Is inadequate roof or attic ventilation a defect?

[Brian A. MacNeish]

Originally Posted by Ed Fako

Brian,
That information you posted is from the "Principles Of Attic Ventilation", by the Air Vent Corporation, who I know you despise because you feel they only want to sell more ventilation products.

Ed

The document I referred to is definitely through or from Certainteed as it was in the URL and mentioned a few times throughout the article. Maybe Certainteed owns Air Vent!!! Sneaky!! Isover Saint-Gobain is a huge multinational in the building industry.

No, I don't despise the vent people but have a healthy disrepect because they never seem to mention anything about attic airsealing to save energy, reduce the need for winter venting, and help reduce the need for a winter humidification in cold climates, all building science items.

Actually not many people seem to want to learn building science since it makes them have to read, crunch the concepts (ouch!) and, in many cases, change their minds and forget some of the BS (building science) learned at the street level. Oh! And most of these courses aren't free; they have to take time off/make time on nights or weekends and pay for their upgraded education. What a concept in an entrepreneurial capitalist system!!

Here's a quote from one of the world's foremost building scientists from the end of a talk to the Alberta Building Envelope Council AGM. (I believe):

"It was once suggested that one problem in transferring technology in the building industry is that nobody reads anything. It may be equally valid today since practitioners, as well as many researchers in building and construction seem to have neglected to read or re-read the CBD's (Canadian Building Digests), even those that fall into their respective areas of interest."

The rest of the paper is found here:
http://members.shaw.ca/alandalg/Gus_CBD.htm

Doing a search for this quote from Gus Handgord, a mentor to Joe Lstiburek, and found this from Energy Design Update (in case you haven't seen one of their articles before):
http://www.1-800-arkansas.com/energy...20Retarder.pdf

Here's a little on Gus from Building envelope forum:
http://www.buildingenvelopeforum.com/handegord.htm

[Ed Fako]

Air Vent formerly was for sure a subsidiary of Certainteed, but for about the past 3 or 4 years or so, they have new ownership, called the Gibraltar Companies.

As I stated previously, I depend on actual hands on real world observations to guide me in an acceptable direction as to the specifications I write and the installation methods we use. 29 years of roofing so far, with 23 1/2 years as a contractor have shown me many things that have worked and things that do not.

By the way, the photos I posted are typical and commonly observed during my normal estimating duties. It just so happens that I have the installation dates to correspond to the deterioration occurring. Furthermore, the decking is also prone to substantial deterioration as well, which can occur in as little of a time period as about 10 years.

The photos from the 10 year old roof with significant shingle deterioration also is displaying extremely unstable OSB deck sheathing deterioration. This decking was 100 % replaced at the time of the shingle installation 10 years ago too.

That brings up my distaste for OSB board as an acceptable replacement for exterior CDX sheathing as well. But, that is a topic for another thread.

Ed

[Brian A. MacNeish]

Originally Posted by Ed Fako

Photos of 9 year old roof with adequate or better exhaust ventilation.

Ed:

It's hard to scientifically compare shingles on different buildings with different facing slopes and maybe .........shingles from the same batch at the same plant. You and I have seen shingles from the same company installed at the same time on the same roof fail at different rates. See thumbnail below.


See the pictures at the end of this Bill Rose presentation: all shingles on the same slope and orientation and presumably from the same batch and/or shipment. How can we tell which shingles were vented or unvented?


http://www.efficiencyvermont.com/pag...0Designers.pdf

[Ed Fako]

I will only briefly comment, (Yeah right!!! ), about the photo in the thumbnail, then I will get back to looking at your link posted.

The roof in the photo has obvious individual bundles of inferior product installed.

To highlight the problem with the individual bundles, the installer put them on in the vertical racking method, thereby making the small percentage overall of the entire roof jump out at you because they are all located in the same sections of the roof.

They still would have revealed their defect in the stair step method, but it would not have seemed as prominent.

Ed

Regarding the new link you posted:
Same report, just a different source as the one I posted from the FSEC earlier on, but better color coded pages, so I saved this one also.

