Mariah Wallener

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since Feb 02, 2011
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Zone 8b (Canadian Plant Hardiness Zone)
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Cowichan Valley, Vancouver Island, Canada
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Recent posts by Mariah Wallener

Thanks so much everyone for your comments and input. And Terry, for what it's worth, I did not find your tone abrasive, though I appreciate Bill's comment because I can be sensitive.

Terry, I have read many articles by John Lstiburek. In fact, it was his articles that inspired my slab design: we put 3" of Type II EPS rigid insulation under the slab and then another 2" of XPS around the slab perimeter. You can read about that on my blog here.

I am not surprised that I'm using the word "breathable" in a way that is not used by the industry. Perhaps I should just stick with "vapour permeable" though the former has a nicer feel to it. Some of what you talked about went above my head, but I can address a few points nevertheless.

Summers in our local microclimate are very dry, much more so than when I lived just across the Salish Sea in Vancouver. So I anticipate that my walls will have a long time to dry off in-between winters which I hope will prevent any potential issues with mold though I don't expect any. Our dry summers is reason why I don't anticipate many situations where outside humidity is higher than that indoors, but it was nevertheless my intention to have walls that can breathe in both directions. I will have to look into the paint situation but it is doubtful I will go with lime plasters or anything else like that - very labour intensive, small pool of skilled professionals here that can do it, and my budget is tapped out. Plus I have my pretty paint colours picked out already.

Interior humidity is really only a problem here in winter when the doors and windows are closed up and that lasts from late October to early April. In fact, for the last 3 weeks now I have had the windows open and the front door open during the day in our little mobile home. Even before that we were in a situation where the heat was needed in the morning and evening but off during the day. Our new home will have a woodstove and I anticipate that when it is fired up we will often end up opening doors or windows by midday. This short heating system and no need for mechanical cooling in the summer means I can get away with a more lax attitude towards sealing my home up airtight or needing an HRV system (or as I call them: iron lungs), because for most of the year the windows can be open.

With that said, of course the new house will have exhaust fans in the bathrooms and kitchen. We were also forced by new code regs to install an HRV system with ducts leading to all bedrooms and the main living areas - was not my desire to do so because of aforementioned short "closed up" season but it had to be done. So we will have the ability to dehumidify if necessary, though I'm betting we won't need it. In fact, I'm anticipating that we will barely need to run the HRV system at all, which is why I was ticked off that I had to shell out $5000 bucks for one.

And yes you were correct about me meaning to say "thermal bridges" and not "thermal breaks" in regard to fastening the exterior insulation system to the outside of the sheathing, my mistake. And I don't know that the engineer did not use any computer modelling, I didn't ask. And yes, while the outside insulation has an R-value of 12, there is also insulation on the inside of the sheathing, between the studs - 5.5" of Roxul batt insulation R = 22. Our building code requires wall insulation of 20, while recommends 30. We have total of 32 so I'm pleased with that.

I'm a huge fan of Roxul which is why we used it everywhere except under the slab due to the limited underslab testing, as Terry described. My builders love the stuff and say it is fast growing in popularity here.

Let me know if I've missed anything. Some of what was said I did not understand.
8 years ago
Hi Kevin! And thanks for your interest and great questions.

I was aware that latex paint is a vapour retarder, but my understanding was that it was a pretty poor one. However, I did not consider the effect of multiple coats of paint. I will definitely look carefully into our choice of primer and paint to ensure I don't end up overdoing it on the inside walls, thank you for that tip.

I understand that under certain conditions vapour may move from outside to inside and I'd like the walls to be breathable in both directions, although our summers are pretty dry and high humidity occurs almost exclusively in the cool season.

The rain screen is Slicker (material looks a bit like a plastic dish scrubbie) and yes, it is vapour permeable. And it will be open at top and bottom as is required by our code (nearby Vancouver, my home town, was home to the "leaky condo crisis" of the 1980's, which I think birthed the rainscreen industry!).

As for those nasty windows, I was referring to our current housing situation which is a 30 year old mobile home that is deteriorating pretty quickly (when we bought this property it was supposed to be "temporary housing" but it took us longer than anticipated to start building the new house). The windows are the old style double panes where each pane opens separately and there is just a big air space between them. I'm quite sure the seals have long gone bad, which probably explains the condensation inside. Our new house has fantastic windows.

