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adebiase
Attic insulation and air flow

Hello,
I have a 100 year old victorian house with an unfinished not insulated attic. We just remade the roof and I was thinking to go ahead and finish the attic to get a 3rd room (or loft).
I am a handy person but i have never dealt with insulation hence my question.
I would like to use rolls of fiberglass between the rafters and from what i read I need to add vent buffles however neither the soffit nor the ridge have vents to best of my knowledge. It's a pretty sealed attic and is quite dry in there. If i go ahead with insulation do i still need to add vent baffles underneath it?
thank you

von_steuben
Re: Attic insulation and air flow

Yes, it's my understanding that vent baffles/soffit chutes are required for several reasons; one is to remove the heat & moisture from the underside of the roof deck by having air intake vents at the base of the roof at the soffits, and air exhaust vents at the peak of the roof (ridge vent) to expel the hot air & moisture.

This would mean, in your case, installing both the ridge vent, which is relatively easy at the roof peak, and soffit vents at the base of the rafter bays by cutting holes at the exterior base of the roof from the outside, and installing the small aluminum soffit vents---sometimes long strips of aluminum soffit vents are installed, instead of individual, smaller vents; once this phase of the project is done, you can re-install any fiberglass insulation blankets over the vent baffles & finish the new ceiling with sheetrock, mud & paint.

My own experience in doing these jobs is that they went quickly, especially the roof ridge part; but since you have an older, larger house with a roof that is probably high off the ground, it may be best to consider hiring a roofer to do this work due to the ever-present danger of falling; the site below has images of vent baffles/soffit chutes, with details about how they work to take in cool outside air at the soffits, cool the underside of the roof deck, & expel the hot, moist air out the ridge vent---this process is of course essential to keeping the new finished attic cool and livable, especially during the hot months of summer; click onto each individual image at the site below to get a larger, more readable image.

Take the time to view all or most of the images---they illustrate a lot of innovative ideas and tips on how the job can be done in different ways, and also have tips on installing the ridge vent & other roof components----ALWAYS WEAR A DUST MASK WHEN YOU GO UP INTO AN ATTIC; even the slightest disruption of the existing insulation will result in you inhaling the insulation dust particles that could very well result in your developing breathing problems, often years into the future; these type of lung problems, once they develop, are usually irreversible and are completely avoidable by simply wearing a 10 cent dust mask.

http://www.google.com/search?q=roof+vent+baffles+images&h|=en&noj=1&tbm=isch&tbo=u&source=univ&sa=X&ei=V_cUUo3bO_KAZQWR2|DoCQ&ved=OCCsQsAQ&biw=1024&bih=753

dj1
Re: Attic insulation and air flow

I second that.

Except, I don't know where to find 10 cent dust masks.

adebiase
Re: Attic insulation and air flow

thank you for your feedback.
Now, I know that cutting corners is not a great idea but here is my question. Do i really have to make vents in the soffit and ridge or i can just add the baffle vents behind the insulation? see my point? the fact is that adding soffit vents and ridge vent is a lot more work and i would need to hire someone.

HoustonRemodeler
Re: Attic insulation and air flow

Time to hire someone then.

Ridge and eave vents are the way to go.

von_steuben
Re: Attic insulation and air flow

I completely agree with Houston.

As noted previously, it's imperative that you get good air circulation using the baffles, soffit vents & ridge vent, otherwise you'll spend a lot of money & effort & wind up with a very hot, unlivable attic loft; images #19, #34, #49 & #51 clearly illustrate this---it'll be a lot more expensive to do it the wrong way & then have to go back to do it over to correct your mistakes.

adebiase
Re: Attic insulation and air flow

Sounds good. Thank you all.

adebiase
Re: Attic insulation and air flow

What about no vents and no fiber glass but polyurethane foam which seems to be also a vapor barrier? is this s viable solution?

Mastercarpentry
Re: Attic insulation and air flow
adebiase wrote:

What about no vents and no fiber glass but polyurethane foam which seems to be also a vapor barrier? is this s viable solution?

No ventilation = yes you will have problems. You need to stop trying to find an easy way out and get someone on site who is knowledgeable in this matter to recommend your best solution. There are several ways to do things that will be acceptable but having no attic ventilation is never acceptable.

Phil

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