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Sep 01
Love0

Red oak borer larvae found in roundwood

By Reciprocal Roof

Today, I found some red oak borer larvae living in some of my pin oak rafter poles. At least one of my roundwood rafters has been lying in the grass (on some pretty measly sticks of wood to keep it off the ground) with all of its bark intact since perhaps April.

Needless to say, I wasn’t happy to encounter them tunneling through the wood. I’m not sure how serious this issue is (thankfully, the wood wasn’t completely riddled). I cursed their existence generally. But I think the pole is still good to go for the reciprocal roof construction.

This whole roof business has been a bit like walking blindly down an alley for me, since I have never worked with pole wood or built a roof (or even helped to build one). I have been quite uncertain about the whole process thus far: whether or not my poles are strong enough, whether or not they are long enough, whether or not they are seasoned enough (this I know is not the case: most of my poles were only cut in March, but I’m going for it anyway), etc.

Well, I guess I’ll know at least some of these answers on Wednesday when I have a roof raising party and get the reciprocal roof assembly built!

Aug 31
Love0

The cob walls are complete

By Cob Building

194.5 batches of cob stomped by foot and applied by hand and you get:

100percentcobwalls

Yesterday afternoon and this morning, I put some final touches on the cob walls, leveling them in preparation for the soon-coming reciprocal roof. After I smoothed out some of the last cobs, I took a minute as I stood on the lean-to trestle, just staring down at the walls which now easily tower over my head, and I wondered in amazement.

It has been quite a journey to this point, moving over 40 tons of material. That’s a lot of earth. More specifically, it’s been 194.5 batches of cob so far. All this over 57 days (which were not all full work days, mind you.)

And it’s not over yet, but this massive portion of the process is, at least. Here are some photos of the structure.

100percent-int-s
Interior, looking southwest.The bed will be positioned along the far wall, under the window. The joists will support a 7.5′ wide, 22″ deep storage shelf.

100percent-int-n 100percentcobwalls-n
The north wall interior, with nooks and a shelf at the foot of the (future) bed. The rocket stove will be to the left of the window. Exterior backside, looking southwest.

100percent-doorway 100percent-biigshelf
Entryway with storage nooks. A gigantic corner bookshelf.

100percent-whew
Happy.

Aug 29
Love0

Cob walls are 99%

By Cob Building

Here’s a couple of photos of the 99% complete cob walls. I figure I’ll be able to finish them off tomorrow, perhaps Sunday if it takes a couple more batches than I expect. Reciprocal roof: here we come!

Also, in the top photo you might notice a post near the entryway. This black locust post will bear one of the reciprocal roof rafters, making for a nice little overhang near the entryway. Call it a really small porch, maybe, but this should provide some decent extra coverage from the elements.

Aug 26
Love0

The end is (seriously) near

By Cob Building

biggwallll

With the help of my superstar work exchangers Dan and Danielle, the cob walls are nearly complete. Unfortunately, D&D departed today to begin their own pursuits, but I am hopeful that I’ll be able to complete cobbing by myself by the weekend. I suspect it will take 10 or so batches to level out the walls in preparation for the reciprocal roof – no problem! (My estimations are historically inaccurate, but I feel pretty confident about this one.)

It’s amazing how tall the west wall (see above) is/feels, compared to the rest of the house. A little bit of slope can go a long way.

Last night we had a third campfire in the house, and several folks have suggested leaving the house as is, without roof, because of the dramatic light cast by the fire on the walls. It’s quite a sight. Maybe I’ll have to design a retractable roof…

Aug 19
Love0

The story so far

By Cob Building

cobhouse-nw01

Recent highlights the past week included cobbing above the south window, removing the door brace (ahhh for easy entering and exiting!), and sticking in most of the deadmen for the roof rafters. It feels more and more like an actual house with each passing day.

lookingeast lookingsouth

Aug 18
Love0

Moonlight cobbing

By Cob Building

cobcampfire

This weekend, I had a strong urge to do some cobbing after dinner, during the sunset hours. So, last night we (myself and Dan and Danielle [my two work exchangers], later joined by Liat) ate dinner and stomped a batch of cob as the sun went down. By the time we were done stomping, it was super dark and pretty dang difficult to actually get the cob on the walls, but we managed.

