# Attic ventillation



## POLARBEAR (May 13, 2002)

I have a 900 sq ft house. Tall hip roof. There is almost 8' to the ridge. There are no soffit vents and the roof has 4 cans on it. 

here is a pic of the attic









Here is the inside of the roof









Here is the existing insulation.









I have removed all the planks and debris. I plan to blow in insulation and I am going to put a floor in, knee walls and ceiling for cold storage. I plan on the room area to be painted and sealed from dust and debris. At $7 a sheet, 1/2 osb is cheap and will do just fine. 

How can I get proper ventillation? Will 3" round vents cut in the soffit between every rafter suffice? Would ridge vent do better than the cans? The ridge is about 11' long. Do I need to consider power vents?


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## Bonz 54 (Apr 17, 2005)

Hey PB,

I'm not a licensed Builder, but I have done ALL the renovations to my house. I was a carpenter for years, but that was another lifetime ago. What I would do would be to add afew more cans, since you already have some you might as well stick with them. I would cut in a soffit vent at each cavity. While you're up there you might consider checking out that electrical. You could also add a Thermostatically controlled Gable Fan. They aren't very expensive and are quite easy to install. Just my .02. FRANK


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## plugger (Aug 8, 2001)

If you want to talk insulation pm splitshot. Ray is the guy for that!


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## POLARBEAR (May 13, 2002)

thanks so far. I was hoping Ray would see this post and reply. I am not going to have a "green home" or super energy efficient but I would like to be better off without to much expense. 

In this house there is sawdust in the walls for insulation and plaster walls in most rooms as well as second covered ceilings (1/2" drywall over plaster). Atleast 30" of crawlspace as well. Not at all energy efficient. lol


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## Craig M (May 17, 2000)

Hey Polar, Another option - In my old house I had the issue, no ventalation so I put in a couple of those decorative wall vents.


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## ESOX (Nov 20, 2000)

Idealy you should have continous soffit venting. I would remove the wood soffit and install perforated vinyl soffit. Another option would be a ventilated drip edge, but that is best done in conjunction with a new roof. I see you do have a section of horizontal ridge, I would install ridge vent on there and add as many louvers as needed to bring your exhaust vent side up to 1 sq foot of exhaust vent per every 150 sq feet of attic floor area. Don't forget to add the baffles before blowing in the new insulation to keep the soffit vents clear of insulation.


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## Greenbush future (Sep 8, 2005)

ESOX said:


> Idealy you should have continous soffit venting. I would remove the wood soffit and install perforated vinyl soffit. Another option would be a ventilated drip edge, but that is best done in conjunction with a new roof. I see you do have a section of horizontal ridge, I would install ridge vent on there and add as many louvers as needed to bring your exhaust vent side up to 1 sq foot of exhaust vent per every 150 sq feet of attic floor area. Don't forget to add the baffles before blowing in the new insulation to keep the soffit vents clear of insulation.


 
I installed the vented drip edge when "Perter the great" on this site did my roof. It works fine. I also got rid of the cans and did ridge vent, covered the gable end vent and blew 10 inches of new insulation. I dont see how you will put any type of floor down based on the pictures shown?? my attic floor beams are buryed in 10 inches of isulation. Cant even see em.


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## HunterZ (Jan 1, 2005)

Please do not mix your exhaust vents as previously recommended. The air flow NEEDS to come in low at your soffits and exhaust as high as possible. By mixing exhaust vents you are asking for the can style vent to be the intake for the ridge vent (both exhaust), thus sufficating the lower portion of the roof and possibley pulling in weather you do not want in your attic.


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## HemlockNailer (Dec 22, 2000)

Polarbear that roof looks like a pretty steep pitch and the vents are improperly installed. They should have been framed out so the roof boards have support on all sides. Any weight applied on the unsupported end could result in a nasty fall. I don't know how much experience you have in construction but you may want to hire a contractor to be safe.


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## ESOX (Nov 20, 2000)

HemlockNailer said:


> Polarbear that roof looks like a pretty steep pitch and the vents are improperly installed. They should have been framed out so the roof boards have support on all sides. Any weight applied on the unsupported end could result in a nasty fall. I don't know how much experience you have in construction but you may want to hire a contractor to be safe.


Dang, good eye, I didn't notice that one.
As far as mixing ridge vents and louvers, The ridge on hip roofs is not long enough to provide adequate outlet. If the louvers are kept as high on the roof as possible, just below the ridge line, with continuous soffit ventilation on 4 sides you will always have a high pressure side, regardless of wind direction, so the odds of a backdraft are very slim. On a gable roof with soffit ventilation on only two sides, I would never mix vent types.


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## HunterZ (Jan 1, 2005)

The static vent will become intake for a good (Externailly baffled) ridge vent. The"inside the pressure zone" works for mixing intake NOT exhaust.
If you have not checked you PM's, I left you the math involved.


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## Splitshot (Nov 30, 2000)

Darrin.

Did you get my PM?


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## POLARBEAR (May 13, 2002)

Thanks for all the info and pm's. I am going to take a pic of the soffit and measure the over hang and post it. Some of the suggestions here have been for a gable type roof. I have a hip roof. 

I have a good idea about ventilating it. But I wanted to get some fresh thoughts about it and see if anyone will come up with better plans than mine. lol..Simpler or cheaper. 

I did notice the cans did not have any backing to them. As you can see in the pics when I removed the chimney I used 2x4 backing there. I had thought about backing the cans but forgot. I plan on it now. Thanks for bringing that up. The pitch of the roof is tall enough that I cannot get on it very comfortably at all. So I am trying to accomplish all I can from inside the attic before I get my room built. It got a little warm up there today. So friday I am going fishing in the am then I will get up in the attic after 5 or 6pm. Have a good one.


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## TONGA (Jul 22, 2002)

Bonz 54 wrote


> could also add a Thermostatically controlled Gable Fan. They aren't very expensive and are quite easy to install. Just my .02. FRANK


They also make one that is a can style that will mount much like your vents.


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