New Roof---Old Ventilation

Smolenski7 · 01-02-2012, 11:15 AM

I had a new roof put on my house just over a year ago. During that time, the roofer also installed a ridge cap. I have not had any problems with anything at all.

I was watching an episode of "Ask This Old House" during which Tommy Silva, the GC, said that when a ridge cap is added to a house to improve ventilation, the old side vents located near the gable on both sides of my house, should be covered because they interfere with the ventilation. Basically, they draw air from the wrong part of the house, not from under the soffits. I guess it's not as efficient.

Any thoughts on this?

joecaption · 01-02-2012, 11:23 AM

That's correct, the gable vents need to be covered up. You do have soffet vents right?

titanoman · 01-02-2012, 12:27 PM

Quote:

Originally Posted by joecaption

That's correct, the gable vents need to be covered up. You do have soffet vents right?

I got my butt chewed up and down by everybody when I suggested this in another thread .

Sent from a Samsung Galaxy S2

Smolenski7 · 01-02-2012, 12:27 PM

Quote:

Originally Posted by joecaption

That's correct, the gable vents need to be covered up. You do have soffet vents right?

Yes, I have soffit vents on both the front and back of the house.

What's the best method to use to cover the gable vents?

I was thinking some basic weather stripping around the vent and then plywood cut to size.

dmc@RCR · 01-02-2012, 01:10 PM

[QUOTE Basically, they draw air from the wrong part of the house, not from under the soffits. I guess it's not as efficient.][/QUOTE]

That is a very simple answer to a complex question. I suggest leaving the gable vents open.
There is more information on attic ventilation here.

Smolenski7 · 01-02-2012, 02:30 PM

Quote:

Originally Posted by dmc@RCR

[QUOTE Basically, they draw air from the wrong part of the house, not from under the soffits. I guess it's not as efficient.]

That is a very simple answer to a complex question. I suggest leaving the gable vents open.
There is more information on attic ventilation here.[/quote]

Thanks, but there seems to be a lot more information out there supporting that I should close up that gable vent. The video on this web site is interesting, but doesn't seem to be very scientific. It doesn't take into account many of the factors that I read about on several other websites.

dmc@RCR · 01-02-2012, 07:35 PM

Your welcome.

I know it goes against the grain. If you actually look for any "scientific" ie case studies, mathematical or aerodynamic etc., you will not find any that support closing the gable vents.

Good Luck

**Gary in WA** · 01-02-2012, 08:26 PM

I researched this quite a bit before and came to the same conclusion as this: http://en.allexperts.com/q/Roofing-1...able-Vents.htm

Here’s a good one I saved: Start reading 2 pages back and see the required size needed; http://books.google.com/books?id=Z8a...0vents&f=false

Gary

MJW · 01-02-2012, 08:40 PM

Quote:

Originally Posted by GBR in WA

I researched this quite a bit before and came to the same conclusion as this: http://en.allexperts.com/q/Roofing-1...able-Vents.htm

Gary

You sure you agree with that Gary? The guy makes some good points but then says "The more attic vents you have for the air to flow out, the better your ventilation will be." That's just not true. It is only part of the truth.

The fact is that your intake of fresh air will be the same or more than the exhaust, if the air sealing and insulation is adequate.

If gable vents are left with roof vents or a ridge vent, they may act as an intake and not draw enough air from the soffits to keep the lower area of the roof cool.

Same problems occur with too many roof vents or a ridge vent and no soffit intake. Air will go in and out in a loop pattern only drying out the top few feet of attic space.

The article's argument about the system not working in the real world is not quite accurate. It's a passive system within itself and will work no matter what the inside or outside environment is,,,,,but will not always work exactly the same with different environmental conditions.

Gary, if I missed something, feel free to point it out.

To the OP, your Roofer is correct. Seal off those gable vents.

MJW · 01-02-2012, 08:42 PM

This is also inaccurate from the article.....

For maximum benefit, the opening that the roofer cuts in the sheathing, along the ridge, needs to be as wide as possible

That is simply not true.

chb70 · 01-02-2012, 08:50 PM

I would also suggest sealing off the gable vents.

Just to make sure, if you have wood soffits with vents you are ok, if you have aluminum or vinyl soffit installed over old wood soffit you will need to make sure you actually have proper soffit ventilation.

Most of the homes that have cross ventilation that I have worked on were older homes that never had soffit vents. Just make sure.

Complete Roof

**Gary in WA** · 01-02-2012, 11:47 PM

No, I agreed with his answer to the question at hand--- "I was watching an episode of "Ask This Old House" during which Tommy Silva, the GC, said that when a ridge cap is added to a house to improve ventilation, the old side vents located near the gable on both sides of my house, should be covered because they interfere with the ventilation. Basically, they draw air from the wrong part of the house, not from under the soffits. I guess it's not as efficient.

Any thoughts on this?" --------- I think vents (above the 3' minimum) over the soffit vents would always exhaust. Unless the wind was blowing directly in a gable or static vent, it would exhaust because of the hot air rising- stack effect, mechanical or natural. Need to send BSC or someone after this for test results......Lol. I'd better read it again.....Thanks!

Gary