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Question DetailsAsked on 2/9/2016

Is the Lo Omni ridge vent system by Lomanco a good roof vent system?

I own a 3-story townhome with your basic metal ridge vent on an asphalt shingled roof. During the major snow storm in January 2016, the winds blew the snow into the attic through this ridge vent causing damage to the drywall on the 3rd floor. The insurance claims adjuster said the ridge vent is fine. One contractor never called me back. Two other contractors both told me the ridge vent needed to be replaced. Neither the claims adjuster nor the 2 contractors actually got up on the roof to physically inspect the ridge vent. It seems impossible to get a contractor over here to get up on the roof and take a look at it. With that said, I'm leaning toward the Lo Omni roof vent made by Lomanco. Any recommendations for this product?

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3 Answers


You are not alone in what you have experienced. I recently attended a seminar on udated venitlation options. The Company Air Vent makes a product specifically designed for your purpose. It is ridge vent that has a baffle and filter as part of the design. Many of the companies out there have issues like you described with snow coming in. But, many of them do not want to admit it.

Exterior Upgrader is owner of

Euro-Tech, Inc.

Servicing much of Illinois and Wisconsin


Answered 4 years ago by ExteriorUpgrader


All of Lomanco vents, including ridge vents, should not allow weather infiltration when properly installed. Try to determine what is causing the vents to leak...

The number one reason a vent will fail is because of lack of intake ventilation. Intake vents, installed near the soffit / overhang, are required. The ventilation system needs to be 50% intake and 50% exhaust. If your ventilation system does not have intake vents, you will need to add vents in the soffit or lower attic area. Lomanco manufactures several types of intake vents, including a roof mount intake vent, our DeckAir, model DA4. Here is a link to our intake page on the website.

Another reason a ridge vent can allow infiltration is cutting the hole too large. The size of the hole will depend on what vent you have and the type of construction. If you can see the internal baffles from the inside of the attic, your hole is too large. Please refer to the instruction sheet of the product you have used to see the prescribed hole size.

Other scenarios that can allow infiltration are mixing exhaust products and having the ridge vents at different levels. Do you have any other vents installed with the ridge vent? It is not recommended to have 2 types of exhaust vents (such as gable vents, turbines, power vents, etc). Is the ridge vent installed only at one level? If ridge vents are installed at different heights, the lower vent can act as an intake vent and allow infiltration.

Please take a look at some of the factors I addressed and let us know if you can determine what could be causing the vent to leak. We do have Area Market Managers who can get involved if the cause can not be determined.

All Lomanco Omni Series products have internal baffles. You will never see a fllter in a Lomanco vent. Fliters will become dirty and eventally clog and restrict your air flow.

Thank you,
Clayton Cavaness

If you need additional help please use the link below.

Lomanco Support

Lomanco's 3 Must Do Steps for ventilation.


Answered 4 years ago by claytonc


I have never seen it in person, but I would stay away from the Lo Omni - go this link -

and move cursor over the product picture so it blows up the view - see how you can see straight through the baffles at the right side of the roll - if you can see straight through from the edge, dry snow can blow straight through too. Also, their baffles are vertically oriented, so the air (and snow) is redirected sideways - that does not stop entry. What you need is horizontal baffling, so the snow has to go through a vertical maze and gets packed and caught - and also has to be designed so the melting snow then runs back outside, not inside.

Unfortunately, most of the manufacturers appear to not have any engineers on staff who have had a fluid dynamics course - because the correct design for a ridge vent system would be one that vents up through the center slot in the sheathing to near the top of the vent, then down to a low-lying inlet - so any snow or debris blowing in would hit baffles low down in the solid part of the vent, and could not get into the center slot without passing up several inches through baffles to the top interior area of the ridge vent. Another erro in their design is also that they are kept so thin to minimize visibility - where to work right they should be at least several inches thick. Think what worked so spelndidly in the old days - louvered cupolas several feet high as ridge vents - with a solid ridge cap oer the sheathing slot between cupolas. They vented many times more air than modern ridge vents, and were effective (when built right with internal baffles) in keeping even Great Plains blizzard condition very dry snow out from the attic.

What you need is a baffled and maybe filtered vent as the other comment said - and one specifically designed for snow conditions, like the GAF Cobra Snow Country or equal. The product itself costs quite a bit more - but total installed cost only maybe 10-15% higher.

The comments from the Lomanco rep about filters blocking up can be true in areas with a lot of windblown tree debris and such, but filtered vents work best in mkeeping snow out - you just have to get up into the attic every few to 5 years or so and blow the filter clean with compressed air, or work carefully (to avoid damaging the baffles and ribbing) from the outside with a paint brush and shop vac to pull the debris out of the screen or filter. And don't buy the argument that the filters pack with snow and stop ventilation in the attic - it is a rare house that will not heat up the attic enough to melt out any blockage in short order if the ridge vent blocks up with snow. Debris - that you still need to clean out.

Answered 4 years ago by LCD

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