CLT Insulation Questions
I’m in the process of designing a new home that will be built on Table Rock Lake near Branson, MO. I have a desire to utilize Cross Laminated Timber as the roof structure and was hoping to get some thoughts/feedback on my plans for insulation for the home. Attached is a rough design of the wall/roof assembly showing my thoughts on how I plan to insulate the walls and roof of the home. I’ve tried to educate myself on the ideas/concepts of a “pretty good house” but not sure I’m fully understanding the insulation design for my region(4A). Currently my plan is to frame exterior walls w/ 2×6 at 24″ oc cavity filled with cellulose w/ a continuous layer of insulation on the exterior of 1.5″ Zip system R sheathing. I believe this will get me roughly R26 in the walls. The roof would be a 4.125″ CLT panel w/ 5.5″ of poly-iso on the exterior of the CLT panel. I believe this will get me roughly R40 for the roof. Side note, the roof will be UNVENTED since I plan to expose the CLT panel to the inside. Attached is the detail of the wall/roof assembly. Thanks in advance for any help.
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Replies
You have a plan in your head but consider making the walls taller with a flat ceiling covered in cheap fluffy insulation for much less money you get more interior space R60 insulation and the ever reliable vented attic.
I have never been sold on Zip+R. My gut says it makes a weaker wall. See if you can find someone to install your siding over sleeper and sheet foam.
Walta
I would read through this CLT build here:
https://wolfeislandpassivehouse.wordpress.com/category/roof/
From what I understand CLT needs an air barrier on the outside. You would want something to protect the CLT till the roof is installed thus I would put a layer of peel and stick over it and then install the rigid.
quackhunt,
Extending the CLT to form the r0of overhangs is the simplest, but leaves you with thermal bridges at all the exterior walls. From what I understated most CLT roofs use outriggers at or above the foam layer instead.