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mudpaws 12-04-2010 08:54 PM

Insulating finished attic
My house is an 'expanded (Farm) ranch'- One of those type homes with an unfinished, stand-up attic reached by a fixed staircase. At least it was that way when first built. It is a gambrel (barn) roof, met on each side by opposed low-pitched gables.

Currently (not done by us) the attic is finished and very hot in the summer and pretty cold in winter. From fore to aft of the house (on each side of attic) runs two "knee wall" storage voids at the lowest slope of the gambrel roof. The rest of it is finished, heated space.

Above the living space is only the 2x6 and sheetrock ceiling before the roof sheathing/shingle. What I want to do up here is vent and barrier/insulate it properly for the best protection from the extreme heat and cold. The house has no roof vents, ridge vent, house fans, ceiling fans...nothing. I heard of those 'trays' that go between the roof rafters before insulation to promote air movement. Then again, this house has no soffits on the gambrel section, and only half soffits on the gables.

What can I do? Where do I start? I can take pictures if need be.

Immediately I am doing the garage. That roof is one of the gable sections. Soffit in front, no loft above, just the bare-raftered vaulted inside of the low-pitched roof. No overhang/eave or soffit in back.

The other gable is in two halves. That I will take photos of when we get to it.

Thanks everyone!

mudpaws 06-29-2012 03:07 PM

OK- I haven't done much in this area up until now, but I need to start getting the space ready for the kids' bedrooms. What is the best way to post photos here? I have a very hard time resizing them, so maybe photbucket or something like that? Please help if anyone can.

So, I found out a bunch of information. It was partly common sense. Talked to some people. Finally, we had some pitfalls here that ended up helping out.

In the case of trying to figure out how to cool upstairs, I realized that in a gambrel roof there really is no continuum for air movement like in a gable with soffit style. The only way I'd be able to vent this style roof is a ridge vent, and maybe some eyebrow vents on the lower rake of the barn on either side. Maybe even use power vents. When coming down from the ridge on a gambrel style roof (I was not aware of this at first), at the next point where the barn rakes down, there is a 2x-whatever that essentially closes off any air movement since it interrupts an open path for air to move. These ('blocks', if you will) connect each rafter, spanning the whole roof of the house, front to back. They make a line much like a ridge beam, at the apex of that angle on the barn roof. I'm no carpenter, so I wasn't sure before how the gambrel roof was constructed.

So, maybe I can drill little (1/2") holes in these, and use baffles (I learned that's what those "trays" are called) and power vents to move the air through and out the ridge vent?

I had a ridge vent installed when in 2010-2011 Winter, I discovered a roof leak and ice damming. Morons who used to own this house did a mint new architectural roof in 2007, and put ZERO ice and water shield anywhere. My gables that meet the lower barn rakes are a one-pitch! Absolutely would've benefitted greatly from ice and water shield.

The "half-gables"' roof sections are actually called "shed roofs". The absence of the connection "peak", "ridge", etc. at these "half-gables" create an "atrium" patio area that is enclosed by house on three sides.

OK- so finally, what I'm doing soon is this: gutting the upstairs, running wires, etc...putting in the baffles, new R21HD insulation, and those power vents if need be. Anyone have any opinions? Did I confuse anyone with the detailed explanation? Thank you all for your input and encouragement.

jklingel 06-30-2012 12:51 AM

Pics always help. Where is the R21 insulation going? Power vents are a bad idea; search here for them (and your topic, too). There are a variety of things you need to take into consideration, one of which is air sealing inside of (usually) your insulation, and venting outside it. As was recently discussed when this was asked, sometimes the best thing (though I don't love the stuff; petrochemicals....) is to spray foam the roof sheathing w/ closed cell foam. That is spendy, but it is likely the best solution for you. There is no sense in putting in something cheaper and then getting rot, so do some homework. is another place to look.

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