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Framing for clay slip chip walls

 
Tim Nam
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Location: Arcata, CA zone 9b
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In the textbook Alternative Construction Contemporary Natural Building Methods, there is a small diagram of a light straw wall with wood studs on only one side of the wall. The diagram is by Lou Host-Jablonski. I'm trying to figure out how to secure the form board on the frame-less side. Is this by using steel cross ties through holes drilled in the plywood similar to concrete formwork? Or can the frameless side be formed by attaching a floor to ceiling formboard to the plates, backed by 2x on edge? This would require complete sections be filled at a time. Wouldn't the steel cross ties create thermal bridges?
While I love timber frame, and not opposed to a larsen truss type wall, which seems to use more wood... I think the following would be the most cost effective solution. 16oc 2x6 structural walls with 12in thick natural R-21 walls.
Now the tricky part...I'm in redwood country, we're burning redwood chips for our local utility grid. We have to truck straw in from the central valley. Can a one sided framed wall structure support a wall of chip-slip? I think redwood chips encased in clay might last for a hundred years or so...maybe even the bark? does chip slip require all the lathe? if so then you need something to attach the lathe to.
we're trying to do this with bank financing so i don't want any hassle as far as getting plans approved and finding a contractor who can do the work (or sneak me in under the radar and let me do the work)
any help appreciated
 
Bill Bradbury
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Hi Tim,

Larsen truss is the way to go. No you don't need lath for any solid mass wall assembly, just plaster right on the clay/chip.

All Blessings,
Bill
 
Jay C. White Cloud
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Hi Tim,

I concur with Bill B. WTS is the way to go...

I have reached out to Lou, who is a colleague within my "natural building circles," to see if he has anything to add. "Wall Truss Systems" - WTS (a.k.a. Larsen Truss) we have used for over 35 years in various ways. It is now the only real way I would close in a timber frame, or some related "thick wall" modality. I don't build with less than "actual" timber stock as I don't buy "box store" wood. So my stud and other timber products come straight off a mill someplace. I also seldom employ/recommend anything smaller than a 50mmx150mm (~2"x6") and normally prefer a 60mmx200mm (~2"x8") studs for WTS. Your project appears to be in a tectonic region of some note, and there requires even more substantial framing, so wouldn't recommend anything lighter than a 2x8 frame system with good flexible horizontal bracing methods and also a timber frame superstructure. WTS alone could achieve the load requirements, but that will take almost as much (or more??) work than a timber frame. Then the WTS can go as far as 600 to 1 meter on center, depending on the other design parameters.

As for "using more wood" that isn't true at all, if al the other consideration are taken into account. I make the WTS from 60mmx200mm (~2"x8") split into an outer rib of 50x75mm and inner rib of 50x125mm with spans every 500mm. So whether a stud is used as just a 2x or split add very little more significant wood, and when other considerations are taken in, it is much better in design and structure.

I do need to ask, are you doing the build? Have you build in a tectonic zone before? Do you have a PE? Is the design finalized and may we see pictures.

Regards,

j

 
Tim Nam
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Location: Arcata, CA zone 9b
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Thank you for the feedback. I just wonder what the intention was of including that diagram in the book if not to save on labor and wood, while maintaining a thick insulative natural wall.

Um, no the bank nor the city will allow me to do the build though that would be my preference. I have not built in a seismic zone. I'm not a PE though I have a degree in ME. The design is far from being finalized. I do have some sketchup models I've been playing with and I'd be happy to share if you're really interested. In one I had a timber frame of 8x8 and then I added a WTS with 24in spacing and it just looked like so much excessive lumber. So then I thought well if all this 2x is necessary can we ditch the timberframe? So I modeled a version with only WTS of 2x4 (on both sides) 24in oc and it still looked like a tremendous amount of lumber. So I've been stalling and ruminating and came across that diagram and thought, eureka! but I couldn't figure out the forming so I posted up here.

Regarding extra engineering for seismic concerns. The city's policy is the building should meet 2010 IBC. So I don't think there are extra measures that need to be taken for seismic issues, legally speaking, though robust design and deep pockets might want to play it safer. I don't want my house to collapse on me, but I also have this tight budget and a feeling like this apartment is a cage that is slowly killing me and having to finance land, design, plan, permit and build more or less all at once. So as in most cases its a delicate balance of wanting something badly but trying to not stress out about it too much.

I just get so frustrated with the invisible structures, especially in light of folks that are homeless. I mean, for example, the regulations won't allow composting toilets or graywater, or even a mobile home on a lot due to sewage concerns, in effect making it harder for people to secure housing. In the meantime, the homeless camp illegally in the brush and poop and pee where they must. So are these regulations really helping? If we didn't have these regulations would people really shit in their own front yard? give me a break.

I have to vent a little every once in awhile or I might explode. Thanks again.
Tim

 
Jay C. White Cloud
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I just wonder what the intention was of including that diagram in the book if not to save on labor and wood, while maintaining a thick insulative natural wall.


