Attic venting questions

handy man88

That's just another area in the house that will be conditioned, but will not be used. I would venture to say that your HVAC system wasn't sized to factor in this entirely new area.

Also, I would venture to say that the roof sheathing will be taking a beating.

seeyou

That's just another area in the house that will be conditioned, but will not be used. I would venture to say that your HVAC system wasn't sized to factor in this entirely new area.

That's typically not an issue. While more cubic feet of space to be conditioned is added, it's easier to condition the total space due to higher R value and less convection that results from using foam products VS fiberglass.

Gary in WA

Conditioned attics: http://www.buildingscience.com/docum...r-all-climates

http://docs.google.com/viewer?a=v&q=...GIwFLQF3YvmyFw

http://www.buildingscience.com/docum...d-roof-systems

Solar fan payback years: http://www.fsec.ucf.edu/en/publicati...SEC-GP-171-00/

http://epics.ecn.purdue.edu/hfh/_tea...larresults.htm

Dangers of powered vents; http://www.advancedenergy.org/buildi...%20Studies.pdf

Page 85: http://books.google.com/books?id=Eq1...page&q&f=false

http://www.ronhungarter.com/black_mold.html

The foam board may need to be covered: 4.2.1.2: http://building.dow.com/ee/pdf/ESR-2142.pdf

Just a few sites I found interesting. Let's keep on topic please.

Gary

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federer

thanks for the reply. i did not specifiy but in my case there is no attic actually it's completely built in as bedrooms so the space is being used completely. the ceiling of the bedroom is essentially just like 8in from the roof decking.

lemmy

Good links. But basically if you follow their recommendations then it is impossible to ventilate my roof. Not enough room for continuous ridge vents. Even if you put ridge vents on all ridges, they are at different levels so they would just short circuit each other (if you follow their logic). So you get rid of ridges and put 5-6 fans on the roof and that is dangerous and also very inefficient. My existing roof is 17 years old (with a 20year shingle) and has two powered attic fans and several short ridge vents. So my attic should be full of mold, it should be 160 degrees, everyone that ever lived in it should have died from CO and the A/C cost should be enormous. However, I see no signs of moisture or mold, and I don't think anyone has ever died in the house from CO.

handy man88

Yup. Information suffocation.

No diss on anyone, but the more you read on everyone's opinion/information on the internet, the more you head towards irrational panic.

federer

regardless I think GBR is a great resource on the forum.