As for the plywood seams, no we are not taping them. I confess the topic of sealing a house airtight is where my opinion departs from the current green trends, and I've had many a lengthy discussion on green building forums about this, lol. We are using house wrap as an air barrier, but we are not going to any extent beyond code in that regard. I'm pretty stubborn about not wanting an airtight house, but I can afford to hold that position because of our mild climate and short heating season!

You asked about whether the engineer modelled the wall system. I'm not sure I understand the question. He provided detailed drawings for the building inspector so that it would get approved. But I specified the structure and our builder specified the attachments (how it would all be put together). Roxul, the manufacturer of our mineral wool insulation, has already approved the use of their product in this fashion and confirmed that when done so properly, no vapour barrier is needed. So really the engineer's job was just to confirm for our building inspector that it would work the way we said it would.
8 years ago
Hello permies! It's been a while since I was on here discussing plans for our new build, and now the house is halfway complete!

Inspired by so many discussions here on natural building and breathable walls (and so we are all on the same page, by "breathable" I mean vapour-permeable), I designed a breathable wall system for our new house that is somewhat unconventional around these here parts. Since we were going with conventional stick-frame construction and had a skookum crew of trustworthy and talented builders, I wanted it to be simple enough that time would not be wasted training anybody on novel techniques.

The end result is a stick-frame wall with Roxul mineral wool insulation on either side and NO vapour barrier! We had to get an engineer to sign off on it, since here on the rainy West Coast of Canada, the industry is currently involved in an intense love affair with vapour barriers and trying to keep moisture out of walls (while living in what amounts to a cold sauna, ha!). And when the framing crew arrived, I received much praise on my design. They said they'd seen nothing but trouble with people relying on vapour barriers, and predicted that the hangover would soon prompt a change towards more breathable homes (and not, instead, on costly mechanical dehumidification systems).

The exterior insulation will be attached in two layers. The first involves vertical 2x2 furring strips with 1.5" of Roxul comfortboard in between. Then a second layer of furring strips will be attached horizontally, with another layer of 1.5" Roxul comfortboard placed between those. The screws for the furring strips will be placed such that no one screw penetrates through both layers, so the only thermal breaks will be a 4 inch deep 2x2 bit of wood. On top of that will be a layer of rainslicker rain screen material, then our vertical board-and-batten siding (which will be secured to the horizontal furring strips).

As a former medical research scientist and current stay-home mum, I have zero experience in building, so I am particularly proud of this wall! I also want to give a shout-out to Jay C. White Cloud, who patiently answered my endless questions while I was coming up with the design.

Here is a link to my blog article about our walls:
8 years ago
Oh that is good news, thanks both of you!

The drawing is exactly what I had in mind...

I'm getting close to being next on the list for Art's book from the library, hopefully it will have some more info on what you have described.

Can either of you point me to any other resources for designing and building such a system as pictured/described?
8 years ago
I had this idea in my head that I could create a little stream running from a greywater outlet pipe down to an area where I would love to have a pond. Plant the right weeds along the stream, use gravel, etc. and it would be filtered until clean by the time it reached the pond.

Then I did some research (put a library hold on Art Ludwig's books) and was browsing Ludwig's website. And it seems like none of what I imagined is doable with greywater. So I'm left wondering if I should bother trying to install a greywater system. It can't be stored, and it can't be used to water vegetable gardens. So what can I do with it?

I don't have lawns - I have fields that I let go dry and dormant when the rain stops. And I don't care about them being green anyways.

I don't have an ornamental garden. I don't have fruit trees (though I may get some after our house is built).

I grow a handful of veggies and plan to expand my garden.

It rains plenty here in the winter, so what would I do with it then?

I hate seeing perfectly good water running down the drains, my biggest peeve being the cold water as I wait for the hot water to show up (wonder if small, on-demand heaters near "wet" rooms would be less wasteful?), so I would like to avoid that waste, but this just doesn't seem practical.

What am I missing?
8 years ago

It is called "raised earth" because it is comprised of earth as well as stone and "rises" above the sites "natural grade."...What holds it in stone and/or rammed earth in most of the vernacular designs...

Oh, I think I get it. Kind of like how "raised beds" (for gardening) aren't "up off the ground" but just "higher than ground level". Thanks!

8 years ago
I read through this post once before, but decided to read through it again and have understood it so much better for doing so.

Jay, since the topic of this thread is the raised earth foundation, could you describe it in a bit more detail?

