DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Roofing/Siding (
-   -   sofit vents + gable end vents no ridge vent (

mattg1970 10-17-2007 06:26 PM

sofit vents + gable end vents no ridge vent
I just bought a house and I noticed that the roof has sofit vents and 2 gable end vents but no ridge vent. There is also an exhaust fan built in to the roof that is thermostatically controll. Will the sofit vents and gable end vents be enough vent this attic or should I install a ridge vent also?
Any info would really help.

Ed the Roofer 10-17-2007 08:05 PM

If your powered attic vent is still functioning, leave it alone.

By adding a ridge vent to your roof, you would further short circuit the attic ventilation.

I say further, because that is already happening with the gable vents. Close of the gable vents, if you have enough soffit intake ventilation, and then the PAV will be able to pull the fresh air from the soffits instead of the path of least resistance, being the gable vents, and completely wash through the attic.

If you desire, there are also PAV's which have a humidistat in addition to the thermostat. This way, it will turn on when the RH content becomes too saturated.

Also, there are solar powered PAV's available.


mattg1970 10-17-2007 08:28 PM

Thanks for answering my post. I do have a few questions. Living in the north east during the winter the power fan won't turn on at all because of the cold temps so how will the warmer air from the living space below the attic be vented out? Also during the warmer months what temp should I set the thermostat for the power fan for?

Ed the Roofer 10-17-2007 08:44 PM

Then if your goal is to have proper year round vwentilation, close off the gable vents and kill the power vent. Remove, patch hole, install shingles over the patched area.

Then install the ridge vent per the manufacturers specs. Many professionals prefer the Shingle Vent II by Air Vent Corp.

Go to
for other ventilation information and click on the power vents availabble and view the thermostat settings if you need to.


NateHanson 10-17-2007 08:56 PM

What's the need for ventilation if the temperature in the attic is cold during the winter? I thought the purpose for roof ventilation was to prevent heat buildup under the shingles? If it's 30 degrees inside the attic, is there any need for ventilation?

Also, I'd think that since passive soffit/ridge vents are powered by convection, then isn't there very little ventilation when the inside of the attic is as cold as the outside?

Ed the Roofer 10-18-2007 09:47 AM

The reason for winter time ventilation is to also release the contained intenal humidity.

Convection, or, the stack effect, allows the warmer moist air to rise which will draw fresher air into the intake vents to replace thecontent.

Contained humidity is moisture. Dark and warm interiors can be afeast for mold growth and the soaking of wood decking and the saturation of attic insulation.

In lieu of convection, the reason I like the Shingle Vent II and other similar knock offs, is because of the esternal wind deflecting baffle, which created negative pressure alonf the ridge line where the ridge vents are positioned and pumps out the internal moist air even without convection.


All times are GMT -5. The time now is 12:07 AM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1