Ridge vent only on highest peak or all?

Shasta

I just had my roof replaced today and was told (unless I misunderstood) that the ridge vent (Cobra II) would go along all peaks. It does run end to end on the highest peak but it's not on any of the three front and rear facing gable roofs I have. One is only a foot lower that the roof peak and covers 156 square feet. The other two are lower but cover 100 square feet each.

My house is only 1,500 square feet and I currently have 41 feet of active ridge vent. Active meaning not the asthetic part running to the end of the roof.

should I press the issue and get those gable peaks covered with ridge vent or leave it be?

My contract covered 46 feet of vent (that is probobly just the top that I got) but was verbaly told it would cover all peaks.

Thank you all!

EDITED: The power vent was removed, decked and roofed over. I now only that the ridge vent.

Ed the Roofer

http://www.airvent.com/pdf/literature/PAVbooklet.pdf

I had a very detailed response typed in place, but when I went to add this link, everything vanished.

Ed

Shasta

19 pages...Ed, I'd do much better with a paragraph or two from you. I appreciate your help and if you don't have time I understand.

Ed the Roofer

The principles of attic ventilation booklette is probably the most cited industry guide to proper attic ventilation dynamics.

You would be well served to look at the index and find the exact information for a true and accurate answer to your question. Look up "short-circuiting" the attic ventilation.

The bottom line of my previously deleted response, which included the math calculations, was that you have 46 feet of ridge ventilation at an approximate NFVA of 18 square inches per lineal foot.

Did you also have an equal amount of "Fresh Air Intake" Ventilation provided for?

A balanced flowage of attic ventilation requires between 50 % to 60 % of the total ventilation to come from the intake ventilation with the remaining coming via the attic exhaust.

The "Intake" ventilation is the more important portion of the attic ventilation equation.

If your 3 dormer roofs have enclosed attic areas which are NOT connected to the main house roof attic area or if they are drywalled to the rafters creating a vaulted/cathedral ceiling scenario, then they each must be individually vented. If the air chambers are connected, then to ventilate these lower roof attic areas would potentially "short-circuit" and compromise the entire attic ventilation flowage.

Ed

Shasta

Thank you Ed. I do have an equal and proper amount of fresh air, intake ventalation.

My concern is that 2 of the 3 dormer roofs have an area where they connect to the larger attic that is low at the threshold. This lower portion is aproximatly 3 feet lower that the peak height of the dormer attic. So, while connected, they each have higher ceiling heights but lower heights at thier connections within my attic.

In short, that hot air in those dormer sections of the attic would seem to hold heat. In the case of the largest room, it's walls are open to the east, west and south making it quite warm in these Mississippi summers.

Thank you Ed!

Ed the Roofer

Since the lower ridge lines of the dormers are at least 3 feet lower than the main house ridge line, they would theoretically act as intake vents instead of exhaust vents and thereby short-circuit the ventilation flowage.

Ed

AtlanticWBConst.

That stinks!

What is your plan for avoiding that next time?....

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Shasta

Well, I had ridge vents installed on the other three dormers today. The job is now finished. I appreciate your attempt to help Ed. To be honest, for a DYI site, your verbiage with comments like "balanced flowage" and "ventilation dynamics" would be much more suited for a professional roofing help site.

AtlanticWBConst.

No offense intended: I realize that sometimes, the information and the terms used may be overwhelming.

However, there are actually many, many DIYers with backgrounds in design or engineering (even right on this site) that eat this kind of information right up...

Ed, at times, gets into and explains the "Science" of roofing and ventilation pertaining to a particular issue. Personally, I think it's great info. and is better than providing a ''basic answer''.

I think it is similar to this: There are many chefs and cooks on TV or cable now. Some explain things simply, some get into the art and "science" of cooking.
For example; Cooking- what exactly ''happens'' when an ingredient carmalizes? Or, ''why'' you need to add a certain amount of water to a certain amount of pasta in order to cook it. Rather than just telling you to do it, without the explanations.

For every person on this DIY site that wants a simple answer, there are just as many that want to know: Why? How does it work? What is the ratio? etc, etc....

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Shasta

Exactly Atlantic! If I wrote the food channel and asked "how to make an quiche adn Alton Brown answer with egg viscosity, pepper millage and % of milk solids in chesse for the best dish, I'd had the same comments for him.

Ed the Roofer

Shasta,

All of the terms I used are included in the home owner presentation brochures put out by various ventilation product manufacturers. The concepts are very simple to understand, but a person must be dedicated to having a desire to understand prior to being compelled to investigate if things are being done correctly or not only when they are already in progress.

It should not only be your right to be well informed prior to having to have long term consequential decisions thrust upon you, but it should be expected or even demanded of each and every consumer to seek out this information beforehand.

My best clients are the most well informed consumers. They take the time to ensure that a decision which will directly influence the capabilities of the roofing materials to act as they are warranted to do, are based on facts and proven scientific studies versus some salesmans BS to just make a quick sale to an unwary consumer.

Unfortunately, until a home owner acquaints themselves with this arsenal of facts, they are just "Sheep" being herded by the unknowledgeable or unsavory contractors out there.

Too much emphasis is made on "Who will do the roof cheaper" instead of who will do the roof "The Right Way!"

Ed

P.S. A balanced ventilation scenario is listed on every manufacturers specifications and the concept of this should have been properly explained to you for you to be able to make a quality oriented decision. It is a darn shame that most 25-30 year warranted roofs only last between 12-15 years prior to being considered for replacement due to the manufacturers specifications being improperly adhered to.

AtlanticWBConst.

Ed,

As usual, very well articulated.

The points above in your quote are so, so....unbelievably true in regards to what we see property owners sometimes doing. (from an industry perspective)....

What I mean is this: (sadly) ... making a serious decision on one of the biggest investments they make in a lifetime (their home)....
simply based on going with the: ''cheapest estimate that they are able to find"....

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AtlanticWBConst.

Oops......... My apologies for hi-jacking this thread into another direction...(end of point)

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Shasta

I took the highest bid. Of four quotes, the roofer that did the work was just over $400 more than the next highest. I took that bid because they were refered. The roof is great. The mis-comunication regarding the ventilation was something that needed to be clarified but in the end, I got the best roof money and Mexican laborors can apply.

I am not sure why you assumed that I picked my roofer because he was the cheapest.

And to comment of 90% of your post. Again, the verbiage leaves me glazed eyed. Take about Charlie Brown's teacher complex. I bet your a blast when your showing vacation pictures to your friends.

but I digress. thank you both. I am done.

AtlanticWBConst.

Please bear in mind that we are on a public forum (not private Emails), thus, statements made are not always directed to the original poster of the thread, but are often directed to the general public. Sometimes, within such a posted response, there may be a simple "rant".....or.... a "general-warning" or a....."thought to consider".... which are also directed to other members (readers) here, as to "cautions to be taken".

No one ever indicated to you that you were being accused of taking the "cheapest price".

As stated, I apologized for taking the original post onto an ''unrelated tangent'' ...Honestly, the points I stated were not meant to be targeted towards you - at all.

The ('off tangent'')point was:
It's human nature to always pursue the lowest price. It's ingrained in us (myself included)....
However, when it comes to going for the "cheapest price" , the sad reality is that the cheapest price does not always = the "best deal" ...
(.....that is especially the case when it comes to getting bids to do contract work on a one's home...).

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