After that first batch of cob, we figured it would be a good idea to make a campfire inside of the house. Ted and I set one up, and the house glowed like a giant woodstove. It looked great from the road, with a bright orange aura.

There was a full moon that cast a great light on the walls as it rose towards the sky later that night.

Fun stuff.

Aug 15
Love0

Installing shelf joists in cob and inching closer to the roof

By Cob Building, Cob Shelves

in-window
(Satisfied after today’s good progress – See the new cob at the top of the wall there?)

With help from my most enjoyable new work exchangers Dan and Danielle, I am inching closer and closer to the roof of my cob house. Today marked the completion of one of the few remaining and more challenging elements before that happens, though — installing joists for a wide shelf positioned above the (future) cob bed.

shelf-joist

Yesterday, we built a joist rig with some 2×4s that could be buried in the cob: three 38? long joists attached to one long 2×4 banged out with lots of nails. This whole thing was placed on the cob wall and leveled, joists braced, and then cobbed in place. Hopefully the joists will be strong, as they are buired in all 16? of the cob wall. The shelf will be 22? wide and 7.5? long and will mostly be for storage.

leveling-joists joists-buried

Time will tell whether or not the joists are buried in enough wall to support the weight of potential clutter on the shelf. I am hopeful!

Aug 12
Love0

Reciprocal roof video: removing the charlie stick

By Video, Reciprocal Roof

By sheer chance, I found this YouTube video in which several builders remove the ‘charlie stick’, or temporary support for a reciprocal roof frame. It looks like it is perhaps Tony Wrench’s account, but unfortunately he has no other videos about the building process. But this is indeed helpful! It gives me clues about the construction process:

– The charlie stick does not seem to be buried at all, which makes me think that they simply braced it (making it easier to remove later)

– The whole structure does settle once the post is removed, but not much, so the pitch is indeed “what you get”

– The top of the rafters look to be left untrimmed to their final size, which I assume gives the builder some wiggle room

Aug 11
Love0

Preparing for building the reciprocal roof frame

By Living Sod Roof, Reciprocal Roof

The past few days, I have been dwelling quite heavily on the roof design for my cob house. I will be constructing what is called a reciprocal roof, a self-supporting structure composed of pin oak and black locust poles. Reciprocal roofs are round and spiral-y, perfect for round structures. They require no center post and are apparently “simple” to construct, requiring no experience. Plus, they look great, too.

The only downside to building a reciprocal roof is the apparent lack of really comprehensive information out there on how to actually do it. Running a Google search for reciprocal roofs results in a few decent hits, but still, there seems to be a dearth of hard information on how to go about making a reciprocal roof from start to finish.

The best resource I have found thus far is Tony Wrench’s book, How To Build a Low-Impact Roundhouse. You can see some photos of his design here. Wrench has some good sketches and a decent amount of how-to information in his book (which, by the way, is pretty hard to find), but I’m still craving more. Perhaps because my case is pretty different from his and I want to be reassured that this thing is going to work.

The main difference being that my walls are load-bearing, with the reciprocal roof rafters resting directly on the cob walls. Oh, and my house is also not totally circular… That makes a big difference, too.

But anyway, here are a few other sources of images and information for the prospective reciprocal roofer:

  • The LessPress Snail Cabin has a reciprocal roof made with dimensional lumber. Also, be sure to check out their Excel spreadsheet for calculating beam lengths and positions for both circular buildings and otherwise
  • Zone5 has a brief description with some images of a Tony Wrench-style reciprocal roof construction for a roundhouse here and here
  • Check out a scale reciprocal roof model and design using dimensional lumber at Casa de Baro
  • Cae Mabon in Snowdonia of North Wales features several buildings with reciprocal roofs. Images here
  • Simon Dale’s ‘low impact woodland home‘ has a gorgeous reciprocal roof with gnarly rafters and beautiful slab decking
  • For math nerds, visit The Pavilion for a very technical description of how reciprocal roofs function
  • Design Forward has a very brief snippet about the history of the reciprocal roof design, which was invented by Graham Brown, who says: “The structure demonstrates a principle that is fundamental to life on this planet – a simple natural principle: All life is connected.” (Unfortunately, Brown’s website is down…)

This is mostly what I have been reading and looking at for inspiration. I guess the only way to determine if my own reciprocal roof design works is actually making this thing. Soon enough, I will know!

(Image from Zone5.org)