If I can get a copy, I would understand better the goal. These systems are not meant to "save wood" but to build a structure with "good practice," and multigenerational durability...thereby reflecting sustainability.

Um, no the bank nor the city will allow me to do the build though that would be my preference..I have not built in a seismic zone. I'm not a PE though I have a degree in ME. The design is far from being finalized.


I am not really clear on this...there are many owner builders throughout California?? I do understand that some banks can be a challenge, yet a descent GC that works in these modalities should have no issue with you working with them if you can be safe and follow directions...

I do have some sketchup models I've been playing with and I'd be happy to share if you're really interested.


Please DO!! We love pictures and playing with models!!

In one I had a timber frame of 8x8 and then I added a WTS with 24in spacing and it just looked like so much excessive lumber. So then I thought well if all this 2x is necessary can we ditch the timber frame?


Simply put...timber frames are always going to be superior than other modalities by themselves. Again, it isn't about "saving wood," its about building well...

So I modeled a version with only WTS of 2x4 (on both sides) 24in oc and it still looked like a tremendous amount of lumber. So I've been stalling and ruminating and came across that diagram and thought, eureka! but I couldn't figure out the forming so I posted up here.


Hmmm....take two 2x4 and attach a span and you have a wall truss. Pretty simple and way more "pros" than "cons" for why to use them...compared to other systems....

Regarding extra engineering for seismic concerns. The city's policy is the building should meet 2010 IBC.


I don't build to CODEs (these are minimums) and "minimums" are not a reflection of "best practice." These "minimums" are why more than half our public infrastructure in this country needs to be replace after only 30 to 50 years of service...


...I don't think there are extra measures that need to be taken for seismic issues, legally speaking, though robust design and deep pockets might want to play it safer. I don't want my house to collapse on me, but I also have this tight budget and a feeling like this apartment is a cage that is slowly killing me and having to finance land, design, plan, permit and build more or less all at once. So as in most cases its a delicate balance of wanting something badly but trying to not stress out about it too much.


Natural building can very much be "frugel building" and there are many stories here at Permies.com (et al forums) about folks that achieve it. I am not speaking of "extra measures." I am speaking of the "correct measures."

Folks here love to help, so if there are specific questions, please do ask!...
 
Tim Nam
Posts: 74
Location: Arcata, CA zone 9b
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Cool, I'll start with some screenshots just because they're probably easier viewing. If you (anyone) wants the sketchup file I can email it to you. Remember I know very little about timberframing so these models were mostly an exercise in drawing and visualising how joints might fit and be strong.
WTS model.JPG
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WTS model
timberframewithWTS.JPG
[Thumbnail for timberframewithWTS.JPG]
timberframewithWTS
concept.JPG
[Thumbnail for concept.JPG]
concept with shell
 
Tim Nam
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Location: Arcata, CA zone 9b
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My specific question is whats up with that diagram in the textbook showing a light straw wall with 2x6 framing on only one side of the wall? how do you form for that?
 
Tim Nam
Posts: 74
Location: Arcata, CA zone 9b
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I understand you're interested in building well, but if the owner can't afford it then what? Why is it so hard to acknowledge that people have constraints in their budgets and lives?
 
Tim Nam
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Location: Arcata, CA zone 9b
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Humboldt and Mendocino Co have owner builder exemptions that I know of but I'm pretty sure the City of Arcata doesn't and the bank definitely does not allow owner builder. Since we don't own the land yet, we have to jump through the bank's hoops. And we can't even consider outside the city because my wife doesn't drive (I've seen how cheap land is near Weitchpec, and Shasta and Modoc, and SC Oregon, believe me) so we're in a tough spot but I'm just chipping away to get a set of plans for a house we can afford that I think we can get a GC to build or put me on the payroll or whatever to let me do some work without letting the bank know, get a loan approved and plans approved and all the rigamarole. (I'm hoping to avoid an architect and just have drawings drawn and plans engineered and stamped) Its daunting and I don't know if I'm up for it but I'm just putting one foot down at a time because that's all I can do. Before, I was pretty against the idea of borrowing from a bank but after a pretty thorough search of any possible alternatives I came to the realization that borrowing is currently the only way to move forward for folks in our situation. Or just defer the dream? Theres always that. Well, in the light of possible collapse of civilization, whatever that may mean, I still think I'd prefer to be on a (small) piece of land with roots in the ground even if the bank or Sheriff's came to take it away, one might have a slightly better chance if they're already on the land putting roots in the ground, stacking carbon, spreading and soaking water... Again, I do appreciate the feedback and this forum even though I keep slipping towards whining and griping.
 
Jay C. White Cloud
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It's late, and I am sure others will add their views, but for an area that gets over 42" of average rainfall a year (that's about what we get in my area) a flat roof is just a big...$$expensive$$...problem waiting to happen. That is a guaranteed when, not if... I won't design, build or facilitate any flat roofs...nor can I get contractors insurance on them...If I am part of one, it is a "faux" effect, in the sense that there is a 4/10 to 9/12 pitch and a flat framed deck over that. This can work in some designs, yet typically isn't worth the effort. I would also suggest at this point, if being frugal about wood was a concern, among other issues of frugality...a flat roof is the last thing to have...

