Attic Ventilation - Roofing/Siding - DIY Home Improvement | DIYChatroom


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Roofing/Siding

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 08-29-2012, 02:37 PM   #1
Member
 
Join Date: Jun 2010
Location: Southeastern Massachusetts
Posts: 106
Rewards Points: 75
Default

attic ventilation


Hello -

I live in a 1940s cape home in MA (see photos) and we suffer each summer on the 2nd floor, which doesn't seem to cool down on its own on cool nights. The outside air can be 65-70, but the rooms stay 75-80. I'm suspecting that hot air is trapped in the attic and is to blame. We can run window AC units but that gets to be a drag on our electric bill.

The only venting present are two 12x9" gable louvers on each end of the house. There is no ridge nor soffit venting.

I've read that ridge vents are great, but aren't as useful with the presence of gable vents. Although I don't understand this because wouldn't hot air rise and escape through the ridge vent and pull the outside air through the gable vents? I also don't want to cut an opening in my roof if I don't need to.

Or, I could forget the ridge vent and just add a powered gable fan and plenum to drive hot air out one and gable suck cooler air in through the other? Yes its extra electricity, but I'd only run it for a few hrs at night.

Any other thoughts would be appreciated. Thanks.
Attached Thumbnails
attic ventilation-house1.jpg   attic ventilation-house2.jpg  

Advertisement

debiasio is offline   Reply With Quote
Old 08-29-2012, 02:46 PM   #2
Member
 
AGWhitehouse's Avatar
 
Join Date: Jul 2011
Posts: 1,378
Rewards Points: 500
Default

attic ventilation


The ridge vent won't really work with the gable vents because there is not enough vertical distance between them. Code has a measure of 3 vertical feet between intake and exhaust before a different set of ventilation parameters are enacted. This difference in height is what makes natural thermal convection become active.

With your kind of house it would be difficult to traditionally vent the roof/attic without extensive interior work that would require close to a full gut. A powered gable vent fan on a humistat/thermostat does work, to a certain extent, and is the cheapest solution. The best solution, though no-where near cheap, is to replace your roof and provide a venting plane there. You could also insulate at the roof level while your at it and reduce the temperature swings of the upper story. You would essentially add another layer of sheating on your roof and then new shingles. This would provide and air space for heat-laden air to move. here is a generic photo of a vented roof sheathing http://www.alcespostandbeam.com/SIPs...ent_02_med.jpg

They also make insulated vented roof panels. they look like this: http://www.flickr.com/photos/hunterpanels/5654955641/ these offer the added benefit of additional insulation while provided the appropriate ventilation.

Advertisement

__________________
Life's too short...so enjoy it!
AGWhitehouse is offline   Reply With Quote
Old 08-29-2012, 04:51 PM   #3
Member
 
Join Date: Jun 2010
Location: Southeastern Massachusetts
Posts: 106
Rewards Points: 75
Default

attic ventilation


Thanks for the reply and the links. I had never seen panels like that before. Looks expensive to implement that type of ventilation, however.
debiasio is offline   Reply With Quote
Old 08-29-2012, 06:15 PM   #4
Member
 
Join Date: Jul 2010
Posts: 142
Rewards Points: 83
Default

attic ventilation


It doesn't appear you have vented soffits, am I correct?
If not, you could go with the power gable vent and I would install it on the side of your house that is in the sunlight in the afternoon/evening so It can blow hot air out and suck in cooler air from the shaded side of your house.
bcdemon is offline   Reply With Quote
Old 08-29-2012, 06:38 PM   #5
Member
 
Join Date: Jun 2010
Location: Southeastern Massachusetts
Posts: 106
Rewards Points: 75
Default

attic ventilation


That is correct. The soffits aren't vented. I was thinking the same thing you mentioned, using a powered gable fan to provide active ventilation.
debiasio is offline   Reply With Quote
Old 08-30-2012, 10:27 AM   #6
Member
 
AGWhitehouse's Avatar
 
Join Date: Jul 2011
Posts: 1,378
Rewards Points: 500
Default

attic ventilation


Quote:
Originally Posted by debiasio View Post
That is correct. The soffits aren't vented. I was thinking the same thing you mentioned, using a powered gable fan to provide active ventilation.
This is the quick/cheap method, though it's not going to solve your heat gain issues in the upper rooms. It may help slightly, but won't solve. You have alot of roof surface that is in direct contact with the rooms in question and the heat transmittance through that assembly cannot be mitigated with a fan in that tiny attic space.

Advertisement

__________________
Life's too short...so enjoy it!
AGWhitehouse is offline   Reply With Quote
The Following User Says Thank You to AGWhitehouse For This Useful Post:
Windows on Wash (08-31-2012)
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Attic ventilation tmaher HVAC 5 06-09-2011 11:54 PM
Improve attic ventilation? Greenmaze Roofing/Siding 28 07-22-2010 03:16 AM
Attic Ventilation. Just double checking before I start ... :) matjam68 Roofing/Siding 11 03-16-2010 09:38 PM
Powered Attic Fan question spup345 Roofing/Siding 9 06-30-2008 09:10 PM
Proper Attic Ventilation kmhill35 Roofing/Siding 2 04-01-2005 09:11 PM




Top of Page | View New Posts