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imtryingtofixit 02-27-2010 03:59 PM

sloped roof insulation
2 Attachment(s)
This is my 1st post so hope I'm in correct place. I live in sunny Alberta, Canada and own a 1915 two storey house. It is built on the idea of a barn style with an approximate 2 foot flat area at peak, then roof gradually slopes down - east, west - to meet walls. 9' ceilings on second floor. no soffits, so no soffit vents. The sloped roof is the ceiling of the bedrooms with of course the 2x4 construction gap. All inside walls, ceilings are tongue and groove shiplap? wood. Very solidly built. How do I go about insulating the "ceilings" in the bedrooms and still leave the air gab? No room for vapour barrier or the rafter air barriers that they now have. As no air enters through soffet vents now to keep roof cool will I be creating a worse situation if I have blown insulation put in these areas. Will be reroofing this spring and do not have sheeting on roof either. Should I have insulation blown in this way. Should sheeting be installed. Will be using water and ice shield on bottom portion and valleys. Should this be only place I install this. Floor in attic (undeveloped) is well insulated with blown insulation 18". Do I need roof ridge venting. Should I install whirly bird vents. Thanks for any assistance you can offer.

jeweler 03-03-2010 12:51 PM

Are you going to be doing the roofing job yourself? Either way I would have a few roofers bid the job. Find out how they would handle your issues. It will tell you much, both about the roof and about the roofers.

I'd like to offer advice, but, without pictures or drawings, your explanation is not sufficient.

jlhaslip 03-03-2010 09:58 PM

I don't think blown-in insulation works on a sloped ceiling space, but I might be wrong.

imtryingtofixit 03-04-2010 11:45 AM

Thanks for the great ideas. This should be a good way to determine a good contractor. I am also adding photos. Sorry about that.

Gary in WA 03-04-2010 12:51 PM

As jlhaslip said:
Check with your LOCAL Building Department.

Be safe, Gary

AaronB 03-04-2010 02:07 PM

If your conditioned living space is well insulated, you shuld be good to go. You should not need insulation in the roof framing unless youre trying to convert this space to conditioned space.

Ventilate it.

Install roof sheathing if youre installing a roofing system that needs it.

imtryingtofixit 03-04-2010 05:49 PM

I am not sure that I understand your advice. Or maybe its that my explanation was not clear. As noted in the photos which I have just downloaded the sloped roof is the ceiling in the bedrooms - 4 bedrooms. The roof is constructed of 2X4's, horizontal boards instead of sheeting, asphalt shingles. In some areas the boards leave numerous inches between each meaning that the shingles are the only thing between attic and the great outdoors. There is a open air vent on each gable end which is the only venting. Please refer to 1st quote for concerns. Thanks again for all of your help.

jlhaslip 03-04-2010 08:55 PM

Code in Alberta is R40 (or R42) for ceilings and there is no way you will be getting that out of a 2x4 construction for the roof unless there is something new on the market. Pink rigid styrofoam is around R5 to the inch, so that gives you about R20 only.
You should look at adding a cold roof system to your roof to get a decent insulation value.
Strip the roof and add a 2 x 8 rafter system on top which will allow you to improve the insulation to near code and have the ventilation you require.

More money, but money well spent.

AaronB 03-05-2010 02:46 AM

My mistake.

I would add as much insulation as possible when you redo the roof. To get the maximum R value, I would definitely use closed cell polyurethane foam.

jeweler 03-05-2010 05:48 PM

First thing is check with the building department to see if a permit is required, and what minimum code standards you will need to meet. You need to confirm the true size of your rafters. I doubt they are only 2x4. Once you know what is there then you can talk to the building department about how you need to rebuild your roof. They will also address the issue of a cold roof or other methods of proper ventilation. Then you can weigh the options of different kinds and amounts of insulation. Based on your explanation this is clearly a job for a contractor. Just be sure they explain exactly how they are going to build your roof and list the components they will use. You will be without any roof for the period between tearing off what you have and when they start the new one. Have them explain how you will be protected during this time. And, be sure they tell you how long...

imtryingtofixit 04-01-2010 07:52 PM

thanks for the help. good advice.:)

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