Cobra ridge vent problems

**Ed the Roofer** · 06-26-2008, 03:27 PM

That one sucks if you have gutters OR get snow and ice in the winter.

Ed

**Ed the Roofer** · 06-27-2008, 01:49 AM

Quote:

Originally Posted by dharris008

The simplest type would be the round "Plug" vents. All you need to install these is a drill and the proper size hole saw. 4" work better but multiple 2" will also work.

With the Ridge Vent providing 18 square inches of NFVA per lineal foot, you would havwe to match or exceed that quantity from the Intake Vents you use.

A 2 1/4 inch diameter provides only 1.50 square inches per vent plug

A 4 1/2 inch diameter provides only 3.00 square inches per lineal foot.

You would need to install 3 of the 4 1/2 inch diameter plugs every lineal foot of the soffit on both sides of the roof to only equal the amount of the Exhaust NFVA.

What wrong with that picture?

3 x 4 1/2 inches = 13 1/2 inches, plus, that would require them to be one hole right next to each other and you would never get enough in place.

Those specs are from the C-Series Under Eave Cornice Vents, also known as Mini-Louver Vents, from Lomanco.

www.lomanco.com/ProductPAGES/CirkVents.html

dharris008 · 06-27-2008, 08:28 AM

I understand that plug vents or drip vent may not be the ideal type of ventilation but it is better than doing nothing. As he stated in his previous thread, he only has a small amount of eave and wasn't considering adding eaves to the house. A combination of, simple to install, vents is still better than doing nothing. What would you suggest that is very cost efficient and he will be able to do?

**Ed the Roofer** · 06-27-2008, 09:38 AM

Sorry that I did not expand on that last night.

The most practical product to use for continuous Fresh Air Intake Ventilation, is the Smart Vent, by DCI Products Inc.

It is a tapered, shingle over style product which lays on top of the decking, where a 1" slot has been cut out of the decking at the 6" to 7" point from the eave, which then align with the gap in the product, which then allows fresh air to be drawn through the capillary tubes of the coroplast material and then enters into the attic environment.

This provides 9 square inches per foot and when both sides of the house are done with it, then there is an exact balance between intake and exhaust.

An additional plus, is that it will not get clogged from dust and insulation in the attic and will never get painted shut, diminishing its ventilation capacity for intake.

Do a search for Smart Vent on this forum by my User Name. I have been using it for years.

Ed

the roofing god · 06-29-2008, 12:48 AM

check out "the edge" by Airvent

4just1don · 06-29-2008, 09:51 PM

so with the ridge vents and those smart vents or similiar,,,do I close OFF and not use the end gable vents??

Other question,,,how reliable is that flap closing on the cor-a-vent X5 vent?? Do they last as long as a roof?? AND what kind of shingles work these days?? HERE fiberglass shingles dont seal and tend to blow off,,,was told 100 miles south of here they work,here NOT!! Always did the white asphalt in old days,,,was thinking of going with darker color in a asphalt shake kind. Looks good and supposed to LAST longer.(thicker) and heavier

What say you pro roofers??

rh55 · 03-28-2009, 10:29 PM

We've got a bunch of leaves in our attic, primarily in the section over the garage. Roof was installed in 2004 using Cobra Rigid Vent II ridge vent. The leaves are small oak leaves (Texas red oaks). I was skeptical this was how they were getting in until yesterday.

We had a bad hail storm that left a lot of leaves, twigs, and branches (and one dead bird) on my roof. While sweeping the roof, I found a lot of leaves half in to the grate holes (rectangular) in the ridge vents. The wind here is predominantly North-South, and the roof and ridge vent are East-West, so the leaves and dust get blown up the roof until they hit the ridge vent at the peak. I saw this happening as I was sweeping and stirring up dust.

When I googled for Cobra ridge vent leaves in attic, I found three other posts about this happening.

Adjuster is coming next week, and at least one of the roofers (there have been a lot) has said to expect full replacement (the ridge vent was heavily damaged by the golf ball sized hail).

Which leads to a question - what attic ventilation should I think about replacing the Cobra vents with? Ridge vents make intuitive sense to me as far as effectiveness in venting hot air, but I'd like something that will keep leaves out also.

**Ed the Roofer** · 03-29-2009, 01:19 AM

Shingle Vent II by Air Vent Corporation is by FAR the best Ridge Vent product on the market.

