Bishop Passive House: Exterior Insulation Pt 2

[@ducoh2093]

wood fiber is simply the best, eco products are the best, healthy materials to live in.

[@kingduck3192]

Have you used the thicker exterior wall boards I’m looking into this for a timber frame house instead of SIPs. I love the sustainability and health aspects vs rockwool or foam.

[@cairncollaborative7736]

I've used a whole lot of things. This gutex; rockwool; polyiso foam; and Zip-R with the 1.5" insulation which might be what you are talking about as "exterior wall boards". There are too many things at play, too many unknowns, to say which is best for each particular situation. Availability, cost, desired effect, motivation, etc. Ours here were health of client, workers, and planet.

[@tomwilliams5215]

Hi….I have purchased the Multitherm 4000, Mentos, and intello. The plan for the exterior is OSB, then mentos, then the Gutex, then cladding. After reading in another comment about possibly putting mentos layer over the Gutex, I now wonder for the northern Idaho climate which system might be better. Do you have time to give me your thoughts on that? Thank you for the videos, by the way.

[@lavrentichudakoff2519]

I wish I know about this building product when I built my place in the Cabinet mountains northeast of Sandpoint.

[@cairncollaborative7736]

Hi Tom, Didn't see this comment until today. How did things go?

[@kermitefrog64]

I like the insulation. Nice project. What company did you purchase the wood fiber insulation from?

[@cairncollaborative7736]

We purchased it from a lumberyard in Ashland, Oregon. There is a company in Maine now making wood fiber insulation boards. I’d order from them next time. www.timberhp.com/

[@strattonworthy]

Hey, I have a question on the fixing of the cladding: doesn't the use of the staples puncture the AdHero membrane behind it? also the same with the screws for the battens. you didn't use/consider something like tescon naideck?

[@cairncollaborative7736]

Hi there. Sorry for late reply. As much fun/work it was to create the video series, we are building in the field everyday still and don't get to the replies as often as we should... obviously. The staples would puncture the adhero, yes. But we are talking really splitting hairs at that stage. It's similar to when folks use Zip - with it's ingrained membrane - but also puncture that membrane with every nail that is holding it in place. You need other, much-greater additional forces to move any type of water that miniscule, micron's wide "hole". In the real world, it doesn't happen, particular since this adhero has a layer of woodfiber insulation over it, then a rainscreen gap, and than another layer of either stucco or wood cladding. Same as the screws used to attach the insulation. They penetrate through the insulation, through the membrane (which technically "seals" around that screw) and then goes into a framing member on the inside. You'd need some outrageous amount of exterior forces (above hurricane strength winds, for example) to be applied DIRECTLY to that micron hole for any sort of water to penetrate all the way into the home. At a certain point, I don't think about that happening. If that's what's happening in the world... we've got bigger problems to worry about on that day! (The end is nigh!! ). :)

[@7_v610]

Thanks for the great video. Also to add, also, if I may, that wood fiber boards allow the building to breath, contrary to what happens with its plastic counterparts, which is a crucially important advantage of this product! And, in addition to the above, wood fiber panels do not emit the compounds that polyurethane and polystyrene do, and which have been proved to cause either cancer and/or respiratory or other problems to the people living in buildings insulated with such products. Especially polyurethane foam, should have been banned from the market a long time ago, based on what it has been found to cause to humans. I really applaud you for highlighting the need to use eco-friendly materials in our buildings. This exemplifies how each every one of us should be thinking and acting; it’s about caring about the planet and our fellow human, and not just about how to keep a few more bucks in our pocket right now, but absolutely disregarding that we will pay multiple amount of money by staying in a building and planet full of shitty plastics (e.g., polyurethane) in the near future!

[@michaelhorgan6640]

Sorry I missed this reply. I actually wrote a story on our IG page today about something like this...the bigger picture. We all need to be thinking about it, hard.

[@runmarkrunheinrich]

You want the building to breath through an ERV or HRV. The more important point is this material is vapor open and you can have your air/water/vapor control where it belongs using membrane materials and this thermal layer gives you a lot of drying potential and won't trap vapor or water where you don't want it.

