Wednesday, March 2, 2011

Here's something I'll bet you've never done!

D: Have you ever used a weed-whacker?

Me: Not on a wall.

D's still getting over his knee surgery, and D&L are way behind schedule. They're building a very elaborate 4000 sq ft house, whose outside walls are constructed entirely of straw bales. It turns out one of the necessary steps, prior to mudding the walls, is to smooth out the surface of the bales. Makes sense, I suppose. The tool of choice? A weed-whacker!

It takes a long time. A very, very long time. My back hurts. I'm nowhere near halfway done. Money! Ha ha!

Seriously, I've got a gig booked every day this week except Monday, and I wish I'd started this particular one on Monday. It's been a lean few weeks, but they're over for a while.


Anonymous said...

I know of a couple of women in the area who built a straw bale house several years ago. I've been trying to get a tour of it but haven't connected yet. Sounds like an interesting concept but I wonder about long term durability. I built an unconventional super insulated home 25 years ago and I have no regrets. I did hold my breath alot for the first few years but it turns out nothing unexpected happened.

Plug Nickel Outfit said...

Joel - are the bales bearing - or is there a frame to support the trusses and roof? That used to be the big issue for folks wanting to do straw bale in places where local approval was necessary.

Straw bale construction is pretty interesting - provides a lot of thermal mass. I can't speak for other places - but in the US SW - if one can play the daily thermal cycle right - very little extra energy has to go into heating and cooling.

Anon 7:32p - I think that if one can keep moisture at bay - the straw bale should be pretty durable. There's a lot of factors to durability. If one tries to build monolithic structures of straw bale with no bearing support - 50 years or so could about it. Straw bale might last a lot longer if viewed as a more flexible structure without too much bearing weight. Someone could build a frame of girders and infill with straw bale and have a very long lived house.

Anonymous said...

I would think the line would pull some of that straw out, but I've never done it before. Yeah, waving a 5 pound wand back and forth from knee height to over your head don't sound like much fun to me either.

Would maybe hedge shears work better? Before they made line trimmers, I used to use them to cut the buffle grass around our ranch cabin. Would go down to around ankle height and cut - went pretty quickly, but then again, I was a young 20 something, not this old 48 year old bag of scars, lol.

Ibuprofen, 4 - 200 milligrams should help do the trick.

MamaLiberty said...

I've always sort of leaned toward the idea of rammed earth walls. Never saw a straw bale house, so the photo is most illuminating. I like the nice windows. Didn't know you had to shave the bales after they were in place. That does sound like a monster of a job.

Some people here take an old trailer and construct tight walls of straw bales around it, then roof over the whole thing.

Sounds pretty ugly to me, but I've not seen one. I'd think that would really cut down on the light coming in from outside, which would be the worst part for me. I'm an open window, lots of sunshine kind of gal. And we have months where there isn't much of it even with lots of big windows.

Claire said...

Plug Nickel Outfit -- Since Joel may be too busy weed-whacking to answer, I'll speak up. I know this particular house, and no, the straw bales are not load-bearing. They're placed within a wondrously strong post-and-beam framwork (with joints hand-hewed by the incredibly meticulous D.). The house is really, really, really a beauty. And well-engineered. But it's definitely common in the neighborhood to question D & L's sanity for tackling this project! It not only has straw-bale exterior walls, but earth-bag interior walls, which are unbelievably labor-intensive. Gonna be a beauty, though, when they're done. -- Claire

Joel said...

PNO, for a look at the house's load bearing structure, click here.

The Grey Lady said...

A weed whacker?????

Wouldn't a hedge trimmer be faster and give a better edge? Coming from a lady that knows exactly NOTHING about the process.

Plug Nickel Outfit said...

Thanks, Claire! Thanks for the link, Joel. In the photo for this post there's a tall stem wall (which is a good thing for straw bale - prevents wicking) but I don't see the stem wall in the earlier pics - was that built-up at a later time? That's a lot of wood in those earlier pics - must have driven someone crazy working out the details of the tenon locations. I've worked on a couple projects where people made steel plates and then dressed them to look like old wrought iron to avoid using the hurricane straps - but that can get expensive... Those interior walls can get real heavy - the pier footings may not have been a bad idea.

How are they approaching the plastering? Are they going for breathablility or totally impermeable? This was an issue for a while with adobe structures - sometimes in restoration people would use a waterproof plaster - but more recently it was figured out that adobe needs to 'breathe' and restorers shifted back to permeable materials. I'm just wondering how they're approaching that with the straw as a factor...

I wonder if they pre-treated the soil for termites? After moisture being a problem - they'd be the next thing I'd be concerned about - particularly without an integrated foundation. Maybe that's why ox blood was traditionally used in adobe floors - could turn out it not only gives a particular color to the floor - but repels termites!

Joel said...

There's a concrete wall foundation (you can see it in my lousy photo) that supports the straw bales and prevents wicking. No wood touches the ground, and I don't expect termites to be a big problem. The floors will be adobe - L has a great recipe for adobe, but I don't think it concludes ox blood.

As to the plastering, I think they're still noodling that. Last summer they mudded the windward bales, using native clay, but really screwed up - it all washed off halfway through Monsoon, and they ended up having to replace a bunch of moldy bales. It's a work in progress.

Plug Nickel Outfit said...

Hey Joel - I hope I'm not bending your ear too much over this. I used to informally study traditional building techniques - so I have an interest in this stuff.

Using plain adobe for plastering won't last very long - I've tried it myself. Lime and/or gypsum were traditional materials used in plastering. They'd give a resistant surface but allow for breathing.

Here's a couple links that came up early with a basic search:

The Use of Gypsum Plaster

Traditional Lime Plaster

With traditional plastering over adobe it's still necessary to go back every 2-3 years and re-plaster.

I think somewhere earlier on your blog you may have mentioned you're somewhat near Zuni Pueblo. Tracking down some old-timer there might be a good way to get some tips on plastering that works - modern day tradesmen just don't learn this stuff. Some of the best info I ever picked up about plastering was during a 45 minute talk with some guy who I bumped into at Taos Pueblo who was plastering a wall.

Btw - I've seen termites come up through cracks in 3-4" concrete foundations - through carpet and through the 3/4" side of a plastic dairy crate just to munch away at the jackets of record albums. They ate most of the jacket from Alice Cooper's 'Billion Dollar Babies' and a Joe Cocker album and it didn't seem to give them indigestion! I wouldn't underestimate termites - they're good at what they do.