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From Texas-sized 2 Tiny House For Three

Ruh roh! Roofing and insulation conundrum in the making…

I was perusing the FB feed this morning while trying desperately to wake up after having a weird dream about Brandy and I parkour-ing around the hotel the Austin Tumbleweed Workshop was located in back in April since for whatever reason we couldn’t remember how to get back to the classroom, and there was suddenly an overabundance of extra external stair cases leading to everywhere except where we wanted to go plus giant piles of boulders we were hopping, skipping, and jumping off of (barefoot no less) trying desperately to get back to class before it was over. I’m not sure WTF that was all about, but needless to say I woke up with a headache from mental exhaustion and decided to take it a little slower this morning before hitting the packing-cleaning-loading trifecta hard and heavy again. After all, we are trying to get EVERYTHING out of the Big House today if possible but most likely tomorrow.

Anyway, I came across a post on Bungalow to Go‘s page that was actually photos of Ella Jenkins of Little Yellow Door and Tumbleweed Tiny House Co fame (and who happened to be a presenter at that Austin Workshop I was leaping to and fro for in my dream) gutting her ceiling to removed mold that had formed in the insulation. I remembered her mentioning at the Workshop that her roof hadn’t been built vented and that she used wool insulation that had begun to mold, and suddenly it hit me: I’m pretty certain our Barn Raiser roof also isn’t vented.

Tumbleweed sells their houses-to-go built with professionally blown-in spray foam insulation, which has the highest R-values, provides extra structural support in the walls, and sales the house up air-tight. It only makes sense that the Barn Raisers, built in the same shop by the same guys that build the completed houses, would have similar construction. The only hitch is that we were leaning heavily toward using wool insulation ourselves because I like the low/no toxic material and the fact that it doesn’t require an inner moisture barrier because it dries so quickly and resists mold in optimal conditions (i.e. with proper roof venting), and it even resists pests, too. We are still planning to put an extra sheet of rigid foam board between the siding and the laths over the exterior walls for added protection in particularly cold climes while traveling, but we had planned for the “breathable house” otherwise.

Seeing Ella having to gut her roof and make it breathable (my guess is she’ll retrofit soffits somehow) hasn’t completely deterred us from doing the same thing before we even add insulation, thus circumventing the mold issue all together (I hope!), but it does make me want to rethink the idea of the sprayed-in foam. I would definitely hire that out as I want nothing to do with something even remotely toxic, and that very statement is the primary reason we hadn’t really considered it in the first place. Still, with proper ventilation the off gassing is supposed to cease or at least dwindle to well below measurable safety levels (though I don’t know what those levels are at all) pretty quickly. I can’t deny that having the added structural support would be a big boon to making our regular traveling sturdier/safer as the walls would have that much more impact resistance (for lack of a better descriptor) while driving over rough, bumpy roads. There’s always doing a combo that involves using the rigid foam boards with spray foam to seal, thus almost entirely bypassing the off gassing matter since the foam boards will have done that long before they ever make it to our destination with only minimal spray foam used. That option, however, doesn’t have nearly as much added bonus wall strength, but I would imagine it still adds more than batt wool insulation possibly could.

So, now we have to consider changing up the insulation methods or figuring out how to vent the roof to allow a breathable option like wool. I’m hoping Ella shares her methods with everyone during and after the fact, but in the meantime I’ll start researching online to see if I can find a reasonable method as well. I’m also going to start looking more seriously at the various foam insulation choices so we can really, truly make an informed decision.

InsulationTypeCube

I also just bought 2 rolls of high temp Grace Ice & Water Shield to replace the tar paper presently on the Barn Raiser. We’ve hemmed and hawed about it for over a month, but in rereading a post by Guillaume of Tiny House Giant Journey on their roof underlayment choice and experience installing it, I realized the benefits FAR outweigh the pain in the butt of replacing what’s on the house now. They should arrive at my dad’s place later this week, so we’ll need to get a move on to measure for the skylights and figure out precisely where the vent for the Kimberly stove will live so we can start ordering parts.

For now, though…. Back to the moving trifecta I begrudgingly go! 😛

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