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-   -   Roof vents + wind + snow = Wet attic! (http://www.diychatroom.com/f9/roof-vents-wind-snow-wet-attic-59704/)

secutanudu 12-21-2009 01:14 PM

Roof vents + wind + snow = Wet attic!
 
I have some friends with a few roof vents like the one in the attached picture. We had a windy snowstorm over the weekend, and the snow blew right up into the vent and into the attic. He stuffed towels into the vent to block it for now, but what would be a good long-term solution?

It's one attic, about 1200 square feet. It has 3 vents and an exhaust fan. Is that excessive?

Thanks.

secutanudu 12-21-2009 02:39 PM

1 Attachment(s)
Forgot to post the picture...

secutanudu 12-22-2009 09:24 AM

I didn't realize there was a forum specifically for Roofing. Can a moderator please move this to that forum, or delete this one so I can re-post there? Thanks.

ccarlisle 12-22-2009 09:35 AM

Up here, we have vents that are higher off the roof just for that...its a design and code issue. Just change the vents if this is a regular problem. What's a vent? $30?

secutanudu 12-22-2009 09:45 AM

Do you have a link with a picture of those higher vents, or is there a specific name I can search on? Thanks.

ccarlisle 12-22-2009 10:06 AM

Our local Home Depot has them but I don't know about where you are. There should be a Roofing Mart or a roofing supply company that could help you there.

Ron6519 12-22-2009 10:20 AM

Quote:

Originally Posted by secutanudu (Post 370222)
I have some friends with a few roof vents like the one in the attached picture. We had a windy snowstorm over the weekend, and the snow blew right up into the vent and into the attic. He stuffed towels into the vent to block it for now, but what would be a good long-term solution?

It's one attic, about 1200 square feet. It has 3 vents and an exhaust fan. Is that excessive?

Thanks.

If your friend has a wet attic due to the snow blowing in, he has other issues as well. The attic space should be the same temps as the exterior unless there is warm air leaking in from the heated zones of the house. Unless the temps outside are lingering around the freezing mark, I'd check out the insulation condition.
Ron

secutanudu 12-22-2009 10:58 AM

The snow was piling up in their basement, then slowly melting, it wasn't immediately melting.

Won't an attic always be a little warmer than outside, even with adequate insulation under the basement floor? Or is it expected that NO heat should escape from the house into the attic?

Even so, snow blowing into the roof, even if it stayed cold up there and never melted, would still be a problem.

Ron6519 12-22-2009 01:30 PM

"The snow was piling up in their basement, then slowly melting, it wasn't immediately melting."
If the snow was getting through the attic vents and piling up in the basement, you've got problems that haven't been clearly posted.
Ron

secutanudu 12-22-2009 01:38 PM

Quote:

Originally Posted by Ron6519 (Post 370760)
"The snow was piling up in their basement, then slowly melting, it wasn't immediately melting."
If the snow was getting through the attic vents and piling up in the basement, you've got problems that haven't been clearly posted.
Ron

Whoops, I meant attic, not basement. No idea why I kept saying basement...

MJW 12-22-2009 02:42 PM

Your house will lose heat into the attic no matter what you do. It should be very close to the outside temp though.....if it is vented properly.

Now, it depends on if the snow is being sucked in or the wind caused it. If it's being sucked in (light snow fall usually) then the ventilation is too much or incorrect. If it's too warm, there isn't enough venting. If the snow is coming in just during windy snowy days, you need new vents. The ones at the big box stores are decent, but the same company (Lomanco) makes steel ones (colored) and they have a screen in them.

He could also change out the vents to the whirley bird type. When they are spinning (windy out) they don't let anything in, if installed correctly. They are a little more tricky to get set good enough to work over the normal vents.

jaros bros. 12-22-2009 06:32 PM

Good vents with spring activated dampers would solve the problem. Most of the dampers are just gravity activated and flutter all the time in the wind.

<*(((>< 12-22-2009 08:16 PM

You could also use a brillo ?sp type material that is used on metal roof ridge vents. My dad just had the same problem your friend had with blowing snow getting through the vent. It is a pourous synthetic material that looks like a brillo pad you use to wash dishes. It is made for just that application. If you can find a local roofing supply company in your area or do a search on google you will probably find what you are looking for. What this does is seal the vent from debris, however it is plenty pourous to allow adequate air exchange.

MJW 12-22-2009 09:35 PM

Quote:

Originally Posted by <*(((>< (Post 370962)
You could also use a brillo ?sp type material that is used on metal roof ridge vents. My dad just had the same problem your friend had with blowing snow getting through the vent. It is a pourous synthetic material that looks like a brillo pad you use to wash dishes. It is made for just that application. If you can find a local roofing supply company in your area or do a search on google you will probably find what you are looking for. What this does is seal the vent from debris, however it is plenty pourous to allow adequate air exchange.

That would work, but it really cuts down on ventilation, which I think the house in question has a lack of.

Just vents alone there should be 4 vents with a 10"x10" hole under them. One per 300 sq. ft. of attic floor is a good general rule.

concretemasonry 12-22-2009 10:45 PM

If the insulation is fiberglass and is wet is will hold moisture and the insulating value could be decreased dramatically. Only moving and fluffing of it in conjunction with fans and air movement has a hope of renewing the insulating properties to get back to the "advertised" values.

If it really damp or even moist, toss it out and replace with better insulation after the vent problem has been resolved.

Dick


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