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  1. #1
    Join Date
    Sep 2009
    Posts
    2

    Default Insulating an A Frame

    I am trying to determine the best way to insulate an A Frame that has exposed timber framing. The existing construction is
    1. spruce log rafters
    2. 2x6 T&G board sheathing
    3. 2x3 studs parallel to rafters at 16" OC
    4. 5/8" plywood
    5. 30# felt paper
    6. asphalt roof shingles

    There is no insulation. We need to provide insulation for winterization. What is the best way to do this without touching the interior?

  2. #2
    Join Date
    Oct 2009
    Location
    gastonia, nc
    Posts
    1

    Default Re: Insulating an A Frame

    So as not to disturb the beauty of your plank ceiling, you will have to insulate from the outside, on the roof. Begin by installing 2x6s on the roof to make 5.5in deep bays that run from the top to bottom of the roof,install foam insulating board in the bays, use the highest r-value material you can find in your area,you will be able to apply several layers of insulation to fill the bays, try for r-30 or as close as you can get, more is better, you only get one chance to insulate usually and energy costs are always rising. Apply sheathing as you normally would and shingle, you will also need to apply new fascia, hope this helps.

  3. #3
    Join Date
    Oct 2009
    Posts
    1

    Default Re: Insulating an A Frame

    I would think you would want to create a ventilation space by installing 1/2 or 3/4" strips on top of the rigid insulation, then install your sheathing over that. Of course you would add a ridge vent and soffit vents.
    Joe, the retired carp.

  4. #4
    Join Date
    Nov 2009
    Location
    Galena IL
    Posts
    3

    Default Re: Insulating an A Frame

    look under post for "no insualation under roof"-: We have just completed our roof project on the 1890 Victorian in Galena IL: Same issue as you describe-no insulation, and as a lifelong log and timber home builder, both earlier methods described work fine. We chose the ventless roof type as we are trying to reduce roof profile to maintain historic consistency. After scraping the old roof deck clear, we repaired some soft areas and covered over the old chimmney hole. Just to make sure we did not have structure issues, we opened the cavities at various locations- then used CLOSED CELL foam slow rise foam (open cell acts as a sponge if no vapor barrier inside) We then used 2x6s on edge, applied dupont brand premium housewrap (blue)to the roof deck,and used 2 2" layers of polyiso thermax, and a 1/2" layer of foil faced thermax.cracks were foamed, and seams were taped. Experience and history has shown that multiple layers of vapor barrier trap moisture, thus, we wanted the origional roof deck to breathe. 1/2" osb was fastened with 8" polebarn spikes 16" oc, and occasionaly we used log boss screws to hit the rafters where we could. Water and ice shield was applied over the entire roof assembly. to maintain consitency with the addition and garage, rolled roof venting was applied, but serves no purpose. The Owen Corning shingles we used were lifetime (4 bundles per square), not the cheap ones. Talk to the company representative sales manager, not the warranty department for questions...
    After seeing roofs we did from 1993 on, including 6 on in the same lake subdivision, neither the vented or unvented showed issues of failure. The south facing roofs of both methods appear almost identical! Microclimate and yearly maintenance were the big factors- Given the ability (historic board here has rules) and if it would work in your budget and style, metal roofs are the better option in either method. If you look to save money, try craiglst for materials. Budget numbers:handi foam 600 kits $1100, insulation and other materials $800 (crglst), lumber/bldg materials/spikes $1350, roofing $27 bundle on sale, plus $400 for misc items (wip, edge, vent etc.) Hired out, labor cost would run $150-200 square for all labor to tear off, repair, insulate, sub facia boxes, finish facia and trim, foam, sheathe and lay shingles.
    also, call local log home builders and see their methods. Plus, they can walk you through what you have to do, and have resources.
    Last edited by jwkelly; 07-25-2010 at 02:03 PM. Reason: fix

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