# Ridge and Gable Vents....



## BlairHunt (May 10, 2012)

My roof has been redone before I moved in and the new roof was done with a ridge vent and the old gable vents were left. I had to install baffles to keep the insulation from blocking the soffit space on one side of the roof. Unfortunately the other side has blocking between all rafter/truss spaces. 


Is my roof vented properly? How can I figure if it is?is not?


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## BrandRoof (Dec 13, 2011)

You should close the gables for the ridge vent to work to your benifit. If not, the ridge will be counter productive. Good job on baffles, some folks are just too lazy to get up there and put them in.


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## Grumpy (Oct 29, 2008)

The fact that you can only open one side of the soffit is a problem. It means the ridge vent is really only venting half your house.

Normally I would agree with brand, cover the gables and call it done, however since there is an intake issue it's not so cut and dry. On one side of your roof, where the soffit is blocked, consider the installation of an intake vent. There are numerous, but you're going to have to install something behind the blocking. Look at smart vent or edge vent. 

If not then I would say remove the roof vent and utilize the original gable vent system, perhaps place a fan on one of the gable vents.


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## LCG (May 30, 2011)

Another point of view.

As a roofing contractor who is also an AHIT certifed home inspector there are only a few questions you should be asking. With this being an older home the following signs should tell you the truth about your ventilation issue.

#1 Are there signs of condensation or fungus along the eves of the home viewed from the inside of your attic? This will appear as effloresence (i.e white moisture stains). White moisture stains are typically caused by ice damming which may not be an issue in your area, idk. 

Fungus is fungus and is pretty easy to locate. With that said, fungus can also look like smoke haze on the underside of your sheathing. Fungus is caused by the prolonged existance of moisuture. Typically this is caused by under insulating homes. The heat rising through the attic insulation is meeting the underside of the roof decking causing moisture to accumulate. This is where the baffles come into play. If a home is properly insulated the heat does not transfer at a fast enough rate to create condensation.

#2 Heat warp? This will also look like smoke haze from the under side of your sheathing. Sometime's heat warp will actually WARP the boards or it will simply look like smoke.

Honestly most home's have sufficent ventilation with just gable vents. If neither of these issues exist then your home is most likely properly ventilated. Don't over think it or over do it. 

Another thing to look for (So much for not overthinking!) are replaced boards at the eves of the home. If boards have been replaced with the last roofing project than it is possible that there were previous condensation issues.

Make sure all of your bathroom and kitchen exhaust fans are vented to the exterior of the home. Seems basic but you would be supprised how many homes I see this in. 

In the early 70's to mid 80's builders didn't address ventilation issues. They built everything on a 4/12 pitch over a 40' span. This did not allow for proper air movement nor did it have enough air volume to dissipate any condensation that may have occured. The moisture never could get out. I have called for entire roofs to be removed, remediated, re-decked, and roofed for this very reason (mold). If your home has a 6/12 pitch or greater or has a span of more than 40' the less need you will have for additional ventilation. I know i'll catch hell for saying this but it's true. More air volume = more likelyhood of condensation dissipating naturally. Granted a little air movement never hurt anything! 

Damn it. Here I go again... The rule of thumb:thumbup: The interior of your attic and crawlspaces should be the same ambient temperature as the outside air. I would also add +or- 10 degrees. If this is achieved than you have adequate ventilation.

Leave the ridge vent. Its not affecting the gable vents. Sure its not really doing much for ventilation but it's not exactly hurting anything. No need to climb up there just to break your neck. Thats if the ventilation is fine. If not than soffit and ridge vent that sucker. 

Thats my 28 cents. Do with it what you will. Sorry for the long thread.:laughing:


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