin administrator task. I asked the administrator on the ContractorTalk Dot Com forum where I moderate at, and he told me to email this boards administrator and request it, so I did.

He said it is no problem to do, if someone here actually does read my e-mail.

Ed

[rcramer]

Hey Ed,

I didn't even notice you were a new user.....anyway... Welcome aboard! and good post. Like Marcel and Peter clearly pointed out, nothing beats experience.

[Ed Fako]

Actually, I signed up 3 months ago, and posted a couple of times, but my old computers hard drive crashed, and it took me a while to catch up on tasks and importing my Favorites Sites previously bookmarked was not high on the priority list.

Getting Somewhat Back to Topic:

I am compiling a consumers/contractors pro's and con's booklet from website sources I can refer to and reference, which will produce a good "Point-CounterPoint" analysis about all exterior factors especially regarding roofing, ventilation, rain carrying systems, and all of the different types of flashings which should be required to be installed on a roof. Residential primarily, but commercial info will be inputted as deemed necessary.

Any links that you could provide would be greatly appreciated. (This winds up being my off season, winter project to compile and edit the articles.) I particularly like actual real world studies, technical reports from manufacturers and the related associations, and white papers.

If you want to store my e-mail address for just such an instance that you come upon something noteworthy, please forward it to

Ed Fako
Right Way Roofing Company

e-mail address: eddiesdad@sbcglobal.net

Thanbk You.

[Brian A. MacNeish]

Marcel:
"Ventilation plays a big role on the life of a roofing shingle, because it overheats and basically cooks and you loose a lot of life."

I'm thinking that virtually no one on these boards have ever had a subscription to the newsletter Energy Design Update or if they had they did not believe what they read. In the July 2006 issue (I believe;can't find my copy at the moment), a Building Science Corp reseacher measured roof temps of dark roofing materials in Jacksonville, FL during the month of August. Yes, he found that the unvented roofs had higher temps at their surface (the hottest part of the shingle since the sun hits there) but over the month the average temp rise on the unvented roof surface was something like .2 degrees F, not likely to cause shingle failure.

This excerpt from atechnical paper (Ventilation) on the Canadian Roofing Contractors Association is instructive to what's going on.......they speak against the shingle manufacturers and their warranty! practices!!

"The Canadian Asphalt Shingle
Manufacturers Association has issued a
bulletin titled “Proper Ventilation for
Asphalt Shingle Covered Roofs”. In it they
state that both heat and moisture build-up in
attics is the primary cause of many roof
problems including blistering, distortion and
curling of the shingles. It has been
theorized (where's some proof???.....We can theorize forever about anything... ed by BAM) that poor ventilation of attics can
cause excessive heat build-up and high deck
temperatures. Since heat is the major
contributor to the aging of materials, this
heat build-up is said to contribute to the
deterioration of many roof-covering
materials. Although a recent study by
Simpson, Gumpertz & Heger Inc.,
demonstrated that geographical location,
building orientation, and roof colour have
far greater influence on roof surface
temperatures than the ventilation below,
inadequate ventilation is often cited as the
reason for roof performance problems.
Material manufacturers may not honour
warranties where it can be shown that there
is insufficient ventilation of the space below
the roof."

See http://www.roofingcanada.com/techbull/volume53e.pdf

There are some other gems in this paper! Since contractors are a very, very conservative bunch, they don't go as far as some do in reducing the emphasis on attic ventilation as a solution to many problems. But it was interesting how far they moved the bar into the new building science. It also was interesting at our last quarterly local HI meeting at which one of the largest roofers in our city was the guest presenter. After about 5 minutes of speaking about roof problems relating to condensation, venting, etc, he pointed to myself and said "if you want keep current on this stuff, talk to Brian. That was quite funny to myself since the HI responsible for guest speakers was one I had been arguing on this topic for a few years (but would refuse to read any suggested papers, preferring to talk to some small, back of a 1/2 ton roofers for his info!!)

The above issues have been researched and changes are being made in literature here in Canada.
See http://www.cmhc-schl.gc.ca/en/co/mah...gemare_001.cfm

[Ed Fako]

I am familiar with and even partially agree with the color and building orientation vs ventilation aspects being debated and providing alternative conclusions than those accepted by the shingle manufacturing industry.

But.

The fact still remains that if the product is not installed per the manufacturers specifications, the warranty validity in regards to related issues of the same, will be placed in peril.

Ed

[Marcel R. Cyr]

Brian; good article.

I am well aware of the affects of poor attic ventilation and it's detrimental affect on roof shingles.

The initial question was double layered roofing approved by Code.

The combination of the double layered roof system and poor ventilation by all means will take half the life span of roof shingles away in a heart beat. Proven, seen and fact. Not very hard to understand when one has spent his life in it's surroundings.

Your point is well taken and hope that all appreciate our input into this matter.

The problem with today's Construction World is the fact that everybody does just one thing and do not see the whole panorama picture if you know what I mean.

The guy that does the siding will only do that aspect of the work and install it on whatever and not think twice because he was paid for that particular item only.

The roofer by night will roof your house over another layer and not even question it and I would be surprised if he even read the directions.

The concrete guy, will pour his concrete with complete disregard to the splattering and what effort it will take to clean it up after he is gone.

I could go on and on, but I am sure you get the message.
I am not trying to knock anyone, just trying to make a point of such that people do one aspect of the job and sometimes have no peripheral vision of what is going on.

That is why, we as Home Inspectors get hired to notice these things and be able to intelligently identify the problems caused by such narrow visions.

Every one of you on this post have dedicatedly shown a vision that others may appreciate. And I thank you all for that.

Good job of all of you.

Thanks.

Marcel


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[Peter C. Russell]

Marcel, you make an excellent point,
I recently gave a deck presentation to my local chapter, not that anyone new about it, but that another story. Anyway on of my points was when building a new home the framers sometimes install the decks and if your lucky they may use copper flashing where the ledger board meet the house.
Now along come the vinyl siders and they drive aluminum nail through the copper flashing for their siding thus causing a chemical reaction between the copper and aluminum, then the flashing deteriorates within months and the water is now going behind the ledger board and within a year starts rotting out the sheathing then the rim joist.

Huge problem that every inspector should be aware of
Thanks for bringing that up.