Ed

Diamonds07407 · 04-29-2011, 07:55 PM

Hi ed i just read one of your postings that said that you put a 1 1/14 or 1 1/6th space between the sections? I understand the concept which makes sense, but then why doesn't the company have 'instructions' on how to install these? I just saw something that said to butt them together? That contradicts what you said and what happens if you over lap each piece instead of butting them together?
Thanks

**Ed the Roofer** · 04-30-2011, 12:29 AM

The installation instructions for installing the Shingle Vent II from Air Vent Corp., do state to leave a slight gap between each section piece of ridge vent.

http://www.airvent.com/pdf/installat...II-install.pdf

SEE ITEM # 5 IN THE IMPORTANT NOTES SECTION AT THE BOTTOM.

ShingleVent II fits roofs with 3/12 to 16/12 pitches.
ShingleVent II-7 and II-9 fit roofs with 3/12 to 12/12 pitches.

1.

On existing roofs, remove cap shingles. Mark

slot width at both ends of ridge. Use slot guides

imprinted on vent and refer to drawings below.
Snap chalk line on both sides of ridge.
4.

Pre-fasten first section using roofing nails

through pre-drilled nail bosses. Continue to

pre-fasten remaining sections, making sure
support ribs are flat on the roof and filter is
secure between shingles and vent.
5.

Use utility knife to cut final section to length.

Final section should be oriented so that the integrated

end plug is flush with the end of the roof.
Pre-fasten final section.
6.

Nail cap shingles in place using roofing

nails long enough to penetrate roof sheathing.

Use nailing lines provided on vent as guide. If
using a nail gun, see #8 under important notes.
2.

Cut slot (plumb cut, if possible). Note: Adjust

depth of blade to avoid cutting rafters or trusses.

Refer to drawings below for slot dimensions.
Remove debris from slot.
3.

Center vent over slot. End should be flush

with end of roof. Make sure vent’s support ribs

sit flat on the roof, and that filter is secure
between shingles and vent.
Hip and Gable Roofs
Cut slot 3/4" on both sides of ridge centerline
or from ridge board and to within 6" of end
wall or hip intersection as illustrated in
Figure 4.
"L" and "T" Shaped Roofs
Cut slot, as per

Figure 5 and run ShingleVent II

across long ridge. On short ridge, cut slot to within

12" of junction point and run ShingleVent II from
end of roof to butt against crossing ShingleVent II.
Chimneys
Cut slots to within 12" of chimney. Run
ShingleVent II from end of roof to butt
against chimney as shown in Figure 6.
Highest quality co-polymer

remains sturdy,

nailable, and flexible, in all climates.

Cap shingles install easily

, making the vent

virtually invisible.

External wind baffle

creates low

air pressure above the vent and helps

pull air out of the attic.
Built in end plug

seals the end.

High gloss nailing lines

for accurate,

fast cap shingle nailing.

Nail bosses

, reinforced nail holes

designed to prevent over nailing,

located at 16" and 24" centers.
Air slots

have 18 sq. inches (ShingleVent II)

or 16 sq. inches (ShingleVent II-7 and

ShingleVent II-9) free vent area per
lineal foot.
I N S T R U C T I O N S F O R C U T T I N G S L O T S
4117 Pinnacle Point Drive
Suite 400, Dallas TX 75211
800-AIR-VENT (247-8368)
(See other side for additional installation instructions)
I M P O R T A N T N O T E S
1.

When using standard flat 3 tab shingles, it is unnecessary to caulk under flange of the vent.

2.

Caulk between low areas of shingle and flange of vent, making sure you don’t plug drain holes.

3.

When applying vents to shakes, fold felt as shown in drawings on other side.

4.

Before fastening vent, make sure filter is secured between shingles and vent.

5.

When installing vent in cold weather, leave a 1/8" gap between vent sections to allow for expansion in hot weather.

6.

See instructions below for cutting slot.

7.

For best appearance, run ShingleVent II from end to end to give the roof a more even, attractive appearance.

8.

When using a nail gun to install cap shingles over ShingleVent II, special care should be taken. It is important that the roofing

nails penetrate the roof deck without compressing ShingleVent II. Nails driven too deep will dimple or distort the cap shingles.

Nails not driven deep enough may allow ShingleVent II fasteners to back out of the roof deck and could result in blow-offs.

Ed

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