[@ArthurDentZaphodBeeb]

Have you used TimberHP rigid wood fiber insulation? It seems they've finally begun production in Maine. Hopefully, it's less costly than Gutex.

[@cairncollaborative7736]

We've asked them to get some in California, but we were told they are not supplying to CA, yet. Asked again recently, and we haven't heard back. We've got a ton of projects where we'd love to. Right now, it seems a very exclusive product to get your hands on. Wish we could.

[@slew8941]

This is a great video. I don’t know much about the wood fiber insulation. My concern would be using this type of insulation in cities that termite problems.

[@michaelhorgan6640]

Thanks Stacie. On a project like this, the materials are sealed so, so, soooo carefully and tightly from the outside environment in a variety of ways that it would be impossible for termites to get to the material. Additionally, termites need moisture/water and not *just* a material to eat - which will not occur. If materials are dry - or even better if materials are used that *can* dry if they get wet, then termites don't have the wet food they like. :)

[@dressjess]

Great videos and learning resource for passive building. How does this exterior insulation stay dry? I can see the weatherproof membrane behind it, and you mentioned that it dried quickly after lots of rain but how? It looks like it would be so absorbent. I'm intrigued!

[@cairncollaborative7736]

Great question! The specific product that we used from Gutex for this build (Their multitherm line) uses a paraffin wax that helps the insulation to shed water. It was pretty incredible to see it dry out after a large storm we had!

[@TheRealMrLaserCutter]

Why not put the weather membrane on the outside ie over the gutex?

[@cairncollaborative7736]

@@TheRealMrLaserCutter You can do that. Gutex has a few different lines of insulation, and this particular one does not require the membrane on the outside of the woodfiber. We've done it both ways, however, using the other lines of woodfiber insulation.

[@johnwhite2576]

Why not rockwool, ? Esp in fire prone California ?

[@michaelhorgan6640]

Embodied carbon aspects; the yuckness of working with Rockwool for all of us in the field; the compression factor of woodfiber compared to Rockwool Comfoboard, etc. There are a few reasons. I'm not anti-Rockwool and have just used it on a sauna I've built at our own home here, and I've used it fairly often in the past - but mostly interior applications. I just prefer woodfiber for exterior insulation. We may use Rockwool on an upcoming PH though for the very reason you wrote. Though Gutex performs just as well during field tests under fire, it does not have the actual WUI rating required for high-severity fire zones in CA - which is a shame.

[@stevecrawford6958]

@@michaelhorgan6640 what's the cost comparison for comfortboard compared to wood fiber, install excluded.

[@cairncollaborative7736]

@@stevecrawford6958 Hi Steve, Costs are changing so rapidly these days, across the board. Rockwool will be less expensive, though materially not by much. The different in using Rockwool/Roxul is that it's pretty readily available, and finding and shipping Gutex is the killer. It wasn't when we built this, but it is now. We can't get Gutex at the moment, so we're largely changing to Rockwool now, too, until the world steadies itself and materials are available to us again.

[@HickoryDickory86]

@@cairncollaborative7736 It would probably help if Gutex has some local manufacturers, but they don't as far as I know. It's all made in Germany, and they've had a rough couple of years and this winter will be absolutely brutal. I wouldn't rely on German products for the foreseeable future. Making the switch to Rockwool for the time being is the way to go.

[@stevecrawford6958]

@@cairncollaborative7736 thanks for the candid response. i think there's supposed to be some other companies offering wood fiber soon which will hopefully balance things out, in terms of both supply and price.

[@KamikazeeNYC]

Great videos……when are you posting some new ones??????

[@cairncollaborative7736]

Working on it at the moment. We currently have three projects that are fossil-fuel free underway - two large remodels, and one new build. Getting the video team back together :) We're all a bit shy about camera stuff and being, seemingly, not-very-humble. We should get over that :) We get asked a lot to make more. Thanks for the nudge! (Also, it's expensive to make them... We don't get paid, and we don't get sponsors. It cost us over $10k to make this series alone...)

