Theresa Lantz-Huffman

oh yikes! I used the sunnyside oil this summer just to oil some boards outside and thought it didn't smell strong at all (i have a really sensitive nose too).. so was excited that I could just use that.. thats such a bummer, why does there have to be so many chemicals in everything 🙄... are you able to keep your windows open at all? thank you for the heads up, i sure appreciate it..keep us updated if you can.

We are getting to the stage of our passive solar straw bale house build where we will be soon adding insulation.  We did go the route of venting our cathedral ceilings (thanks to the help of many from Permies  )  Should mention it is a metal roof and we will be using lime plaster. We have some rockwool we will be using, but our main source will be sheeps wool insulation. We live in North Dakota zone 3/4, so vapor barrier I guess is a must with our weather. but I CANNOT for the life of me come to terms with the idea of using PLASTIC all over our ceiling!?!? its not very green and all i can picture is it CAUSING mold and moisture problems on the insulation side? surely there has got to be a better solution?  

please tell me I am overthinking this part or that maybe there is a straight forward answer? i have tried to research on this as much as I can but it really isn't easy finding answers when EVERYONE has their own two cents that seem to contradict each other.  At least with this group I know there are many like minded people that are willing to collaborate with each other on their ideas to come up with a solution..

Thanks to all who take the time to read this!

Haha I wasn't sure if maybe R20 was a possibility but sounds like its not, thats what I needed to hear!  your right, we are in zone 3/4 north dakota

me again,
soo I have researched more into the rockwool and am now reconsidering due to all the added binders/chemicals. Has anyone ever used sheeps wool or know of how efficent it is?
Rockwool      ~$4000(R30 - 7.25")
Sheep Wool  ~ $5600(R20 - 5.5") or $7000(R26 - 7'')

We were originally quoted $10,000 for spray foam so these prices aren't completely scaring me away ...We have cut our OSB and our blocking so we are ready for tin this weekend!!  Thank you all for the information on venting, it has been such a great help.
If anyone has any advice in regards to sheep wool that would be wonderful as well, also if you think R20 (5.5") could be sufficient in a 2x10 rafter?!

thank you for that extra advice, im sure hubby will make something work between the two! whats your thoughts on how much soffit ventilation would be needed?

and yes we will for sure have that part finished before we put the metal roof on!

If I go the rockwool route, it looks like I can still do the R30 at 7.25" thick correct(our rafters are 2x10)? i am unsure how much soffit ventilation I need???

We have some extra work ahead of ourselves now beings we have all of the OSB up already on all roof systems and making holes in our blocking (thankfully it is just one row), but I am happy to have found an alternative to the more toxic spray foam AND it is half the price! 5k for rockwool and was estimated 10k for spray foam

Eliot Mason wrote:Insulation and air movement are critical building functions, getting them wrong can have tremendous (and expensive) consequences.

Rockwool insulation is a great product - just be sure to have a cheap bread knife (the serrations are critical) to cut it.

It looks like your roof framing is 2x8 or 2x10 - creating a much deeper cavity than the r23 Rockwool batt.  thus as Mike says if you push the batt in betwern the framing and keep the batt flush (or nearly so) with the interior plane you will have a good 2+ inches of air space under the roof. BUT here's the rub - EACH pair of framing members creates a little "attic" - there is no way for all that air to mix and mingle and flow.  Further, I see some structural blocking between the roof framing, further segmenting your "attic" into a bazillion pieces.  

To create air flow the attic needs to have low-point air entry and high-point air-exits so that as the air in the attic warms it just pumps itself out.  I would have used shorter blocking (flush on interior, gap on roof side). Fortunately you don't need the full height of those blocks, so get a hole saw and drill away the top (I'd think 2 x 3" holes wold do).  The roof on the left of the picture is complicated because it abuts another living area; the roof on the right looks like you could have both air entry and air exits in the roof fascia (so long as you don't have blocking in the way).

There are fancy products for making a continuous vent along the peak of a roof. Turns out the same idea can be used here ...  the roof sheathing would need to stop 2-3" from the wall intersection, creating a window for all the air to escape.  The vent layer (a corrugated plastic sandwich thing, about 1/2" thick) would be placed at the edge of the sheathing.  You would need your flashing to come down the wall to extend down the roof far enough to cover the vent.  Yep, that'd do it.

And yes, others have thought of this.  Excellent. For instance  https://www.gaf.com/en-us/roofing-products/residential-roofing-products/ventilation-and-attic-vents/exhaust/hip-vents/cobra-hip-vent

thank you for such thorough reply, i feel like there is most definitely hope out there for the wool! what type of insulation would you do if this was your house?

ok thank you, ill look into both options.

im starting to really understand how to correctly do this with wool in general but not with my roof system!  heres more pictures to shiw why i am question (only the lower roof is the question as far as getting the air to flow out anywhere)

Hello,
We are building a straw bale house with standing seam roof.  I recently posted about ventilation with a spray foam house and now I am even wondering if that is really a good option.  I am now looking into the rockwool insulation which seems pretty ideal. However, I am clueless on how to properly install either of these methods with a vaulted ceiling. I have been researching the ventilation baffles...is this a must for both scenarios or just the wool? and if so, does there need to be one in EVERY rafter bay?  Our house we are building is a clerestory type roof system so there is a knee wall (can this act as an attic? how?) connecting both roofs as well as a typical gable style garage roof.
If anyone can lead me in the right direction as I feel there is not enough solid information out there and others just do it however they think works when in all reality there is more than likely a better option to keep moisture out of the sheathing, etc.
Thank you,
Theresa