Page 56, the last page just verifies that the fiberglass shingle do not deteriorate as readily as the organic based shingles, especially the ones manufactured post mid and late 70's energy crisis. Do you think there is a relationship as to why older organic/asphalt shingles weathered the test of time better than the post 1970's versions? Is there more filler being implemented into the current manufacturing process of the organic shingles?

[Brian A. MacNeish]

Originally Posted by Ed Fako

Page 56, the last page just verifies that the fiberglass shingle do not deteriorate as readily as the organic based shingles, especially the ones manufactured post mid and late 70's energy crisis. Do you think there is a relationship as to why older organic/asphalt shingles weathered the test of time better than the post 1970's versions? Is there more filler being implemented into the current manufacturing process of the organic shingles?

Yes, Ed, in hotter climes, the fiberglass shingles are lasting longer than the organics. I've been hearing that for a few years.....and that the organics do better in cold, freezing climates. So far this is anecdotal and from sites like Bob Vila's, etc. Haven't checked for 1-2 years on this though.

As I said before some organics are not lasting like they used to here......and this is a cool climate...overnight temps here 61* F; tomorrow high 72*F...highest this summer in Halifax was 86 for a couple of days.....not near the heat that roofs get from the Carolinas down. Damn, shingles should only last a few years there.

My organics have lasted 20 years; were manufactured in 1987 so it may not be a post 70's thing but brand related.

back to the venting: that last picture shows that the vented and unvented shingles show no obvious difference in deterioration. Look at the organics on either side of the vented/unvented line- no difference.......same with the fiberglass- no readily obvious difference. What is that picture telling us?

[Ed Fako]

Brian, the following paper that I just stumbled upon is making my eyes bug out of my head at this late hour. I feel that you might be able to decipher the content at a much more functional level than I could. I glanced over the entire document, but it seems to make some points for both sides of the debate.

http://www.fsec.ucf.edu/en/publicati...6-91/index.htm

Ed

[Ed Fako]

This particular thread was so informative and full of ventilation pros and cons, I hope you all will excuse me for double psoting and bringing them to the front.

I am involved in my winter dead time research and wanted to bring this and one other post to the top.

Ed


Finally, (I am still beating my dead horse.)

By the way, I just brought this topic to the front, since I felt the report I linked was well worth viewing and saving. Ed

I have been searching for this report for eons.

Does temperature difference accelerate the aging process of composition asphalt shingles.

See page 12 of this study.

http://www.fsec.ucf.edu/en/publicati...CR-1496-05.pdf

I recommend saving this report, since the end of it, in the appendixes, has full articles of quite a few other significant pros and cons on ventilation facts and theory.

Ed

[Gregory A. Liebig]

Originally Posted by Ed Fako

...
By the way, I just brought this topic to the front, since I felt the report I linked was well worth viewing and saving. Ed
...
Ed

I just published my newsletter article yesterday regarding ice dams and sump pumps. I cannot believe all the positive feedback we've recived on my ice dam article.
I wish I was a little more forward thinking back in July regarding issues that are now happening in December in Wisconsin. Most people in our state have had problems this year due to ice dams. It's all related for us northerners. I would be happy to expound to keep this thread going. Not because of the original post, but because the better we are, the more satisfied our clients will be.

[Ed Fako]

Very well written article regarding Ice Dams and methods of prevention. It probably is the most informative article on Ice Dam prevention and alleviation I have read all in one piece.

I have many responses in a thread over at www.contractortalk.com that basically goes through all of the items you mentioned, plust a few more products with positive results.

I will see if I can dig it up, since it is only 2-4 weeks old.

Ed

[Ed Fako]

gliebig,

Here is the first 2 links to pretty decent threads about ice damming and ventilation reasons that cause them.

http://www.contractortalk.com/showthread.php?t=29431

http://www.contractortalk.com/showthread.php?t=31030

And this one is pictures of roofs with and without proper ventilation which just had 12+ inces of fresh snow fall on them the day earlier.

http://www.contractortalk.com/showthread.php?t=31798

Ed

[iniquette]

I would consider it a ventilation defect, because it's not working properly right? And nobody in Wisconsin does maint. on their house.