My specific question is whats up with that diagram in the textbook showing a light straw wall with 2x6 framing on only one side of the wall? how do you form for that?


I tried to find it, and if Lou gets in touch I will ask, yet I suspect it is a misinterpretation of a "cross sectional view," and the outer framing armature has been omitted for visual clarity...not a lack of structure. The other possibility is that the outer wall is a more solid cobb matrix and the inner is the "slip clay" matrix.

I understand you're interested in building well, but if the owner can't afford it then what? Why is it so hard to acknowledge that people have constraints in their budgets and lives?


It isn't hard to acknowledge fiscal constraints at all, and many in the traditional/natural building movement come to it because they don't have money...yet...those constraints don't change that either one has to spend "money" or spend "time"...it's one or the other and typically a mix of the two...pursuant to the size and type of architecture. So spend a lot of time learning, gathering materials, and planning and little money, or spend money and hire someone to do it quicker...That is kind of the way it is with most things...

I bought my first "old house" that was a real "fixer upper" when I was 17 years old ( 1978 )...it took me two years to scrounge and/or make the materials I needed for my next project which was my first "self built" timber frame house at 24'x24' with a loft. Neither the "old house" ($30,000 today's equivalence) nor the timber frame ($6000 in today's equivalence) cost much monetarily...they both took effort and time...

I have seen others do more with less since my first adventures in architecture...It seems where there is a will there is a way...

Tim...what is your target price for achieving a turn key project per square foot...??
 
Tim Nam
Posts: 74
Location: Arcata, CA zone 9b
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Good morning,
Had a rough night tolerating noisy bass fanatic neighbors. As 2AM drew near I broke down and went over and asked them to kill the noise but my emotions slipped and I banged on their door with extra heavy emphasis...sigh...so they turned off the "music" but I was up til 4 hearing them talking and laughing loudly...wonder what the topic was...

So Jay, I hear what you're saying about the flat roof. As I said our designs are far from final and the flat roof is something I find ideal but certainly not required. I mean in terms of literally stacking functions it makes sense to use roof space as living space, though structurally I can see how it might be a challenge. I'm sure its due to the materials used, but I find it interesting given what you said, Jay about flat roofs, that nearly every commercial building I see has a flat roof. I also see houses with flat roofs all around but maybe they're just failures waiting to happen, or their owners were able to invest in some effective but probably unsustainable material.

Oh yeah, I took a picture of the diagram. It doesn't seem to be related to the surrounding text perse, but I'll take one more look to try to find more context.

Our target price per sq ft is around $150, this is just pushing our limits. The land will probably be around 220k ish (for 3+ acres) hopefully we can get them down to 200k which then would leave us with about 150k to do the rest from bare land. The house design is staying around 750-800 sq ft.
20150510_101339.jpg
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Tim Nam
Posts: 74
Location: Arcata, CA zone 9b
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lets see what happens if i attach a sketchup model
Filename: house model.skp
Description:
File size: 375 Kbytes
[Download house model.skp] Download Attachment
 
Tim Nam
Posts: 74
Location: Arcata, CA zone 9b
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here's the WTS one
Filename: wall truss section.skp
Description:
File size: 389 Kbytes
[Download wall truss section.skp] Download Attachment
 
Jay C. White Cloud
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Hey Tim,

First, I think those Sketchup models are really good. Just drawing these can different systems can teach a great deal...

I mean in terms of literally stacking functions it makes sense to use roof space as living space, though structurally I can see how it might be a challenge.


It can be a great place to extend seasonal living space, like a green house for example. The method of facilitation is where it gets tricky...

I'm sure its due to the materials used, but I find it interesting given what you said, Jay about flat roofs, that nearly every commercial building I see has a flat roof. I also see houses with flat roofs all around but maybe they're just failures waiting to happen, or their owners were able to invest in some effective but probably unsustainable material.


This is very true...many flat roofs, and almost every single one of them leaks in some small (or great) degree. Building practices today only create work in the future for the builder. This almost seems designed into most systems. Even the flat roofs I have seen that are done well...will often get undone because some contractor sees fit to change it to "what they know" instead of a more durable system.

Flat roofs can be done...they are never less expensive or enduring compared to pitched, unless we are speaking of arid regions...

Our target price per sq ft is around $150, this is just pushing our limits. The land will probably be around 220k ish (for 3+ acres) hopefully we can get them down to 200k which then would leave us with about 150k to do the rest from bare land. The house design is staying around 750-800 sq ft.


Appears achievable... I look forward to following along...

Regards,

j
 
Jay C. White Cloud
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Hi Tim,

Lou (Lou Host-Jablonski) reached out to me, yet is very busy...He may or may not join the conversation. Let me know if you have other questions, and Lou is on "LinkedIn" and has a practice in Madison, WI should you care to ask him directly your questions. Do please keep this post going with your progress and findings...

Regards,

j
 
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