I'm confused about the interface between earth and ground (and whether there is one). So you start by digging down deep, then filling it all with packed gravel. I can see how this mitigates moisture issues as the rain drains away and the moisture from the earth can't get up to the floor of the house. I am also supposing that any condensation or dew that forms on the gravel/rocks drains downwards due to gravity. You place big foundation stones in the corners (and perhaps more than that) or stacked stones as either plinths or a continuous foundation wall - but with the latter it is a "vented crawlspace" I have this right so far? I'm assuming it is "vented" or open on the sides so that air can flow through and circulate and dry out any moisture there such as dew or condensation, much like the old "leaky walls" of buildings kept them dry (albeit very drafty; not an issue when it's under a floor).

Now where I'm confused: Where does the packed earth come in? Is this put directly on top of the gravel? Why is it called "raised earth" then? If the packed earth floor sits above the ground then what hold it in place (on the bottom)?

9 years ago
I just read this thread and it really spoke to me because I've been having some discussions with Jay about T/N building after I posted about a passive solar conventionally "green" (i.e., airtight, superinsulated) home we are planning to build this summer.

Rufus really spoke to what is in my head, and how I'm feeling right now. While he and Jay went back and forth about semantics, I believe that for most people in American/Canadian society it is not so simple as whether the stuff actually works or is proven.

Perhaps some of you are familiar with Maslow's hierarchy of needs model, which essentially states that there are basic human needs - shelter, food, security - that must be met before people can devote their minds to "higher" needs such as personal growth and development. In other words, take a single mother living on the edge of poverty, fearful of an abusive ex-partner, and at risk of losing her home if she misses work a couple of days to care for her sick child because she won't be able to pay the rent. This woman has no "room in her mind" to contemplate higher needs such as a change in lifestyle (for example), such as becoming vegetarian (which involves doing the research, learning new recipes, learning new shopping habits, monitoring nutritional least until it becomes more established and automatic) because her mind and life are fully taken up by meeting her more basic needs.

In my experience, going "against the grain" or "outside the box" - i.e., doing things in a way that is significantly different from how the people around you do things or what they believe to be "common sense" - requires that bit of extra "room in one's head". And room in your life, for that matter. If your life is crazy busy and your schedule is packed, you likely don't have time to consider a deliberate move against the grain (e.g., selling your car and cycling everywhere, or challenging yourself to remove plastic from your life).

Now move on to the John Doe family that Rufus described. I'm facing a similar situation. My family desperately needs a new house and we have waited five years to build on our property while we've been living in a rapidly aging, tiny mobile home. The budget is tighter than we'd hoped but we can't wait any longer. We have strong feelings about what we "need" (which, as Jay pointed out, is really about what we "want"), but those wants have been honed over years of actively thinking about what we want most and what we can live without, and to start over again with re-assessing needs/wants takes time and "room in our minds" that we feel we've already spent. My husband doesn't want a "hobbit house" or "hippy palace" and he's unlikely to take my word over a professional builder's when it comes to, for example, the need for a vapour barrier. Especially when our life savings is at stake. To consider switching from a "conventional green" building (superinsulated, airtight, passive solar) to a T/N building requires us to essentially start at square one and re-learn everything we thought we knew about buildings (not because nobody else knows how to do it, but because if WE don't understand it enough to believe in it, we can't feel good about choosing that path nor can we be confident about the builder we choose).

I've made several "outside the box" choices before: when I became pregnant with my first child, I decided I needed to relearn everything I thought I knew about childrearing. I went way outside the box and ended up raising my kids the "traditional/natural" way, which was pretty much foreign to most people around me. That took time, energy, and "space in my mind" to get from "hey, this is interesting, I want to know more" to "we are going to do things completely different from what most people expect". Importantly, it took enough confidence to stand up against "professionals" who warned me that what I was doing was just plain WRONG.

I did the same thing with education: my children have been unschooled since birth. Very outside the box.

To do things like sleep with your baby or not send your kids to school requires that you have enough faith and confidence to proceed along a path that few around you have chosen. And you have to do enough research to be able to stand up to the "professionals" who will insist you have no clue what you are doing and predict dire consequences.

So...for me to go from "conventional green" to T/N would require me to do a whole bunch of research, gain enough confidence to fly in the face of "professional advice", find a like-minded community for support, and find local professionals who can help me achieve my new goals.

