Thoughts on GAF Cobra IntakePro rooftop intake vent

Looking for any input here, hopefully someone with experience working with this product, does it produce adequate air flow intake to attic?

I have 2 layer shingled 2,500 sq ft of roof over my ranch that needs to be redone. Had 3 contractors come out to estimate, and only the last one pointed out that there is not intake on the back of the house, and the soffits on the front are blocked by plywood for who knows what reason. I currently have two gable vents, but every contractor told me they would add a ridge vent. Only this last guy said I needed proper intake ventilation, and could do so with the Cobra Intake Pro. Didn’t see a lot of information online except what had been written by GAF themselves. I found some reviews on Home Depot but pretty scatter shot and not instilling confidence. House was built in 1981, coastal NJ.

http://m.homedepot.com/p/reviews/Cobra-10-1-2-in-x-20-ft-Ridge-Low-Profile-Exhaust-Vent-in-Black/100000023/1?sort=Oldest&reviewsRating=0

It is better to use the soffit for intake if possible, the plywood you speak of can probably be removed and in either case you still need to have rafter baffles in place or installed.

I have never used the Cobra intake product and never will due to the way it is made but there are better alternatives like Smartvent or the Edge vent, these do the exact same thing with better material & design.

If you currently have no intakes you likely need to have rafter vents installed also.

Again, it is better to vent through the soffit when possible and only use these surface mounted intakes when other options are not available or possible.

Venting through the soffit will likely require more work and expense, as usual something better costs more…

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Thank you, that is good perspective. Do you have any idea why soffits would be installed on the eaves but then appear to be blocked? I haven’t had the chance to crawl up into my attic and pull the insulation back yet, but is there some technique/product that sits on top of the soffit on the inside, and maybe it just appears to be blocked but it’s really some baffle type cover between the insulation and the soffit?

Older homes weren’t usually built with ventilation in mind.

Soffits aren’t “installed on the eaves” they are a part of the roof and truss/rafter system, it is the overhang at the eaves.

If you don’t have an overhang at the eaves you will need to go with the surface mounted intakes.

For airflow there need to be baffles keeping the insulation from blocking airflow from the eave to the ridge.

On some older homes there is not enough heel height at the wall line to install baffles and have adequate insulation, in these cases a cold roof is ideal.

When we install baffles we remove the first course of sheeting or enough planks to access the lower portion of the roof, insulation frequently needs to be added at this point.

There are few different ways to install intakes under the soffit once the baffles are in place depending on the construction of your particular soffits.

One thing about these surface mounted intake vents is that if they are put farther up the roof they become prone to being smothered by snow and can become overwhelmed and encased in ice.

Perhaps you should meet with one of your local roofers and have them explain this to you while pointing out what exactly they are talking about.

Ventilation isn’t an exact science and each building needs it’s own solution.

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While 99% of the contractors you talk to are going to recommend soffit vents
Some very smart people will tell you otherwise. Joseph Lstribruek of building science is one of the foremost authorities on the subject.
Having soffit vents actually can cause ice dams and blocking off soffit vents and using fascia or soffit vents is the best choice to prevent ice dams

"Having soffit vents actually can cause ice dams and blocking off soffit vents and using fascia or soffit vents is the best choice to prevent ice dams"

Can you clarify this statement as it appears contradictory.

Ventilation isn’t an exact science and each building needs it’s own solution!! Thank you! Now if anyone will accept that premise…

Go into the attic on a sunny day and you’ll see light at the eaves if it’s vented. Smoke bombs work, too.