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-   -   Failed inspection (http://www.diychatroom.com/f9/failed-inspection-75197/)

turbomangt 07-02-2010 08:31 AM

Failed inspection
 
I hired a home inspector to get an opinion on my ridge vent problem here is what he found.
My attic he says is around 1800-2000 SQ with 10 foot ceilings, an attic of that size cannot use ridge vents itís too big.
Also he found some of the vents along the soffits were not perforated, (I thought they would come from the factory with holes in the vents,)
He suggest installing 2 attic fans
What do you guys think?

racebum 07-02-2010 06:31 PM

the guys who are really up on this are going to want to know

1. what the ridge vent problem was
2. what kind of ridge vent it is
3. how long your ridge is for the quoted sq/ft

turbomangt 07-02-2010 08:51 PM

We had to go in the attic a month ago and the day was mild, 72* and we noticed how hot the attic was, so I bought a remote access thermometer and started logging the temps daily morning afternoon and night, on hot days the attic was 25* hotter in the a.m., up to 45* hotter in the afternoons, highest temp logged was 139*.
the brand is Cobra
The ridge vent runs the entire peak of the roof.

jogr 07-03-2010 12:04 AM

Your inspector is nuts. A cobra ridge vent will work fine running the length of a gable roofed house. Chances are you have an installation problem with either too small of a slot at the ridge, felt blocking the vent or a problem with the soffit vents - either blocked by insulation or not enough of the vented soffits. My bet is on insulation blocking the soffit vent air from flowing between the rafters.

Tell us the length of the ridge vent in feet.

RidgelineRoof 07-03-2010 12:22 AM

Home inspector is incorrect. That is not "too large" of an attic for ridge vent.

Slyfox 07-03-2010 05:36 AM

Quote:

Originally Posted by RidgelineRoof (Post 464657)
Home inspector is incorrect. That is not "too large" of an attic for ridge vent.

If the roof is a gable roof style I would say the inspector was wrong in his statement also, but, if it's a hipped roof and there's only 2, 3, 8, what ever feet of ridge than the inspector very well could be correct.

By far the majority of inspectors I have met are, jack of all trades & master of none persons, so find a local roofer willing to give you a free estimate on correcting your ventilation situation.

turbomangt 07-03-2010 08:14 AM

Is anyone on the forum near chicago? the length of the main ridge on peak of house is appx 65 feet, Gary

RemodelMan 07-03-2010 08:27 AM

ridge vent
 
Regardless, I'd invest in a large power vent with a built-in thermometer trip switch. Make sure it is located on the cool/North side of the roof/peak or which ever has the most shade. But like jogr stated, check for insulation stuffed up too tight to the ridge.

racebum 07-03-2010 01:43 PM

65 feet of ridgevent on 2000sq ft? holy hannah, it should have no problem at all. the above post on intake airflow was also my guess. either not enough intake, blocked vents due to blow in insulation going everywhere or a mis-installed ridge vent.

Gary in WA 07-03-2010 06:55 PM

Intakes are blocked: http://www.fureyco.com/content/image...ng_The_Air.pdf

The math- 150 min. or 300 min. with v.b.: http://www.airvent.com/homeowner/pro...it-specs.shtml

The intakes are way undersized if not continuous or minimum of 9 NFVA per foot: http://www.lomanco.com/intakemain.html

Interesting reads: http://www.advancedenergy.org/buildi...%20Studies.pdf

http://www.ronhungarter.com/black_mold.html

http://www.blocktheheat.com/ventproblems.htm

Be safe, Gary

jogr 07-05-2010 10:33 PM

65 feet of ridge vent is plenty if the slot is cut wide enough and not blocked with roofing felt or shingles. When you are up in the attic can you see the size of the slot and verify it's not blocked?

Can you see how much of the soffit is perforated and see if the soffit vent airflow is blocked? Do you have soffit vent chutes to keep insulation from blocking the vents?

DO NOT INSTALL POWER VENTS OR OTHER ROOF VENTS. They will ruin the effect of the soffit/ridge vent combination and cost needless money. What you have should work but it might need some blockage removal.

johnk 07-05-2010 10:38 PM

Grumpy and Ed the roofer are in the Chicago area.

Michael Thomas 07-06-2010 05:49 AM

Quote:

Originally Posted by turbomangt (Post 464699)
Is anyone on the forum near chicago? the length of the main ridge on peak of house is appx 65 feet, Gary

I'm here as well.

The first thing we need to know is: "What is the "problem" you are trying to "solve"?

As Ed notes, the venting potential of ridge vents (and lower venting such as soffit vents as well) depends a good deal on roof configuration, it's not possible to have an informed opinion without seeing at least pictures of the roof/attic.

One concern I have is that if the recommendation for "2 attic fans" was for powered roof ventilation (fans drawing air from the attic and exhausting it to the exterior through the roof) it's unlikely a typical unmodified 2000 ft/2 attic provides sufficient make-up air for even one.

If not, you are going to be depressurizing the attic. In which case when the fan(s) are running the pressure differential (added to the inherent stack effect) will be drawing (perhaps a lot of) conditioned air from the spaces below into the attic, and worst case could be causing back-drafting of gas appliances in conditioned spaces.

It's *really* hard to find roofers, home inspectors or anyone else who really understands this stuff because there are so many variables: roof design, roof coverings, ventilation and insulation and vapor retarders/barriers (at a minimum) are all involved, and IMO except in the case of the simplest open attics under gable or hip roofs specification of solutions to such problems is a bit of a black art - you start by trying the simplest and least expensive solutions (that you believe won't make things worse) first, and then proceed on from there.

turbomangt 07-06-2010 07:57 AM

Tell me this, on a bright sunny day, if you go into your attic, turn off the lights, and see some day light being reflected in from your ridge vent, should this light be continuous throughout the entire length of the ridge? when I go up there I see some light here and there but certainly not consistent the with the whole length of the ridge which leads me to beleve the opening was not cut wide enough for the entire path,
Michael, the problem I'm trying to solve is if I have a properly installed ridge vent and eve vents to achieve the right air flow.

Michael Thomas 07-06-2010 09:48 AM

Quote:

Originally Posted by turbomangt (Post 465893)
Tell me this, on a bright sunny day, if you go into your attic, turn off the lights, and see some day light being reflected in from your ridge vent, should this light be continuous throughout the entire length of the ridge? when I go up there I see some light here and there but certainly not consistent the with the whole length of the ridge which leads me to beleve the opening was not cut wide enough for the entire path,

There is a good chance the vent was over-nailed and the vent fabric (the "scrubby-like material" inside the vent) is compressed in places.

Quote:

Originally Posted by turbomangt (Post 465893)
Michael, the problem I'm trying to solve is if I have a properly installed ridge vent and eve vents to achieve the right air flow.

The "right airflow" within an attic is the airflow that prevents undesirable results, for example moisture levels that promote mold growth, or "ice damning."

If the current attic ventilation is not creating problems or failing to solve them, then question then becomes: "Why change things?"

This is not a theoretical question - for example I just inspected a large turn-of-the-century three story Victorian home in Evanston that had *no* attic ventilation... and more than a hundred years later. no signs of problems as a result!

This is an extreme example, and I'm certainly not recommending that people build unconditioned attics with no ventilation.

But in the case of this Victorian while you can report that the ventilation is (radically) sub-optimal by current standards, you also have to ask yourself "What is the functional defect?

Which is why I am asking, "What is the functional problem you are trying to correct?"


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