The difference between the kids and the house is this: if it turned out I wasn't happy with the way things were going with my kids, I could immediately switch things up. I could have sent them to school within a few days of deciding unschooling wasn't working. I could have run out and bought a crib or weaned my children early if I felt things weren't working out the way I wanted them to. But when it comes to building a house, mistakes are not only time-consuming, they could potentially bankrupt us. As a parent, I am solely responsible for executing the style of parenting or education I want, but I will not be involved in the construction of our house at all; I have zero skills in that area. So I'd be trusting someone else to execute my vision and that is really scary to me.

So while I am intrigued by T/N and I'm trying to learn some stuff from Jay so that I can bring some knowledge and good questions to the table when we meet with our builders, I have to say that I'm also feeling pretty intimidated and overwhelmed at the thought of starting over again and relearning what I thought I knew about green building.

Rufus is right about all the societal things that get in the way, the realities of living in a culture and a part of the world where such knowledge is rare and flies in the face of what we believe we know about things like vapour barriers and the insulative properties of natural materials. It doesn't even matter if we do it all wrong (like people making their babies sleep alone when they are designed to sleep next to another human) because when that is what "everybody does" we, as humans and social creatures, require a great deal of "mental energy" and "room in our minds" to go against the grain. We're wired to absorb and take for granted the cultural knowledge that surrounds us so that we aren't all re-inventing the wheel. This has many benefits, but it also means that when "common sense" makes no sense at all, it is difficult to get minds to change.

I applaud Jay for his tireless efforts to promote the message that T/N is a possibility and that anybody who truly wants to follow this path CAN do it, no room for excuses!. I applaud him for pointing out that so many of our needs are really just wants, that so many of our can'ts are really just won'ts. He is calling us all out on our bullshit and I respect that immensely. With that said, it may be possible to do T/N with no extra cost or time than a conventional build, but I believe that is only if one has already put the time and energy into educating themselves, forming the support network, and establishing confidence within oneself to proceed against the grain. That takes energy and space in the mind that many modern families simply don't have. I'm not sure I have much of it to spare myself these days, so I can totally relate to what Rufus wrote.

9 years ago
This is so helpful, thank you!!

I love the wall truss system, allows you to build super thick, well insulated walls. So, next (obvious) question: what infill would you use? I believe you suggested mineral wool batt, what about densely packed cellulose? Other options?

Do the "ribs" not create thermal bridges across the wall thickness? (I suppose this would apply equally to regular stick-framed walls)

What other layers are there in this wall structure? Gypsum (drywall, yes?) on the inside? Vapour barriers? And what sort of exterior cladding can be used?

So you have a thick wall filled with wonderful insulation - is the idea to make this wall breathable? If not, is the home sealed tight and an air exchanger used?

Wrap-around porch, why is this needed? I confess, I've always disliked them (I totally get why you would want them in places that get super hot). Our winters are dark, grey and dreary and I want as much light as possible streaming in through the windows. And I want to see the sky out my windows! And how does that work with passive solar anyways?

9 years ago
This is a spinoff thread from the "best backup heat source" thread.

Jay C. White Cloud wrote: "There are many "hybrid" and other "t/n" construction modalities that may very well be within your budget and time constraints. A simple timber frame with wall truss thermal diaphragm insulated with mineral wool batt and board then a cold roof/rain screen wall system is very viable for banks, super easy to build, breathable and also has great resale value because of the super insulation and the aesthetics of a timber frame superstructure."

I would like to hear more about this. First, could you explain what a wall truss is in the context of a timber-framed skeleton? Second, what is a thermal diaphragm? And third, what is a cold roof/rain screen wall system?

"[An] OPC steam wall or plinth system is tolerated, (geopolymers are taking off all over the country and can be found now in many locations...yours may have one now??) and then either a traditional "doma" entrance and egawa (small porch) all around the structure plinth foundation with insulated wood floor."

So if you are talking stem walls or plinths then I'm assuming the insulated wood floor sits on top. Is this a standard joisted floor? Can you describe the wood floor in terms of how its constructed and insulated?

The description of the "egawa (small porch) all around the structure" makes me think of a wrap-around porch, is that what you are talking about? What role does this play?

"Get yourself into the structure with wood heat, then ascertain "empirically" what other additional systems will serve you best. Radiant heat can be added very easily later on if the building is designed by a competent designer in these t/n modalities."

This sounds great b/c I'd rather actually live in the house and experience what is needed before investing in a backup heat source that may be too little or too much. Can you explain what design features would make it easier to add a system later on? What radiant heat system would you be referring to, is it baseboard-style?


9 years ago