PSA for those with Ridge Vents for their attic air-flow

3,164 Views | 5 Replies | Last: 4 yr ago by evan_aggie
91_Aggie
How long do you want to ignore this user?
AG
If you have Ridge Vents on your roof, please go check all your soffit vents (located under the eaves).

These should not be blocked, painted over, clogged with dust/dirt or covered with insulation.

And make sure your builder put enough in for attic square footage, and that they actually cut the holes big enough for each vent.

Even if you add a fan to your roof (solar or electric) or extra whirlybirds, if you don't have enough "NFA" for intake, you aren't helping much, especially if you have fans... if those fans can't pull air from those vents, they will pull them from air conditioned house (assuming you don't have a 100% sealed ceiling... which you likely don't)

My damned builder didn't put enough in and they cut the rectangles about 1-2 inches too small on every soffit vent. That reduce each vents value by 20 to 40 square inches... almost everyone was installed under a rafter further reducing that NFA.

Oh, and it took me 20 years to finally research this... so I feel dumb for not really researching it before.

Here's a calculator for you:
https://www.owenscorning.com/roofing/components/vent-calculator

And if you all knew this and are shaking your head after reading it, that's fine. Just trying to help at least one person.

(FYI, I checked my neighbors on both sides... one of them has fully closed vents that have been painted over. Don't know if they did it or original builder did, but they are not getting any airflow). Other ones had the vents open at least (not smushed down, but they are completely clogged by dust/dirt and are cut too small like mine were.)
AtlAg05
How long do you want to ignore this user?
AG
My eaves have a bunch of holes like a peg board, not sure if that is best or worst than an actual vent.
Whoop99
How long do you want to ignore this user?
AG
I've gone through this as well. I had new vent fans installed when my roof was replaced. The next day, the humidity in my house spiked to almost 80% The problem was due to the soffit vents being blocked with dust/dirt and the holes being cut too small. The vents were pulling air from inside the house to compensate. It took me a couple of hours to pull each vent cover down, hose off the cover and cut new openings where needed. As soon as I did this, the humidity problem with the new vents was fixed. Good luck!
Gig 'Em,

Whoop99
SeMgCo87
How long do you want to ignore this user?
AG
There were some builders in Houston in the 70's (Pace comes to mind) who built "Contemporary" designed houses - with no overhangs, therefore no inflow possible. The only solution I can see, without soffit venting is powered vent fans across gable roofs...of course, hip roof designs nullify that approach.

This, during a time when there was a big push for energy conservation in house design.

Go figure...
lotsofhp
How long do you want to ignore this user?
AG
There are intake vents that can be installed on the roof if you don't mind the look.



https://www.lomanco.com/vents/specialty-vents/deck-air
BrazosDog02
How long do you want to ignore this user?
AG
Ok. Here's the deal with the vents above. They work. However, several manufacturers make them. They all function the same but they all install slightly differently. We don't do a lot of these....but I like to meet with my crew to make certain everyone installing these understands how they work, how they are to be installed...including how to cut decking and lay the underlayment so it doesn't leak. It's important, but it's not hard. The directions are easy to find.

These also have pitch limitations....again....outlined by the manufacturer.

There are a lot of homes referenced above that have no soffits or eave boxes. So...you need to pay attention to where you put these. In some of these instances they work but they don't look great. I'm a function over aesthetics person myself if that's the o my option and the customer wants to pay for it.

Also, as noted, you need a clear roof deck path to the ridge for proper venting.
evan_aggie
How long do you want to ignore this user?
AG
I've probably told this story on similar threads, but damn if that'll stop me from telling it again!

My wife and I bought a 1949 craftsman style home in April 2018. I installed a bathroom exhaust vent and cut a hole in the roof. It was like someone had turned on a hair dryer through the hole I cut. I scratched my head.

I put a temperature sensor in the attic and would watch it warm in the day. Almost every day last summer it would get to 135-138F. On the worst days it would get to 145F.

We have gable vents, three of them, and I decided to install a small 1000 CFM ERV4 MasterFlow fan. Did that, and saw the temperature drop to 120-122F.
Refresh
Page 1 of 1
 
×
subscribe Verify your student status
See Subscription Benefits
Trial only available to users who have never subscribed or participated in a previous trial.