[@SolarDrew]

Do you have any videos on window installation and exterior trim build for them?

[@michaelhorgan6640]

I believe we have some videos about our installation of our windows, yes. The trim detail we used is a simple box-frame with a 2-degree slope on the head and sill casing. However, our overhangs that we've designed into this home prevent almost all rainwater from reaching the windows.

[@Aboriginal_Alien]

I am sold on this product. I live in the NC. I heard there is a plant in Maine producing this product. Has anyone used it?

[@cairncollaborative7736]

Not sure the plant is fully up and running, just yet. But they are getting close. Check in with our friends New Frameworks in Vermont. They've got a pretty good bead on that corner of the world.

[@boedillard8807]

What's the R-value?

[@cairncollaborative7736]

Hi Boe, The R-value for this product (gutex multitherm 40) is 5.7.

[@davidbruce5377]

Did the Adhero stick to concrete, or did you apply a primer?

[@cairncollaborative7736]

Hi David, At the slab where the Adhero meets the concrete, we utilized contega multibond (acrylic adhesive) to act as a seal and stick the membrane to the slab.

[@comfyhome]

Thanks for the video series, it's excellent. When you mentioned that it dried out in 24 hours, was there also significant wind washing on it during that period? How do you think it would hold up in months of constant drizzle with not much wind? Have you ever tried leaving a sample in a bucket of water for a very long time just to see what happens? I think wood fiberboard is definitely one of the most promising options for exterior insulation, but I'm trying to do my due diligence. I've heard Christine Williamson remark offhand twice ( kzbin.info/www/bejne/qoaclJyNisuAZqM , kzbin.info/www/bejne/jpfMg4yHd7pnla8 ) that she feels it's somewhat risky to have moisture sensitive exterior insulation (in one video she's talking generally and in the other she specifically mentions Gutex). However, she fully admits it may be due to her own ignorance with this type of insulation.

[@michaelhorgan6640]

Thanks for the compliments on the video series. We funded it ourselves, so we think we're being fairly objective :) We did not have wind washing on the product in that dry out time. We had heavy sideways rains here for a few days. Everything was saturated completely. Everything! It was wild. I don't think any product in the world would hold up well under months of constant drizzle - unless it is designed to do just that, i.e. siding, stucco, etc. Insulation materials (for the most part.... although there are a few exceptions out there in the wild, but pretty experimental) are not meant to be left exposed to elements, particularly rain, for extended periods of time. They should be able to become wet or saturated and dry out though, because no wall assembly (even though we'd like to hope so) is perfectly waterproof forever. To that, I have not left a sample in a bucket of water - at least not intentionally. I did, however, leave a piece of Gutex and a piece of Rockwool outside my house for almost a year, accidentally. Just dropped them on the ground after a presentation and forgot them. A year later, I can say that one of those samples (about 1' x 1' pieces) help up just fine, and the other was peeling apart in fibers. The woodfiber board was fine, and the Rockwool or Roxul was pretty mildewy. To be fair...neither of those products should be left outside exposed as they were, so it's not a real-world situation. But it was interesting... To be fair, woodfiber board is used extensively around the world in places with much worse climates than the US. It's used all over New England, specifically Vermont and Maine, where some of the worst and wettest climates exist in the US. If you want to talk about moisture sensitive insulation materials, foam board is extremely moisture sensitive. It can't dry. Rockwool, Gutex can. I like both of those. Gutex has a good density over Rockwool/Roxul. TimberLab is making woodfiber boards in America now, too, so will be interesting to see them begin shipping.

[@comfyhome]

​@@michaelhorgan6640 Sorry I somehow missed this earlier. Thanks for the excellent and comprehensive reply. Was the Rockwool a piece of batt or was it Comfortboard 80/110? If the moisture sensitivity is mostly on par, I suppose it then comes down to the vapor permeance and how much that matters for a particular assembly. It looks like TimberHP boards may actually have higher vapor permeance at 40 US perms at 1 inch vs 31 for Comfortboard 80. Somehow I was under the impression (I think, ironically from a presentation by Rockwool...) that Comfortboard had higher permeance.

