I have posted in the past about attic ventilation and how there are many ways to achieve good attic ventilation. Ventilation can consist of passive means that utilize soffit vents, roof vents, gable vents and ridge vents. Sometimes mechanical means are utilized with the installation of wind driven turbine type vents, and sometimes electrically or solar powered vents are installed. See these three links to past posts to learn more about roof ventilation:
When the trades don't talk to each other, @#$% happens!
What is Giovanni Venturi doing in my attic?
Not all "short-circuits" are electrical!
For my money, any time passive approaches can be utilized to do the job this should be encouraged as the use of electricity is costly.
By far the best passive approach is the use of soffit vents in conjunction with ridge vents. I have done several posts in the past regarding the Venturi effect that is created with the use of ridge vents and how this effect helps this approach be superior to roof vents and gable vents. I have also posted as to why combinations of systems are a problem.
At a recent inspection of a 5 year old townhouse, inadequate ventilation of the attic was evidenced by the beginning presence of mold or mold-like/fungal growth on the roof sheathing. Movement of air through the attic needs to be sufficient to prevent moisture laden air to stagnate where it can condense on the cold roof surface. Moisture was likely finding its way into this attic through poorly sealed ceiling fans and an attic access hatch that was not weather-stripped. The ventilation system was not adequate to keep this moisture flushed out of the attic space. Moisture laden air can also move into the attic from the exterior as well.
In this first picture one can see the darkening of the roof surface between the trusses where the mold or mold-like fungal growth is beginning to form.
The interesting thing about this structure was that provision for a ridge vent was made for installation of a ridge vent but it was never installed. Note the gap at the ridge in the next picture. The black area is the roof felt paper covering over the hole that was left for the ridge vent. At the center bottom of the picture can be seen the lone gable vent that is cut in half by the end wall framing----further compromising the effectiveness of what was already inadequate.
While most aspects of home construction are not in themselves “rocket science,” the building science aspect of the home comes pretty close. All of the trades----all of those putting the pieces together, should have proper interdisciplinary training in Building Science in order to better understand how the building works as a whole.
In this case all openings into the attic space will need to be properly sealed and/or weather-stripped, the continuous type ridge vent will need to be installed, and the gable vent will need to be removed.
Charles Buell
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Charlie,
As you know, I had three properties with similar, and way worse, attic issues in just the last couple weeks. Odd since I do not see that so often, then it was overwhelming.
President's Day, 2040
From my experience you'll be lucky if they close that gap.
Jack, are you saying I will be lucky to see is the gable vent covered up?
Steve, you are right that this one is not too bad----and it is never going to get any better without repairs.
Charles, I just came over to tell you that I loved your chocolate cake analogy on Brad's post today.....Very good, I even read it to my husband, and he also laughed.
Jane, thanks----glad I could give you a chuckle----or would that be a charle?
This post is very vivid and simple enough for me to understand! Thanks!
I wonder if this simply a case of a builder cutting corners to save a few bucks or just poor quality control. Either way, it stinks.
Barbara----did I need to talk about the electric panel too?
Jim I am sure this was about quality control. The other two unit building in the complex had the ridge vents installed.
Wow - I am so glad there are inspectors like you! :-)
Liz, it is nice to catch some things once in a while:)
I hear huff and puff and blowing houses down is good ventilation.
And I thought Ken Venturi was a great golfer too, well, in addition, apparently, to being an attic Vent(uri) specialist.
You seem to have a lot of posts lately about things growing in odd places. I was wondering why and then thought it probably wouldn't be something you would want to share...
Since that's a 5 year old home, it amazes me to see how quickly the problem can occur. I hope the owners can get the builder to correct that problem.
Good info, thanks for the lesson!
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Regina P. Brown
Jay, shall I email you privately?:)
Nancy----builder is long gone.
Regina, you are welcome.
Charlie - you always can! Too much crawl space gas making stuff grow? Radon? Well, whatever... I had a very nice house the other day and we got up into the attic to see it nearly all glowing green! Apparent mold-like, evidently-fungal, conducive-condition-to-amplify-possible fun-mold-gal substances. We all know it was mold, I just don't say it on the report. Pretty cute! Three minutes later I was not feeling well.
Nothing unusual growing yet...
Jay perhaps just too much hot (humid) air:)
I see variations of this problem quite often. I also wrote on this problem recently and in the past. It is so important that the attic be properly vented, but it seems that the tradesmen sometimes don't understand.
I completely agree with your idea of educating the people who are involved in building houses. Absolutely no training is required here in CT.
James, I should amend this story as I just got an email concerning this property saying that the roofer is willing to put on the ridge vent but is unwilling to cover the gable vent----says it would create poor venting. This is the problem in a nut-shell. What does a roofer know about building science and how venting works? Well, the answer is that they should----and usually don't. I told my buyer that I would be more than happy to discuss the matter with the roofer:)