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Insulating 1 1/2 story bungalow roof

Hi all,

I recently bought a "fixer upper" lake cabin. It's a 1 1/2 story bungalow from the 1920s. My first large project is going to be gutting the 2nd floor, re-roof, re-insulating, then eventually finishing off the 2nd floor again.

Anyway, the roof is framed with 2x8 rafters. I know I need to circulate air from the soffit vents to the ridge (I'm adding continuous ridge vent in the re-roof), so I was planning on the styrofoam vents under the roof deck. That doesn't leave me much room for insulation - maybe a 6" batt. The house is located in northern WI, so it will see some cold weather. I won't be there much over winter, but I would like to keep the place at 50 degrees when I'm not there and not go broke in the process. Is there anything else I can do to improve the R-value of the attic?

Thanks for the help.

Re: Insulating 1 1/2 story bungalow roof

Since you're doing the roof as well .... here's a suggestion.....

once the shingles are off and any repairs to the decking are completed ....
lay down 2 inch rigid foam over the entire deck.

Over the rigid foam lay down 2x4's on the flat .... using long screws fasten these to the rafters below.
Then apply a new roof decking to these sleepers and apply the shingles with a ridge vent at the peak.

What you end up with is the air space for the shingles .... most importantly .... you have a continious thermo break from the roof.

If you require an air space for the shingles do the above .... otherwise .... just fasten the new sheathing directly over the rigid foam.

Apply the insulation to the rafters on the inside and you have improved the performance with the thermobreak on the top side. This will improve keeping the heat out in the summer and keeping the heat in during the winter.

Just a thought. :)

Re: Insulating 1 1/2 story bungalow roof

Thanks for the suggestions. I've seen some other pictures online showing the addition of rigid insulation which seems like a good idea to get an extra R10 and have good air flow. The materials would cost me an extra $1,800, but it may be worth it. If I keep the air space above the old roof deck, I could insulate tight on the inside.

The furring strip option may also be a cheaper way to get some more insulation without spending a lot in the process.

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