[@michaelhorgan6640]

It was Comfortboard 80 that was left outside. Again, though, not really a great comparison. They were both just dropped on the ground while walking in the front door :) not really a "test". @@comfyhome

[@tubulartuber]

this is a cool assembly. can you share what the thought process was for putting the peel and stick membrane on the sheathing and not on the exterior wood fiber board surface? I've seen it done three ways now: 1) no membrane--wood fiber insulation serves as water control layer, taped plywood sheathing on the interior is the air control layer - kzbin.info/www/bejne/paicZHWhd655Z6s 2) peel and stick membrane applied to the exterior of the wood fiber board insulation - kzbin.info/www/bejne/r6K4p3luosiirLM 3) your video's method It seems like all three methods are fine, I'm just not sure what the subtle differences are. Maybe one is just easier to do?

[@cairncollaborative7736]

Hi, glad you found our videos! There are a couple different things at play here. Regarding the 2nd and 3rd option it really depends on the type of wood fiber insulation that we chose. We used a company called Gutex who makes a couple of different kinds of wood fiber insulation depending on the usage. The Multitherm line that we used utilizes a paraffin wax on the exterior that actually helps it to shed water. Because of this, we were able to put our membrane onto the sheathing and leave our exterior insulation exposed. If our exterior insulation did not have this wax incorporated, we would have needed to use a different type of membrane to protect it from bulk water. The first video you linked looked like a pretty cold climate in the Northeast where they were worried about humidity in the winter and moisture getting into the walls from the interior. On this particular house in SLO, we were not as concerned with humidity entering the walls from the interior, but more concerned with keeping water and our heavy fog moisture away from our wall assembly. (And using a rain screen assembly so that when water does inevitably get in, it has a place to dry to.) These decisions depend on the specific project and specific climate and what you are trying to achieve with the building. There are lots of different ways to achieve a similar standard/ goal so it really depends on a particular set of variables. We wouldn't necessarily use this same wall assembly in all of our projects, but it worked for what we were trying to achieve here. Hope that helps!

[@tubulartuber]

@@cairncollaborative7736 Sorry if this is a double comment, I was trying to edit the old one and it gave an error. ​ @Cairn Collaborative Hi, thanks for the detailed reply! It makes sense that each assembly is specific to a particular climate/site application. I appreciate the time you took to detail your thought process for your environment. I have a related question: while investigating these assemblies, I came across a sort of blanket recommendation (which I have yet to find the paper or study detailing the reasoning why) -- this recommendation says that the interior materials should have a permeance that is 5x less than the exterior materials (German DIN 4108-3 regulations / US DOE guidance, foursevenfive.com/blog/a-high-performance-roof-should-be-vented-how-to-do-this-properly/ ) I find this blanket recommendation a little confusing, because I know that taped sheathing as the combined air and vapor control layer to be a fairly common method in higher performance builds, so maybe the recommendation is not necessary? Or maybe OSB is more common than plywood, and with its reduced comparative permeance, it is easier to find exterior materials to suit the 1:5 ratio? Or maybe most forms of exterior materials are not so airtight that it really matters? What are your thoughts on this blanket recommendation?

[@kevin3434343434]

Sawdust is also very bad for your lungs. Just saying...

[@michaelhorgan6640]

True. Unfortunately, I'll sadly say that after cutting wood since a teenager, I think the sawdust here is a miniscule percentage of what I've inhaled over my career. We did wear masks *most* of the time when cutting, as we often do (but...not always). Thanks!

[@thomasschafer7268]

Für was soll das erste Bild stehen? Für unwirtschaftliches Arbeiten? Die Platten haben 4 Seiten Nut und Feder . So wird das nichts mit wirtschaftlichen Bauen !!!👎👎😄🇩🇪

[@cairncollaborative7736]

🤷‍♀ I wish we understood what is being said here!!